app: fix automatic window decoration action processing

This commit adapts the use of the automatic window decorations to the
event processing changes introduced in v0.4.0. You must update widget
state before laying it out, not after. Doing so after (as this code used
to do) results in discarding updates.

Fixes: https://todo.sr.ht/~eliasnaur/gio/542
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>

app/app.go

@@ -3,16 +3,9 @@
 package app
 
 import (
-	"image"
 	"os"
 	"path/filepath"
 	"strings"
-	"time"
-
-	"gioui.org/io/input"
-	"gioui.org/layout"
-	"gioui.org/op"
-	"gioui.org/unit"
 )
 
 // extraArgs contains extra arguments to append to
@@ -27,77 +20,23 @@ var extraArgs string
 // On Android ID is the package property of AndroidManifest.xml,
 // on iOS ID is the CFBundleIdentifier of the app Info.plist,
 // on Wayland it is the toplevel app_id,
-// on X11 it is the X11 XClassHint.
+// on X11 it is the X11 XClassHint
 //
-// ID is set by the [gioui.org/cmd/gogio] tool or manually with the -X linker flag. For example,
+// ID is set by the gogio tool or manually with the -X linker flag. For example,
 //
 //	go build -ldflags="-X 'gioui.org/app.ID=org.gioui.example.Kitchen'" .
 //
 // Note that ID is treated as a constant, and that changing it at runtime
-// is not supported. The default value of ID is filepath.Base(os.Args[0]).
+// is not supported. Default value of ID is filepath.Base(os.Args[0]).
 var ID = ""
 
-// A FrameEvent requests a new frame in the form of a list of
+func init() {
-// operations that describes the window content.
+	if extraArgs != "" {
-type FrameEvent struct {
+		args := strings.Split(extraArgs, "|")
-	// Now is the current animation. Use Now instead of time.Now to
+		os.Args = append(os.Args, args...)
-	// synchronize animation and to avoid the time.Now call overhead.
-	Now time.Time
-	// Metric converts device independent dp and sp to device pixels.
-	Metric unit.Metric
-	// Size is the dimensions of the window.
-	Size image.Point
-	// Insets represent the space occupied by system decorations and controls.
-	Insets Insets
-	// Frame completes the FrameEvent by drawing the graphical operations
-	// from ops into the window.
-	Frame func(frame *op.Ops)
-	// Source is the interface between the window and widgets.
-	Source input.Source
-}
-
-// Insets is the space taken up by
-// system decoration such as translucent
-// system bars and software keyboards.
-type Insets struct {
-	// Values are in pixels.
-	Top, Bottom, Left, Right unit.Dp
-}
-
-// NewContext is shorthand for
-//
-//	layout.Context{
-//	  Ops: ops,
-//	  Now: e.Now,
-//	  Source: e.Source,
-//	  Metric: e.Metric,
-//	  Constraints: layout.Exact(e.Size),
-//	}
-//
-// NewContext calls ops.Reset and adjusts ops for e.Insets.
-func NewContext(ops *op.Ops, e FrameEvent) layout.Context {
-	ops.Reset()
-
-	size := e.Size
-
-	if e.Insets != (Insets{}) {
-		left := e.Metric.Dp(e.Insets.Left)
-		top := e.Metric.Dp(e.Insets.Top)
-		op.Offset(image.Point{
-			X: left,
-			Y: top,
-		}).Add(ops)
-
-		size.X -= left + e.Metric.Dp(e.Insets.Right)
-		size.Y -= top + e.Metric.Dp(e.Insets.Bottom)
 	}
-
+	if ID == "" {
-	return layout.Context{
+		ID = filepath.Base(os.Args[0])
-		Ops:         ops,
-		Now:         e.Now,
-		Source:      e.Source,
-		Metric:      e.Metric,
-		Constraints: layout.Exact(size),
 	}
 }
 
@@ -124,15 +63,3 @@ func DataDir() (string, error) {
 func Main() {
 	osMain()
 }
-
-func (FrameEvent) ImplementsEvent() {}
-
-func init() {
-	if extraArgs != "" {
-		args := strings.Split(extraArgs, "|")
-		os.Args = append(os.Args, args...)
-	}
-	if ID == "" {
-		ID = filepath.Base(os.Args[0])
-	}
-}

app/doc.go

@@ -8,19 +8,21 @@ See https://gioui.org for instructions to set up and run Gio programs.
 
 # Windows
 
-Create a new [Window] by calling [NewWindow]. On mobile platforms or when Gio
+Create a new Window by calling NewWindow. On mobile platforms or when Gio
 is embedded in another project, NewWindow merely connects with a previously
 created window.
 
-A Window is run by calling its NextEvent method in a loop. The most important event is
+A Window is run by calling NextEvent in a loop. The most important event is
-[FrameEvent] that prompts an update of the window contents.
+FrameEvent that prompts an update of the window contents.
 
 For example:
 
+	import "gioui.org/unit"
+
 	w := app.NewWindow()
 	for {
 		e := w.NextEvent()
-		if e, ok := e.(app.FrameEvent); ok {
+		if e, ok := e.(system.FrameEvent); ok {
 			ops.Reset()
 			// Add operations to ops.
 			...
@@ -30,7 +32,7 @@ For example:
 	}
 
 A program must keep receiving events from the event channel until
-[DestroyEvent] is received.
+DestroyEvent is received.
 
 # Main
 
@@ -55,6 +57,12 @@ For example, to display a blank but otherwise functional window:
 		app.Main()
 	}
 
+# Event queue
+
+A FrameEvent's Queue method returns an event.Queue implementation that distributes
+incoming events to the event handlers declared in the last frame.
+See the gioui.org/io/event package for more information about event handlers.
+
 # Permissions
 
 The packages under gioui.org/app/permission should be imported

app/ime_test.go

@@ -11,8 +11,8 @@ import (
 
 	"gioui.org/font"
 	"gioui.org/font/gofont"
-	"gioui.org/io/input"
 	"gioui.org/io/key"
+	"gioui.org/io/router"
 	"gioui.org/layout"
 	"gioui.org/op"
 	"gioui.org/text"
@@ -31,10 +31,10 @@ func FuzzIME(f *testing.F) {
 	f.Fuzz(func(t *testing.T, cmds []byte) {
 		cache := text.NewShaper(text.WithCollection(gofont.Collection()))
 		e := new(widget.Editor)
+		e.Focus()
 
-		var r input.Router
+		var r router.Router
-		gtx := layout.Context{Ops: new(op.Ops), Source: r.Source()}
+		gtx := layout.Context{Ops: new(op.Ops), Queue: &r}
-		gtx.Execute(key.FocusCmd{Tag: e})
 		// Layout once to register focus.
 		e.Layout(gtx, cache, font.Font{}, unit.Sp(10), op.CallOp{}, op.CallOp{})
 		r.Frame(gtx.Ops)

app/internal/xkb/xkb_unix.go

@@ -238,17 +238,17 @@ func (x *Context) UpdateMask(depressed, latched, locked, depressedGroup, latched
 		C.xkb_layout_index_t(depressedGroup), C.xkb_layout_index_t(latchedGroup), C.xkb_layout_index_t(lockedGroup))
 }
 
-func convertKeysym(s C.xkb_keysym_t) (key.Name, bool) {
+func convertKeysym(s C.xkb_keysym_t) (string, bool) {
 	if 'a' <= s && s <= 'z' {
-		return key.Name(rune(s - 'a' + 'A')), true
+		return string(rune(s - 'a' + 'A')), true
 	}
 	if C.XKB_KEY_KP_0 <= s && s <= C.XKB_KEY_KP_9 {
-		return key.Name(rune(s - C.XKB_KEY_KP_0 + '0')), true
+		return string(rune(s - C.XKB_KEY_KP_0 + '0')), true
 	}
 	if ' ' < s && s <= '~' {
-		return key.Name(rune(s)), true
+		return string(rune(s)), true
 	}
-	var n key.Name
+	var n string
 	switch s {
 	case C.XKB_KEY_Escape:
 		n = key.NameEscape

app/os.go

@@ -132,7 +132,7 @@ func (o Orientation) String() string {
 }
 
 type frameEvent struct {
-	FrameEvent
+	system.FrameEvent
 
 	Sync bool
 }
@@ -160,7 +160,7 @@ type driver interface {
 	// ReadClipboard requests the clipboard content.
 	ReadClipboard()
 	// WriteClipboard requests a clipboard write.
-	WriteClipboard(mime string, s []byte)
+	WriteClipboard(s string)
 	// Configure the window.
 	Configure([]Option)
 	// SetCursor updates the current cursor to name.

app/os_android.go

@@ -123,14 +123,12 @@ import (
 	"fmt"
 	"image"
 	"image/color"
-	"io"
 	"math"
 	"os"
 	"path/filepath"
 	"runtime"
 	"runtime/cgo"
 	"runtime/debug"
-	"strings"
 	"sync"
 	"time"
 	"unicode/utf16"
@@ -139,12 +137,12 @@ import (
 	"gioui.org/internal/f32color"
 
 	"gioui.org/f32"
-	"gioui.org/io/input"
+	"gioui.org/io/clipboard"
 	"gioui.org/io/key"
 	"gioui.org/io/pointer"
+	"gioui.org/io/router"
 	"gioui.org/io/semantic"
 	"gioui.org/io/system"
-	"gioui.org/io/transfer"
 	"gioui.org/unit"
 )
 
@@ -158,7 +156,7 @@ type window struct {
 	fontScale float32
 	insets    pixelInsets
 
-	stage     Stage
+	stage     system.Stage
 	started   bool
 	animating bool
 
@@ -166,10 +164,10 @@ type window struct {
 	config Config
 
 	semantic struct {
-		hoverID input.SemanticID
+		hoverID router.SemanticID
-		rootID  input.SemanticID
+		rootID  router.SemanticID
-		focusID input.SemanticID
+		focusID router.SemanticID
-		diffs   []input.SemanticID
+		diffs   []router.SemanticID
 	}
 }
 
@@ -503,7 +501,7 @@ func Java_org_gioui_GioView_onCreateView(env *C.JNIEnv, class C.jclass, view C.j
 	w.loadConfig(env, class)
 	w.Configure(wopts.options)
 	w.SetInputHint(key.HintAny)
-	w.setStage(StagePaused)
+	w.setStage(system.StagePaused)
 	w.callbacks.Event(ViewEvent{View: uintptr(view)})
 	return C.jlong(w.handle)
 }
@@ -518,7 +516,7 @@ func Java_org_gioui_GioView_onDestroyView(env *C.JNIEnv, class C.jclass, handle
 func Java_org_gioui_GioView_onStopView(env *C.JNIEnv, class C.jclass, handle C.jlong) {
 	w := cgo.Handle(handle).Value().(*window)
 	w.started = false
-	w.setStage(StagePaused)
+	w.setStage(system.StagePaused)
 }
 
 //export Java_org_gioui_GioView_onStartView
@@ -534,7 +532,7 @@ func Java_org_gioui_GioView_onStartView(env *C.JNIEnv, class C.jclass, handle C.
 func Java_org_gioui_GioView_onSurfaceDestroyed(env *C.JNIEnv, class C.jclass, handle C.jlong) {
 	w := cgo.Handle(handle).Value().(*window)
 	w.win = nil
-	w.setStage(StagePaused)
+	w.setStage(system.StagePaused)
 }
 
 //export Java_org_gioui_GioView_onSurfaceChanged
@@ -556,7 +554,7 @@ func Java_org_gioui_GioView_onLowMemory(env *C.JNIEnv, class C.jclass) {
 func Java_org_gioui_GioView_onConfigurationChanged(env *C.JNIEnv, class C.jclass, view C.jlong) {
 	w := cgo.Handle(view).Value().(*window)
 	w.loadConfig(env, class)
-	if w.stage >= StageInactive {
+	if w.stage >= system.StageInactive {
 		w.draw(env, true)
 	}
 }
@@ -567,7 +565,7 @@ func Java_org_gioui_GioView_onFrameCallback(env *C.JNIEnv, class C.jclass, view
 	if !exist {
 		return
 	}
-	if w.stage < StageInactive {
+	if w.stage < system.StageInactive {
 		return
 	}
 	if w.animating {
@@ -600,7 +598,7 @@ func Java_org_gioui_GioView_onWindowInsets(env *C.JNIEnv, class C.jclass, view C
 		left:   int(left),
 		right:  int(right),
 	}
-	if w.stage >= StageInactive {
+	if w.stage >= system.StageInactive {
 		w.draw(env, true)
 	}
 }
@@ -663,7 +661,7 @@ func Java_org_gioui_GioView_onClearA11yFocus(env *C.JNIEnv, class C.jclass, view
 	}
 }
 
-func (w *window) initAccessibilityNodeInfo(env *C.JNIEnv, sem input.SemanticNode, off image.Point, info C.jobject) error {
+func (w *window) initAccessibilityNodeInfo(env *C.JNIEnv, sem router.SemanticNode, off image.Point, info C.jobject) error {
 	for _, ch := range sem.Children {
 		err := callVoidMethod(env, info, android.accessibilityNodeInfo.addChild, jvalue(w.view), jvalue(w.virtualIDFor(ch.ID)))
 		if err != nil {
@@ -706,7 +704,7 @@ func (w *window) initAccessibilityNodeInfo(env *C.JNIEnv, sem input.SemanticNode
 			panic(err)
 		}
 	}
-	if d.Gestures&input.ClickGesture != 0 {
+	if d.Gestures&router.ClickGesture != 0 {
 		addAction(ACTION_CLICK)
 	}
 	clsName := android.strings.androidViewView
@@ -751,18 +749,19 @@ func (w *window) initAccessibilityNodeInfo(env *C.JNIEnv, sem input.SemanticNode
 	return nil
 }
 
-func (w *window) virtualIDFor(id input.SemanticID) C.jint {
+func (w *window) virtualIDFor(id router.SemanticID) C.jint {
+	// TODO: Android virtual IDs are 32-bit Java integers, but childID is a int64.
 	if id == w.semantic.rootID {
 		return HOST_VIEW_ID
 	}
 	return C.jint(id)
 }
 
-func (w *window) semIDFor(virtID C.jint) input.SemanticID {
+func (w *window) semIDFor(virtID C.jint) router.SemanticID {
 	if virtID == HOST_VIEW_ID {
 		return w.semantic.rootID
 	}
-	return input.SemanticID(virtID)
+	return router.SemanticID(virtID)
 }
 
 func (w *window) detach(env *C.JNIEnv) {
@@ -779,16 +778,16 @@ func (w *window) setVisible(env *C.JNIEnv) {
 	if width == 0 || height == 0 {
 		return
 	}
-	w.setStage(StageRunning)
+	w.setStage(system.StageRunning)
 	w.draw(env, true)
 }
 
-func (w *window) setStage(stage Stage) {
+func (w *window) setStage(stage system.Stage) {
 	if stage == w.stage {
 		return
 	}
 	w.stage = stage
-	w.callbacks.Event(StageEvent{stage})
+	w.callbacks.Event(system.StageEvent{stage})
 }
 
 func (w *window) setVisual(visID int) error {
@@ -838,14 +837,14 @@ func (w *window) draw(env *C.JNIEnv, sync bool) {
 	const inchPrDp = 1.0 / 160
 	ppdp := float32(w.dpi) * inchPrDp
 	dppp := unit.Dp(1.0 / ppdp)
-	insets := Insets{
+	insets := system.Insets{
 		Top:    unit.Dp(w.insets.top) * dppp,
 		Bottom: unit.Dp(w.insets.bottom) * dppp,
 		Left:   unit.Dp(w.insets.left) * dppp,
 		Right:  unit.Dp(w.insets.right) * dppp,
 	}
 	w.callbacks.Event(frameEvent{
-		FrameEvent: FrameEvent{
+		FrameEvent: system.FrameEvent{
 			Now:    time.Now(),
 			Size:   w.config.Size,
 			Insets: insets,
@@ -899,8 +898,8 @@ func runInJVM(jvm *C.JavaVM, f func(env *C.JNIEnv)) {
 	f(env)
 }
 
-func convertKeyCode(code C.jint) (key.Name, bool) {
+func convertKeyCode(code C.jint) (string, bool) {
-	var n key.Name
+	var n string
 	switch code {
 	case C.AKEYCODE_FORWARD_DEL:
 		n = key.NameDeleteForward
@@ -1297,9 +1296,9 @@ func newWindow(window *callbacks, options []Option) error {
 	return <-mainWindow.errs
 }
 
-func (w *window) WriteClipboard(mime string, s []byte) {
+func (w *window) WriteClipboard(s string) {
 	runInJVM(javaVM(), func(env *C.JNIEnv) {
-		jstr := javaString(env, string(s))
+		jstr := javaString(env, s)
 		callStaticVoidMethod(env, android.gioCls, android.mwriteClipboard,
 			jvalue(android.appCtx), jvalue(jstr))
 	})
@@ -1313,12 +1312,7 @@ func (w *window) ReadClipboard() {
 			return
 		}
 		content := goString(env, C.jstring(c))
-		w.callbacks.Event(transfer.DataEvent{
+		w.callbacks.Event(clipboard.Event{Text: content})
-			Type: "application/text",
-			Open: func() io.ReadCloser {
-				return io.NopCloser(strings.NewReader(content))
-			},
-		})
 	})
 }
 

app/os_ios.go

@@ -72,19 +72,17 @@ import "C"
 
 import (
 	"image"
-	"io"
 	"runtime"
 	"runtime/debug"
-	"strings"
 	"time"
 	"unicode/utf16"
 	"unsafe"
 
 	"gioui.org/f32"
+	"gioui.org/io/clipboard"
 	"gioui.org/io/key"
 	"gioui.org/io/pointer"
 	"gioui.org/io/system"
-	"gioui.org/io/transfer"
 	"gioui.org/unit"
 )
 
@@ -131,7 +129,7 @@ func onCreate(view, controller C.CFTypeRef) {
 	w.w.SetDriver(w)
 	views[view] = w
 	w.Configure(wopts.options)
-	w.w.Event(StageEvent{Stage: StagePaused})
+	w.w.Event(system.StageEvent{Stage: system.StagePaused})
 	w.w.Event(ViewEvent{ViewController: uintptr(controller)})
 }
 
@@ -149,7 +147,7 @@ func (w *window) draw(sync bool) {
 	wasVisible := w.visible
 	w.visible = true
 	if !wasVisible {
-		w.w.Event(StageEvent{Stage: StageRunning})
+		w.w.Event(system.StageEvent{Stage: system.StageRunning})
 	}
 	const inchPrDp = 1.0 / 163
 	m := unit.Metric{
@@ -158,13 +156,13 @@ func (w *window) draw(sync bool) {
 	}
 	dppp := unit.Dp(1. / m.PxPerDp)
 	w.w.Event(frameEvent{
-		FrameEvent: FrameEvent{
+		FrameEvent: system.FrameEvent{
 			Now: time.Now(),
 			Size: image.Point{
 				X: int(params.width + .5),
 				Y: int(params.height + .5),
 			},
-			Insets: Insets{
+			Insets: system.Insets{
 				Top:    unit.Dp(params.top) * dppp,
 				Bottom: unit.Dp(params.bottom) * dppp,
 				Left:   unit.Dp(params.left) * dppp,
@@ -180,7 +178,7 @@ func (w *window) draw(sync bool) {
 func onStop(view C.CFTypeRef) {
 	w := views[view]
 	w.visible = false
-	w.w.Event(StageEvent{Stage: StagePaused})
+	w.w.Event(system.StageEvent{Stage: system.StagePaused})
 }
 
 //export onDestroy
@@ -188,7 +186,7 @@ func onDestroy(view C.CFTypeRef) {
 	w := views[view]
 	delete(views, view)
 	w.w.Event(ViewEvent{})
-	w.w.Event(DestroyEvent{})
+	w.w.Event(system.DestroyEvent{})
 	w.displayLink.Close()
 	w.view = 0
 }
@@ -267,16 +265,11 @@ func (w *window) ReadClipboard() {
 	cstr := C.readClipboard()
 	defer C.CFRelease(cstr)
 	content := nsstringToString(cstr)
-	w.w.Event(transfer.DataEvent{
+	w.w.Event(clipboard.Event{Text: content})
-		Type: "application/text",
-		Open: func() io.ReadCloser {
-			return io.NopCloser(strings.NewReader(content))
-		},
-	})
 }
 
-func (w *window) WriteClipboard(mime string, s []byte) {
+func (w *window) WriteClipboard(s string) {
-	u16 := utf16.Encode([]rune(string(s)))
+	u16 := utf16.Encode([]rune(s))
 	var chars *C.unichar
 	if len(u16) > 0 {
 		chars = (*C.unichar)(unsafe.Pointer(&u16[0]))
@@ -310,7 +303,7 @@ func (w *window) SetCursor(cursor pointer.Cursor) {
 	w.cursor = windowSetCursor(w.cursor, cursor)
 }
 
-func (w *window) onKeyCommand(name key.Name) {
+func (w *window) onKeyCommand(name string) {
 	w.w.Event(key.Event{
 		Name: name,
 	})

app/os_js.go

@@ -6,7 +6,6 @@ import (
 	"fmt"
 	"image"
 	"image/color"
-	"io"
 	"strings"
 	"syscall/js"
 	"time"
@@ -16,10 +15,10 @@ import (
 	"gioui.org/internal/f32color"
 
 	"gioui.org/f32"
+	"gioui.org/io/clipboard"
 	"gioui.org/io/key"
 	"gioui.org/io/pointer"
 	"gioui.org/io/system"
-	"gioui.org/io/transfer"
 	"gioui.org/unit"
 )
 
@@ -102,12 +101,7 @@ func newWindow(win *callbacks, options []Option) error {
 	})
 	w.clipboardCallback = w.funcOf(func(this js.Value, args []js.Value) interface{} {
 		content := args[0].String()
-		go win.Event(transfer.DataEvent{
+		go win.Event(clipboard.Event{Text: content})
-			Type: "application/text",
-			Open: func() io.ReadCloser {
-				return io.NopCloser(strings.NewReader(content))
-			},
-		})
 		return nil
 	})
 	w.addEventListeners()
@@ -120,7 +114,7 @@ func newWindow(win *callbacks, options []Option) error {
 		w.Configure(options)
 		w.blur()
 		w.w.Event(ViewEvent{Element: cont})
-		w.w.Event(StageEvent{Stage: StageRunning})
+		w.w.Event(system.StageEvent{Stage: system.StageRunning})
 		w.resize()
 		w.draw(true)
 		for {
@@ -213,12 +207,12 @@ func (w *window) addEventListeners() {
 		return w.browserHistory.Call("back")
 	})
 	w.addEventListener(w.document, "visibilitychange", func(this js.Value, args []js.Value) interface{} {
-		ev := StageEvent{}
+		ev := system.StageEvent{}
 		switch w.document.Get("visibilityState").String() {
 		case "hidden", "prerender", "unloaded":
-			ev.Stage = StagePaused
+			ev.Stage = system.StagePaused
 		default:
-			ev.Stage = StageRunning
+			ev.Stage = system.StageRunning
 		}
 		w.w.Event(ev)
 		return nil
@@ -539,14 +533,14 @@ func (w *window) ReadClipboard() {
 	w.clipboard.Call("readText", w.clipboard).Call("then", w.clipboardCallback)
 }
 
-func (w *window) WriteClipboard(mime string, s []byte) {
+func (w *window) WriteClipboard(s string) {
 	if w.clipboard.IsUndefined() {
 		return
 	}
 	if w.clipboard.Get("writeText").IsUndefined() {
 		return
 	}
-	w.clipboard.Call("writeText", string(s))
+	w.clipboard.Call("writeText", s)
 }
 
 func (w *window) Configure(options []Option) {
@@ -672,7 +666,7 @@ func (w *window) draw(sync bool) {
 	}
 
 	w.w.Event(frameEvent{
-		FrameEvent: FrameEvent{
+		FrameEvent: system.FrameEvent{
 			Now:    time.Now(),
 			Size:   size,
 			Insets: insets,
@@ -682,10 +676,10 @@ func (w *window) draw(sync bool) {
 	})
 }
 
-func (w *window) getConfig() (image.Point, Insets, unit.Metric) {
+func (w *window) getConfig() (image.Point, system.Insets, unit.Metric) {
 	invscale := unit.Dp(1. / w.scale)
 	return image.Pt(w.config.Size.X, w.config.Size.Y),
-		Insets{
+		system.Insets{
 			Bottom: unit.Dp(w.inset.Y) * invscale,
 			Right:  unit.Dp(w.inset.X) * invscale,
 		}, unit.Metric{
@@ -752,8 +746,8 @@ func osMain() {
 	select {}
 }
 
-func translateKey(k string) (key.Name, bool) {
+func translateKey(k string) (string, bool) {
-	var n key.Name
+	var n string
 
 	switch k {
 	case "ArrowUp":
@@ -820,7 +814,7 @@ func translateKey(k string) (key.Name, bool) {
 		r, s := utf8.DecodeRuneInString(k)
 		// If there is exactly one printable character, return that.
 		if s == len(k) && unicode.IsPrint(r) {
-			return key.Name(strings.ToUpper(k)), true
+			return strings.ToUpper(k), true
 		}
 		return "", false
 	}

app/os_macos.go

@@ -8,18 +8,16 @@ package app
 import (
 	"errors"
 	"image"
-	"io"
 	"runtime"
-	"strings"
 	"time"
 	"unicode"
 	"unicode/utf8"
 
 	"gioui.org/internal/f32"
+	"gioui.org/io/clipboard"
 	"gioui.org/io/key"
 	"gioui.org/io/pointer"
 	"gioui.org/io/system"
-	"gioui.org/io/transfer"
 	"gioui.org/unit"
 
 	_ "gioui.org/internal/cocoainit"
@@ -249,7 +247,7 @@ type ViewEvent struct {
 type window struct {
 	view        C.CFTypeRef
 	w           *callbacks
-	stage       Stage
+	stage       system.Stage
 	displayLink *displayLink
 	// redraw is a single entry channel for making sure only one
 	// display link redraw request is in flight.
@@ -307,16 +305,11 @@ func (w *window) ReadClipboard() {
 		defer C.CFRelease(cstr)
 	}
 	content := nsstringToString(cstr)
-	w.w.Event(transfer.DataEvent{
+	w.w.Event(clipboard.Event{Text: content})
-		Type: "application/text",
-		Open: func() io.ReadCloser {
-			return io.NopCloser(strings.NewReader(content))
-		},
-	})
 }
 
-func (w *window) WriteClipboard(mime string, s []byte) {
+func (w *window) WriteClipboard(s string) {
-	cstr := stringToNSString(string(s))
+	cstr := stringToNSString(s)
 	defer C.CFRelease(cstr)
 	C.writeClipboard(cstr)
 }
@@ -488,12 +481,12 @@ func (w *window) runOnMain(f func()) {
 	})
 }
 
-func (w *window) setStage(stage Stage) {
+func (w *window) setStage(stage system.Stage) {
 	if stage == w.stage {
 		return
 	}
 	w.stage = stage
-	w.w.Event(StageEvent{Stage: stage})
+	w.w.Event(system.StageEvent{Stage: stage})
 }
 
 //export gio_onKeys
@@ -583,11 +576,11 @@ func gio_onDraw(view C.CFTypeRef) {
 func gio_onFocus(view C.CFTypeRef, focus C.int) {
 	w := mustView(view)
 	w.w.Event(key.FocusEvent{Focus: focus == 1})
-	if w.stage >= StageInactive {
+	if w.stage >= system.StageInactive {
 		if focus == 0 {
-			w.setStage(StageInactive)
+			w.setStage(system.StageInactive)
 		} else {
-			w.setStage(StageRunning)
+			w.setStage(system.StageRunning)
 		}
 	}
 	w.SetCursor(w.cursor)
@@ -782,9 +775,9 @@ func (w *window) draw() {
 		return
 	}
 	cfg := configFor(w.scale)
-	w.setStage(StageRunning)
+	w.setStage(system.StageRunning)
 	w.w.Event(frameEvent{
-		FrameEvent: FrameEvent{
+		FrameEvent: system.FrameEvent{
 			Now:    time.Now(),
 			Size:   w.config.Size,
 			Metric: cfg,
@@ -804,7 +797,7 @@ func configFor(scale float32) unit.Metric {
 func gio_onClose(view C.CFTypeRef) {
 	w := mustView(view)
 	w.w.Event(ViewEvent{})
-	w.w.Event(DestroyEvent{})
+	w.w.Event(system.DestroyEvent{})
 	w.displayLink.Close()
 	w.displayLink = nil
 	deleteView(view)
@@ -815,13 +808,13 @@ func gio_onClose(view C.CFTypeRef) {
 //export gio_onHide
 func gio_onHide(view C.CFTypeRef) {
 	w := mustView(view)
-	w.setStage(StagePaused)
+	w.setStage(system.StagePaused)
 }
 
 //export gio_onShow
 func gio_onShow(view C.CFTypeRef) {
 	w := mustView(view)
-	w.setStage(StageRunning)
+	w.setStage(system.StageRunning)
 }
 
 //export gio_onFullscreen
@@ -841,14 +834,14 @@ func gio_onWindowed(view C.CFTypeRef) {
 //export gio_onAppHide
 func gio_onAppHide() {
 	for _, w := range viewMap {
-		w.setStage(StagePaused)
+		w.setStage(system.StagePaused)
 	}
 }
 
 //export gio_onAppShow
 func gio_onAppShow() {
 	for _, w := range viewMap {
-		w.setStage(StageRunning)
+		w.setStage(system.StageRunning)
 	}
 }
 
@@ -920,8 +913,8 @@ func osMain() {
 	C.gio_main()
 }
 
-func convertKey(k rune) (key.Name, bool) {
+func convertKey(k rune) (string, bool) {
-	var n key.Name
+	var n string
 	switch k {
 	case 0x1b:
 		n = key.NameEscape
@@ -982,7 +975,7 @@ func convertKey(k rune) (key.Name, bool) {
 		if !unicode.IsPrint(k) {
 			return "", false
 		}
-		n = key.Name(k)
+		n = string(k)
 	}
 	return n, true
 }

app/os_wayland.go

@@ -25,10 +25,10 @@ import (
 	"gioui.org/app/internal/xkb"
 	"gioui.org/f32"
 	"gioui.org/internal/fling"
+	"gioui.org/io/clipboard"
 	"gioui.org/io/key"
 	"gioui.org/io/pointer"
 	"gioui.org/io/system"
-	"gioui.org/io/transfer"
 	"gioui.org/unit"
 )
 
@@ -194,7 +194,7 @@ type window struct {
 		dir            f32.Point
 	}
 
-	stage             Stage
+	stage             system.Stage
 	dead              bool
 	lastFrameCallback *C.struct_wl_callback
 
@@ -209,7 +209,7 @@ type window struct {
 	wsize        image.Point // window config size before going fullscreen or maximized
 	inCompositor bool        // window is moving or being resized
 
-	clipReads chan transfer.DataEvent
+	clipReads chan clipboard.Event
 
 	wakeups chan struct{}
 }
@@ -277,7 +277,7 @@ func newWLWindow(callbacks *callbacks, options []Option) error {
 
 		err := w.loop()
 		w.w.Event(WaylandViewEvent{})
-		w.w.Event(DestroyEvent{Err: err})
+		w.w.Event(system.DestroyEvent{Err: err})
 	}()
 	return nil
 }
@@ -354,7 +354,7 @@ func (d *wlDisplay) createNativeWindow(options []Option) (*window, error) {
 		ppdp:      ppdp,
 		ppsp:      ppdp,
 		wakeups:   make(chan struct{}, 1),
-		clipReads: make(chan transfer.DataEvent, 1),
+		clipReads: make(chan clipboard.Event, 1),
 	}
 	w.surf = C.wl_compositor_create_surface(d.compositor)
 	if w.surf == nil {
@@ -551,7 +551,7 @@ func gio_onXdgSurfaceConfigure(data unsafe.Pointer, wmSurf *C.struct_xdg_surface
 	w.serial = serial
 	w.redraw = true
 	C.xdg_surface_ack_configure(wmSurf, serial)
-	w.setStage(StageRunning)
+	w.setStage(system.StageRunning)
 }
 
 //export gio_onToplevelClose
@@ -1021,24 +1021,20 @@ func (w *window) ReadClipboard() {
 	r, err := w.disp.readClipboard()
 	// Send empty responses on unavailable clipboards or errors.
 	if r == nil || err != nil {
+		w.w.Event(clipboard.Event{})
 		return
 	}
 	// Don't let slow clipboard transfers block event loop.
 	go func() {
 		defer r.Close()
 		data, _ := io.ReadAll(r)
-		w.clipReads <- transfer.DataEvent{
+		w.clipReads <- clipboard.Event{Text: string(data)}
-			Type: "application/text",
-			Open: func() io.ReadCloser {
-				return io.NopCloser(bytes.NewReader(data))
-			},
-		}
 		w.Wakeup()
 	}()
 }
 
-func (w *window) WriteClipboard(mime string, s []byte) {
+func (w *window) WriteClipboard(s string) {
-	w.disp.writeClipboard(s)
+	w.disp.writeClipboard([]byte(s))
 }
 
 func (w *window) Configure(options []Option) {
@@ -1677,9 +1673,9 @@ func (w *window) updateOutputs() {
 		w.redraw = true
 	}
 	if !found {
-		w.setStage(StagePaused)
+		w.setStage(system.StagePaused)
 	} else {
-		w.setStage(StageRunning)
+		w.setStage(system.StageRunning)
 		w.redraw = true
 	}
 }
@@ -1716,7 +1712,7 @@ func (w *window) draw() {
 		C.wl_callback_add_listener(w.lastFrameCallback, &C.gio_callback_listener, unsafe.Pointer(w.surf))
 	}
 	w.w.Event(frameEvent{
-		FrameEvent: FrameEvent{
+		FrameEvent: system.FrameEvent{
 			Now:    time.Now(),
 			Size:   w.config.Size,
 			Metric: cfg,
@@ -1725,12 +1721,12 @@ func (w *window) draw() {
 	})
 }
 
-func (w *window) setStage(s Stage) {
+func (w *window) setStage(s system.Stage) {
 	if s == w.stage {
 		return
 	}
 	w.stage = s
-	w.w.Event(StageEvent{Stage: s})
+	w.w.Event(system.StageEvent{Stage: s})
 }
 
 func (w *window) display() *C.struct_wl_display {

app/os_windows.go

@@ -6,7 +6,6 @@ import (
 	"errors"
 	"fmt"
 	"image"
-	"io"
 	"runtime"
 	"sort"
 	"strings"
@@ -23,10 +22,10 @@ import (
 	gowindows "golang.org/x/sys/windows"
 
 	"gioui.org/f32"
+	"gioui.org/io/clipboard"
 	"gioui.org/io/key"
 	"gioui.org/io/pointer"
 	"gioui.org/io/system"
-	"gioui.org/io/transfer"
 )
 
 type ViewEvent struct {
@@ -37,7 +36,7 @@ type window struct {
 	hwnd        syscall.Handle
 	hdc         syscall.Handle
 	w           *callbacks
-	stage       Stage
+	stage       system.Stage
 	pointerBtns pointer.Buttons
 
 	// cursorIn tracks whether the cursor was inside the window according
@@ -269,11 +268,11 @@ func windowProc(hwnd syscall.Handle, msg uint32, wParam, lParam uintptr) uintptr
 		w.focused = false
 		w.w.Event(key.FocusEvent{Focus: false})
 	case windows.WM_NCACTIVATE:
-		if w.stage >= StageInactive {
+		if w.stage >= system.StageInactive {
 			if wParam == windows.TRUE {
-				w.setStage(StageRunning)
+				w.setStage(system.StageRunning)
 			} else {
-				w.setStage(StageInactive)
+				w.setStage(system.StageInactive)
 			}
 		}
 	case windows.WM_NCHITTEST:
@@ -302,7 +301,7 @@ func windowProc(hwnd syscall.Handle, msg uint32, wParam, lParam uintptr) uintptr
 		w.scrollEvent(wParam, lParam, true, getModifiers())
 	case windows.WM_DESTROY:
 		w.w.Event(ViewEvent{})
-		w.w.Event(DestroyEvent{})
+		w.w.Event(system.DestroyEvent{})
 		if w.hdc != 0 {
 			windows.ReleaseDC(w.hdc)
 			w.hdc = 0
@@ -339,15 +338,15 @@ func windowProc(hwnd syscall.Handle, msg uint32, wParam, lParam uintptr) uintptr
 		switch wParam {
 		case windows.SIZE_MINIMIZED:
 			w.config.Mode = Minimized
-			w.setStage(StagePaused)
+			w.setStage(system.StagePaused)
 		case windows.SIZE_MAXIMIZED:
 			w.config.Mode = Maximized
-			w.setStage(StageRunning)
+			w.setStage(system.StageRunning)
 		case windows.SIZE_RESTORED:
 			if w.config.Mode != Fullscreen {
 				w.config.Mode = Windowed
 			}
-			w.setStage(StageRunning)
+			w.setStage(system.StageRunning)
 		}
 	case windows.WM_GETMINMAXINFO:
 		mm := (*windows.MinMaxInfo)(unsafe.Pointer(uintptr(lParam)))
@@ -608,10 +607,10 @@ func (w *window) Wakeup() {
 	}
 }
 
-func (w *window) setStage(s Stage) {
+func (w *window) setStage(s system.Stage) {
 	if s != w.stage {
 		w.stage = s
-		w.w.Event(StageEvent{Stage: s})
+		w.w.Event(system.StageEvent{Stage: s})
 	}
 }
 
@@ -622,7 +621,7 @@ func (w *window) draw(sync bool) {
 	dpi := windows.GetWindowDPI(w.hwnd)
 	cfg := configForDPI(dpi)
 	w.w.Event(frameEvent{
-		FrameEvent: FrameEvent{
+		FrameEvent: system.FrameEvent{
 			Now:    time.Now(),
 			Size:   w.config.Size,
 			Metric: cfg,
@@ -668,12 +667,7 @@ func (w *window) readClipboard() error {
 	}
 	defer windows.GlobalUnlock(mem)
 	content := gowindows.UTF16PtrToString((*uint16)(unsafe.Pointer(ptr)))
-	w.w.Event(transfer.DataEvent{
+	w.w.Event(clipboard.Event{Text: content})
-		Type: "application/text",
-		Open: func() io.ReadCloser {
-			return io.NopCloser(strings.NewReader(content))
-		},
-	})
 	return nil
 }
 
@@ -741,8 +735,8 @@ func (w *window) Configure(options []Option) {
 	w.update()
 }
 
-func (w *window) WriteClipboard(mime string, s []byte) {
+func (w *window) WriteClipboard(s string) {
-	w.writeClipboard(string(s))
+	w.writeClipboard(s)
 }
 
 func (w *window) writeClipboard(s string) error {
@@ -870,11 +864,11 @@ func (w *window) raise() {
 		windows.SWP_NOMOVE|windows.SWP_NOSIZE|windows.SWP_SHOWWINDOW)
 }
 
-func convertKeyCode(code uintptr) (key.Name, bool) {
+func convertKeyCode(code uintptr) (string, bool) {
 	if '0' <= code && code <= '9' || 'A' <= code && code <= 'Z' {
-		return key.Name(rune(code)), true
+		return string(rune(code)), true
 	}
-	var r key.Name
+	var r string
 
 	switch code {
 	case windows.VK_ESCAPE:

app/os_x11.go

@@ -30,18 +30,16 @@ import (
 	"errors"
 	"fmt"
 	"image"
-	"io"
 	"strconv"
-	"strings"
 	"sync"
 	"time"
 	"unsafe"
 
 	"gioui.org/f32"
+	"gioui.org/io/clipboard"
 	"gioui.org/io/key"
 	"gioui.org/io/pointer"
 	"gioui.org/io/system"
-	"gioui.org/io/transfer"
 	"gioui.org/unit"
 
 	syscall "golang.org/x/sys/unix"
@@ -93,7 +91,7 @@ type x11Window struct {
 		// _NET_WM_STATE_MAXIMIZED_VERT
 		wmStateMaximizedVert C.Atom
 	}
-	stage  Stage
+	stage  system.Stage
 	metric unit.Metric
 	notify struct {
 		read, write int
@@ -153,8 +151,8 @@ func (w *x11Window) ReadClipboard() {
 	C.XConvertSelection(w.x, w.atoms.clipboard, w.atoms.utf8string, w.atoms.clipboardContent, w.xw, C.CurrentTime)
 }
 
-func (w *x11Window) WriteClipboard(mime string, s []byte) {
+func (w *x11Window) WriteClipboard(s string) {
-	w.clipboard.content = s
+	w.clipboard.content = []byte(s)
 	C.XSetSelectionOwner(w.x, w.atoms.clipboard, w.xw, C.CurrentTime)
 	C.XSetSelectionOwner(w.x, w.atoms.primary, w.xw, C.CurrentTime)
 }
@@ -395,12 +393,12 @@ func (w *x11Window) window() (C.Window, int, int) {
 	return w.xw, w.config.Size.X, w.config.Size.Y
 }
 
-func (w *x11Window) setStage(s Stage) {
+func (w *x11Window) setStage(s system.Stage) {
 	if s == w.stage {
 		return
 	}
 	w.stage = s
-	w.w.Event(StageEvent{Stage: s})
+	w.w.Event(system.StageEvent{Stage: s})
 }
 
 func (w *x11Window) loop() {
@@ -460,7 +458,7 @@ loop:
 
 		if (anim || syn) && w.config.Size.X != 0 && w.config.Size.Y != 0 {
 			w.w.Event(frameEvent{
-				FrameEvent: FrameEvent{
+				FrameEvent: system.FrameEvent{
 					Now:    time.Now(),
 					Size:   w.config.Size,
 					Metric: w.metric,
@@ -652,12 +650,7 @@ func (h *x11EventHandler) handleEvents() bool {
 				break
 			}
 			str := C.GoStringN((*C.char)(unsafe.Pointer(text.value)), C.int(text.nitems))
-			w.w.Event(transfer.DataEvent{
+			w.w.Event(clipboard.Event{Text: str})
-				Type: "application/text",
-				Open: func() io.ReadCloser {
-					return io.NopCloser(strings.NewReader(str))
-				},
-			})
 		case C.SelectionRequest:
 			cevt := (*C.XSelectionRequestEvent)(unsafe.Pointer(xev))
 			if (cevt.selection != w.atoms.clipboard && cevt.selection != w.atoms.primary) || cevt.property == C.None {
@@ -837,10 +830,10 @@ func newX11Window(gioWin *callbacks, options []Option) error {
 		C.XMapWindow(dpy, win)
 		w.Configure(options)
 		w.w.Event(X11ViewEvent{Display: unsafe.Pointer(dpy), Window: uintptr(win)})
-		w.setStage(StageRunning)
+		w.setStage(system.StageRunning)
 		w.loop()
 		w.w.Event(X11ViewEvent{})
-		w.w.Event(DestroyEvent{Err: nil})
+		w.w.Event(system.DestroyEvent{Err: nil})
 		w.destroy()
 	}()
 	return nil

app/system.go

@@ -1,49 +0,0 @@
-// SPDX-License-Identifier: Unlicense OR MIT
-
-package app
-
-// DestroyEvent is the last event sent through
-// a window event channel.
-type DestroyEvent struct {
-	// Err is nil for normal window closures. If a
-	// window is prematurely closed, Err is the cause.
-	Err error
-}
-
-// A StageEvent is generated whenever the stage of a
-// Window changes.
-type StageEvent struct {
-	Stage Stage
-}
-
-// Stage of a Window.
-type Stage uint8
-
-const (
-	// StagePaused is the stage for windows that have no on-screen representation.
-	// Paused windows don't receive frames.
-	StagePaused Stage = iota
-	// StageInactive is the stage for windows that are visible, but not active.
-	// Inactive windows receive frames.
-	StageInactive
-	// StageRunning is for active and visible Windows.
-	// Running windows receive frames.
-	StageRunning
-)
-
-// String implements fmt.Stringer.
-func (l Stage) String() string {
-	switch l {
-	case StagePaused:
-		return "StagePaused"
-	case StageInactive:
-		return "StageInactive"
-	case StageRunning:
-		return "StageRunning"
-	default:
-		panic("unexpected Stage value")
-	}
-}
-
-func (StageEvent) ImplementsEvent()   {}
-func (DestroyEvent) ImplementsEvent() {}

app/window.go

@@ -19,9 +19,10 @@ import (
 	"gioui.org/internal/debug"
 	"gioui.org/internal/ops"
 	"gioui.org/io/event"
-	"gioui.org/io/input"
 	"gioui.org/io/key"
 	"gioui.org/io/pointer"
+	"gioui.org/io/profile"
+	"gioui.org/io/router"
 	"gioui.org/io/system"
 	"gioui.org/layout"
 	"gioui.org/op"
@@ -67,7 +68,7 @@ type Window struct {
 	frameAck chan struct{}
 	destroy  chan struct{}
 
-	stage        Stage
+	stage        system.Stage
 	animating    bool
 	hasNextFrame bool
 	nextFrame    time.Time
@@ -76,7 +77,7 @@ type Window struct {
 	// metric is the metric from the most recent frame.
 	metric unit.Metric
 
-	queue       input.Router
+	queue       queue
 	cursor      pointer.Cursor
 	decorations struct {
 		op.Ops
@@ -101,10 +102,10 @@ type Window struct {
 	semantic struct {
 		// uptodate tracks whether the fields below are up to date.
 		uptodate bool
-		root     input.SemanticID
+		root     router.SemanticID
-		prevTree []input.SemanticNode
+		prevTree []router.SemanticNode
-		tree     []input.SemanticNode
+		tree     []router.SemanticNode
-		ids      map[input.SemanticID]input.SemanticNode
+		ids      map[router.SemanticID]router.SemanticNode
 	}
 
 	imeState editorState
@@ -121,7 +122,7 @@ type Window struct {
 }
 
 type editorState struct {
-	input.EditorState
+	router.EditorState
 	compose key.Range
 }
 
@@ -132,6 +133,12 @@ type callbacks struct {
 	waitEvents []event.Event
 }
 
+// queue is an event.Queue implementation that distributes system events
+// to the input handlers declared in the most recent frame.
+type queue struct {
+	q router.Router
+}
+
 // NewWindow creates a new window for a set of window
 // options. The options are hints; the platform is free to
 // ignore or adjust them.
@@ -188,7 +195,7 @@ func NewWindow(options ...Option) *Window {
 	w.decorations.enabled = cnf.Decorated
 	w.decorations.height = decoHeight
 	w.imeState.compose = key.Range{Start: -1, End: -1}
-	w.semantic.ids = make(map[input.SemanticID]input.SemanticNode)
+	w.semantic.ids = make(map[router.SemanticID]router.SemanticNode)
 	w.callbacks.w = w
 	w.eventState.initialOpts = options
 	return w
@@ -273,7 +280,7 @@ func (w *Window) validateAndProcess(d driver, size image.Point, sync bool, frame
 				return err
 			}
 		}
-		w.queue.Frame(frame)
+		w.queue.q.Frame(frame)
 		// Let the client continue as soon as possible, in particular before
 		// a potentially blocking Present.
 		signal()
@@ -301,25 +308,25 @@ func (w *Window) frame(frame *op.Ops, viewport image.Point) error {
 	return w.gpu.Frame(frame, target, viewport)
 }
 
-func (w *Window) processFrame(d driver) {
+func (w *Window) processFrame(d driver, frameStart time.Time) {
 	for k := range w.semantic.ids {
 		delete(w.semantic.ids, k)
 	}
 	w.semantic.uptodate = false
-	q := &w.queue
+	q := &w.queue.q
 	switch q.TextInputState() {
-	case input.TextInputOpen:
+	case router.TextInputOpen:
 		d.ShowTextInput(true)
-	case input.TextInputClose:
+	case router.TextInputClose:
 		d.ShowTextInput(false)
 	}
 	if hint, ok := q.TextInputHint(); ok {
 		d.SetInputHint(hint)
 	}
-	if mime, txt, ok := q.WriteClipboard(); ok {
+	if txt, ok := q.WriteClipboard(); ok {
-		d.WriteClipboard(mime, txt)
+		d.WriteClipboard(txt)
 	}
-	if q.ClipboardRequested() {
+	if q.ReadClipboard() {
 		d.ReadClipboard()
 	}
 	oldState := w.imeState
@@ -329,18 +336,25 @@ func (w *Window) processFrame(d driver) {
 		w.imeState = newState
 		d.EditorStateChanged(oldState, newState)
 	}
+	if q.Profiling() && w.gpu != nil {
+		frameDur := time.Since(frameStart)
+		frameDur = frameDur.Truncate(100 * time.Microsecond)
+		quantum := 100 * time.Microsecond
+		timings := fmt.Sprintf("tot:%7s %s", frameDur.Round(quantum), w.gpu.Profile())
+		q.Queue(profile.Event{Timings: timings})
+	}
 	if t, ok := q.WakeupTime(); ok {
 		w.setNextFrame(t)
 	}
 	w.updateAnimation(d)
 }
 
-// Invalidate the window such that a [FrameEvent] will be generated immediately.
+// Invalidate the window such that a FrameEvent will be generated immediately.
 // If the window is inactive, the event is sent when the window becomes active.
 //
 // Note that Invalidate is intended for externally triggered updates, such as a
-// response from a network request. The [op.InvalidateCmd] command is more efficient
+// response from a network request. InvalidateOp is more efficient for animation
-// for animation.
+// and similar internal updates.
 //
 // Invalidate is safe for concurrent use.
 func (w *Window) Invalidate() {
@@ -372,14 +386,21 @@ func (w *Window) Option(opts ...Option) {
 	}
 }
 
+// WriteClipboard writes a string to the clipboard.
+func (w *Window) WriteClipboard(s string) {
+	w.driverDefer(func(d driver) {
+		d.WriteClipboard(s)
+	})
+}
+
 // Run f in the same thread as the native window event loop, and wait for f to
 // return or the window to close. Run is guaranteed not to deadlock if it is
-// invoked during the handling of a [ViewEvent], [FrameEvent],
+// invoked during the handling of a ViewEvent, system.FrameEvent,
-// [StageEvent]; call Run in a separate goroutine to avoid deadlock in all
+// system.StageEvent; call Run in a separate goroutine to avoid deadlock in all
 // other cases.
 //
 // Note that most programs should not call Run; configuring a Window with
-// [CustomRenderer] is a notable exception.
+// CustomRenderer is a notable exception.
 func (w *Window) Run(f func()) {
 	done := make(chan struct{})
 	w.driverDefer(func(d driver) {
@@ -404,7 +425,7 @@ func (w *Window) driverDefer(f func(d driver)) {
 
 func (w *Window) updateAnimation(d driver) {
 	animate := false
-	if w.stage >= StageInactive && w.hasNextFrame {
+	if w.stage >= system.StageInactive && w.hasNextFrame {
 		if dt := time.Until(w.nextFrame); dt <= 0 {
 			animate = true
 		} else {
@@ -494,19 +515,19 @@ func (c *callbacks) Event(e event.Event) bool {
 }
 
 // SemanticRoot returns the ID of the semantic root.
-func (c *callbacks) SemanticRoot() input.SemanticID {
+func (c *callbacks) SemanticRoot() router.SemanticID {
 	c.w.updateSemantics()
 	return c.w.semantic.root
 }
 
 // LookupSemantic looks up a semantic node from an ID. The zero ID denotes the root.
-func (c *callbacks) LookupSemantic(semID input.SemanticID) (input.SemanticNode, bool) {
+func (c *callbacks) LookupSemantic(semID router.SemanticID) (router.SemanticNode, bool) {
 	c.w.updateSemantics()
 	n, found := c.w.semantic.ids[semID]
 	return n, found
 }
 
-func (c *callbacks) AppendSemanticDiffs(diffs []input.SemanticID) []input.SemanticID {
+func (c *callbacks) AppendSemanticDiffs(diffs []router.SemanticID) []router.SemanticID {
 	c.w.updateSemantics()
 	if tree := c.w.semantic.prevTree; len(tree) > 0 {
 		c.w.collectSemanticDiffs(&diffs, c.w.semantic.prevTree[0])
@@ -514,9 +535,9 @@ func (c *callbacks) AppendSemanticDiffs(diffs []input.SemanticID) []input.Semant
 	return diffs
 }
 
-func (c *callbacks) SemanticAt(pos f32.Point) (input.SemanticID, bool) {
+func (c *callbacks) SemanticAt(pos f32.Point) (router.SemanticID, bool) {
 	c.w.updateSemantics()
-	return c.w.queue.SemanticAt(pos)
+	return c.w.queue.q.SemanticAt(pos)
 }
 
 func (c *callbacks) EditorState() editorState {
@@ -558,38 +579,37 @@ func (c *callbacks) SetEditorSnippet(r key.Range) {
 	c.Event(key.SnippetEvent(r))
 }
 
-func (w *Window) moveFocus(dir key.FocusDirection) {
+func (w *Window) moveFocus(dir router.FocusDirection, d driver) {
-	w.queue.MoveFocus(dir)
+	if w.queue.q.MoveFocus(dir) {
-	if _, handled := w.queue.WakeupTime(); handled {
+		w.queue.q.RevealFocus(w.viewport)
-		w.queue.RevealFocus(w.viewport)
 	} else {
 		var v image.Point
 		switch dir {
-		case key.FocusRight:
+		case router.FocusRight:
 			v = image.Pt(+1, 0)
-		case key.FocusLeft:
+		case router.FocusLeft:
 			v = image.Pt(-1, 0)
-		case key.FocusDown:
+		case router.FocusDown:
 			v = image.Pt(0, +1)
-		case key.FocusUp:
+		case router.FocusUp:
 			v = image.Pt(0, -1)
 		default:
 			return
 		}
 		const scrollABit = unit.Dp(50)
 		dist := v.Mul(int(w.metric.Dp(scrollABit)))
-		w.queue.ScrollFocus(dist)
+		w.queue.q.ScrollFocus(dist)
 	}
 }
 
 func (c *callbacks) ClickFocus() {
-	c.w.queue.ClickFocus()
+	c.w.queue.q.ClickFocus()
 	c.w.setNextFrame(time.Time{})
 	c.w.updateAnimation(c.d)
 }
 
 func (c *callbacks) ActionAt(p f32.Point) (system.Action, bool) {
-	return c.w.queue.ActionAt(p)
+	return c.w.queue.q.ActionAt(p)
 }
 
 func (e *editorState) Replace(r key.Range, text string) {
@@ -724,7 +744,7 @@ func (w *Window) destroyGPU() {
 	}
 }
 
-// waitFrame waits for the client to either call [FrameEvent.Frame]
+// waitFrame waits for the client to either call FrameEvent.Frame
 // or to continue event handling.
 func (w *Window) waitFrame(d driver) *op.Ops {
 	for {
@@ -753,7 +773,7 @@ func (w *Window) updateSemantics() {
 	}
 	w.semantic.uptodate = true
 	w.semantic.prevTree, w.semantic.tree = w.semantic.tree, w.semantic.prevTree
-	w.semantic.tree = w.queue.AppendSemantics(w.semantic.tree[:0])
+	w.semantic.tree = w.queue.q.AppendSemantics(w.semantic.tree[:0])
 	w.semantic.root = w.semantic.tree[0].ID
 	for _, n := range w.semantic.tree {
 		w.semantic.ids[n.ID] = n
@@ -761,7 +781,7 @@ func (w *Window) updateSemantics() {
 }
 
 // collectSemanticDiffs traverses the previous semantic tree, noting changed nodes.
-func (w *Window) collectSemanticDiffs(diffs *[]input.SemanticID, n input.SemanticNode) {
+func (w *Window) collectSemanticDiffs(diffs *[]router.SemanticID, n router.SemanticNode) {
 	newNode, exists := w.semantic.ids[n.ID]
 	// Ignore deleted nodes, as their disappearance will be reported through an
 	// ancestor node.
@@ -802,8 +822,8 @@ func (w *Window) processEvent(d driver, e event.Event) bool {
 	default:
 	}
 	switch e2 := e.(type) {
-	case StageEvent:
+	case system.StageEvent:
-		if e2.Stage < StageInactive {
+		if e2.Stage < system.StageInactive {
 			if w.gpu != nil {
 				w.ctx.Lock()
 				w.gpu.Release()
@@ -819,14 +839,18 @@ func (w *Window) processEvent(d driver, e event.Event) bool {
 		if e2.Size == (image.Point{}) {
 			panic(errors.New("internal error: zero-sized Draw"))
 		}
-		if w.stage < StageInactive {
+		if w.stage < system.StageInactive {
 			// No drawing if not visible.
 			break
 		}
 		w.metric = e2.Metric
+		var frameStart time.Time
+		if w.queue.q.Profiling() {
+			frameStart = time.Now()
+		}
 		w.hasNextFrame = false
 		e2.Frame = w.update
-		e2.Source = w.queue.Source()
+		e2.Queue = &w.queue
 
 		// Prepare the decorations and update the frame insets.
 		wrapper := &w.decorations.Ops
@@ -843,7 +867,7 @@ func (w *Window) processEvent(d driver, e event.Event) bool {
 		}
 		// Scroll to focus if viewport is shrinking in any dimension.
 		if old, new := w.viewport.Size(), viewport.Size(); new.X < old.X || new.Y < old.Y {
-			w.queue.RevealFocus(viewport)
+			w.queue.q.RevealFocus(viewport)
 		}
 		w.viewport = viewport
 		viewSize := e2.Size
@@ -863,13 +887,13 @@ func (w *Window) processEvent(d driver, e event.Event) bool {
 		deco.Add(wrapper)
 		if err := w.validateAndProcess(d, viewSize, e2.Sync, wrapper, signal); err != nil {
 			w.destroyGPU()
-			w.out <- DestroyEvent{Err: err}
+			w.out <- system.DestroyEvent{Err: err}
 			close(w.destroy)
 			break
 		}
-		w.processFrame(d)
+		w.processFrame(d, frameStart)
 		w.updateCursor(d)
-	case DestroyEvent:
+	case system.DestroyEvent:
 		w.destroyGPU()
 		w.out <- e2
 		close(w.destroy)
@@ -882,37 +906,37 @@ func (w *Window) processEvent(d driver, e event.Event) bool {
 		w.out <- e2
 	case wakeupEvent:
 	case event.Event:
-		focusDir := key.FocusDirection(-1)
+		handled := w.queue.q.Queue(e2)
-		if e, ok := e2.(key.Event); ok && e.State == key.Press {
+		if e, ok := e.(key.Event); ok && !handled {
-			isMobile := runtime.GOOS == "ios" || runtime.GOOS == "android"
+			if e.State == key.Press {
-			switch {
+				handled = true
-			case e.Name == key.NameTab && e.Modifiers == 0:
+				isMobile := runtime.GOOS == "ios" || runtime.GOOS == "android"
-				focusDir = key.FocusForward
+				switch {
-			case e.Name == key.NameTab && e.Modifiers == key.ModShift:
+				case e.Name == key.NameTab && e.Modifiers == 0:
-				focusDir = key.FocusBackward
+					w.moveFocus(router.FocusForward, d)
-			case e.Name == key.NameUpArrow && e.Modifiers == 0 && isMobile:
+				case e.Name == key.NameTab && e.Modifiers == key.ModShift:
-				focusDir = key.FocusUp
+					w.moveFocus(router.FocusBackward, d)
-			case e.Name == key.NameDownArrow && e.Modifiers == 0 && isMobile:
+				case e.Name == key.NameUpArrow && e.Modifiers == 0 && isMobile:
-				focusDir = key.FocusDown
+					w.moveFocus(router.FocusUp, d)
-			case e.Name == key.NameLeftArrow && e.Modifiers == 0 && isMobile:
+				case e.Name == key.NameDownArrow && e.Modifiers == 0 && isMobile:
-				focusDir = key.FocusLeft
+					w.moveFocus(router.FocusDown, d)
-			case e.Name == key.NameRightArrow && e.Modifiers == 0 && isMobile:
+				case e.Name == key.NameLeftArrow && e.Modifiers == 0 && isMobile:
-				focusDir = key.FocusRight
+					w.moveFocus(router.FocusLeft, d)
+				case e.Name == key.NameRightArrow && e.Modifiers == 0 && isMobile:
+					w.moveFocus(router.FocusRight, d)
+				default:
+					handled = false
+				}
+			}
+			// As a special case, the top-most input handler receives all unhandled
+			// events.
+			if !handled {
+				handled = w.queue.q.QueueTopmost(e)
 			}
-		}
-		e := e2
-		if focusDir != -1 {
-			e = input.SystemEvent{Event: e}
-		}
-		w.queue.Queue(e)
-		t, handled := w.queue.WakeupTime()
-		if focusDir != -1 && !handled {
-			w.moveFocus(focusDir)
-			t, handled = w.queue.WakeupTime()
 		}
 		w.updateCursor(d)
 		if handled {
-			w.setNextFrame(t)
+			w.setNextFrame(time.Time{})
 			w.updateAnimation(d)
 		}
 		return handled
@@ -921,7 +945,7 @@ func (w *Window) processEvent(d driver, e event.Event) bool {
 }
 
 // NextEvent blocks until an event is received from the window, such as
-// [FrameEvent]. It blocks forever if called after [DestroyEvent]
+// [io/system.FrameEvent]. It blocks forever if called after [io/system.DestroyEvent]
 // has been returned.
 func (w *Window) NextEvent() event.Event {
 	state := &w.eventState
@@ -929,7 +953,7 @@ func (w *Window) NextEvent() event.Event {
 		state.created = true
 		if err := newWindow(&w.callbacks, state.initialOpts); err != nil {
 			close(w.destroy)
-			return DestroyEvent{Err: err}
+			return system.DestroyEvent{Err: err}
 		}
 	}
 	for {
@@ -970,7 +994,7 @@ func (w *Window) NextEvent() event.Event {
 }
 
 func (w *Window) updateCursor(d driver) {
-	if c := w.queue.Cursor(); c != w.cursor {
+	if c := w.queue.q.Cursor(); c != w.cursor {
 		w.cursor = c
 		d.SetCursor(c)
 	}
@@ -982,7 +1006,7 @@ func (w *Window) fallbackDecorate() bool {
 }
 
 // decorate the window if enabled and returns the corresponding Insets.
-func (w *Window) decorate(d driver, e FrameEvent, o *op.Ops) (size, offset image.Point) {
+func (w *Window) decorate(d driver, e system.FrameEvent, o *op.Ops) (size, offset image.Point) {
 	if !w.fallbackDecorate() {
 		return e.Size, image.Pt(0, 0)
 	}
@@ -1008,7 +1032,7 @@ func (w *Window) decorate(d driver, e FrameEvent, o *op.Ops) (size, offset image
 	gtx := layout.Context{
 		Ops:         o,
 		Now:         e.Now,
-		Source:      e.Source,
+		Queue:       e.Queue,
 		Metric:      e.Metric,
 		Constraints: layout.Exact(e.Size),
 	}
@@ -1061,6 +1085,10 @@ func (w *Window) Perform(actions system.Action) {
 	}
 }
 
+func (q *queue) Events(k event.Tag) []event.Event {
+	return q.q.Events(k)
+}
+
 // Title sets the title of the window.
 func Title(t string) Option {
 	return func(_ unit.Metric, cnf *Config) {

flake.lock

@@ -9,11 +9,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1701721028,
+        "lastModified": 1659298920,
-        "narHash": "sha256-2z4YrdHPLoMZNWR1MPOjNZMqPg057i1eZXaYI6RTahQ=",
+        "narHash": "sha256-LgRMge8BZUG15EN43iDJOlnEMX1dvRprB7SaoNqgibU=",
         "owner": "tadfisher",
         "repo": "android-nixpkgs",
-        "rev": "c923f9ec0f4dd0d7dc725dc5b73fbf03658e50dd",
+        "rev": "d4f20a3cd4ce961bb23b48447457f6810d69ae5e",
         "type": "github"
       },
       "original": {
@@ -24,18 +24,21 @@
     },
     "devshell": {
       "inputs": {
-        "nixpkgs": [
+        "flake-utils": [
           "android",
           "nixpkgs"
         ],
-        "systems": "systems"
+        "nixpkgs": [
+          "android",
+          "nixpkgs"
+        ]
       },
       "locked": {
-        "lastModified": 1701697687,
+        "lastModified": 1658746384,
-        "narHash": "sha256-dLLE5wQBVv+pIb4bWmKFSw2DvLVyuEk0F7ng6hpZPSU=",
+        "narHash": "sha256-CCJcoMOcXyZFrV1ag4XMTpAPjLWb4Anbv+ktXFI1ry0=",
         "owner": "numtide",
         "repo": "devshell",
-        "rev": "c3bd77911391eb1638af6ce773de86da57ee6df5",
+        "rev": "0ffc7937bb5e8141af03d462b468bd071eb18e1b",
         "type": "github"
       },
       "original": {
@@ -45,15 +48,12 @@
       }
     },
     "flake-utils": {
-      "inputs": {
-        "systems": "systems_2"
-      },
       "locked": {
-        "lastModified": 1701680307,
+        "lastModified": 1656928814,
-        "narHash": "sha256-kAuep2h5ajznlPMD9rnQyffWG8EM/C73lejGofXvdM8=",
+        "narHash": "sha256-RIFfgBuKz6Hp89yRr7+NR5tzIAbn52h8vT6vXkYjZoM=",
         "owner": "numtide",
         "repo": "flake-utils",
-        "rev": "4022d587cbbfd70fe950c1e2083a02621806a725",
+        "rev": "7e2a3b3dfd9af950a856d66b0a7d01e3c18aa249",
         "type": "github"
       },
       "original": {
@@ -64,16 +64,15 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1701282334,
+        "lastModified": 1659305579,
-        "narHash": "sha256-MxCVrXY6v4QmfTwIysjjaX0XUhqBbxTWWB4HXtDYsdk=",
+        "narHash": "sha256-SFeQTmh7hc9Y2fSkooHaoS8mDfPa04sfmUCtQ8MA6Pg=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "057f9aecfb71c4437d2b27d3323df7f93c010b7e",
+        "rev": "5857574d45925585baffde730369414319228a84",
         "type": "github"
       },
       "original": {
         "owner": "NixOS",
-        "ref": "23.11",
         "repo": "nixpkgs",
         "type": "github"
       }
@@ -83,36 +82,6 @@
         "android": "android",
         "nixpkgs": "nixpkgs"
       }
-    },
-    "systems": {
-      "locked": {
-        "lastModified": 1681028828,
-        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
-        "owner": "nix-systems",
-        "repo": "default",
-        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
-        "type": "github"
-      },
-      "original": {
-        "owner": "nix-systems",
-        "repo": "default",
-        "type": "github"
-      }
-    },
-    "systems_2": {
-      "locked": {
-        "lastModified": 1681028828,
-        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
-        "owner": "nix-systems",
-        "repo": "default",
-        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
-        "type": "github"
-      },
-      "original": {
-        "owner": "nix-systems",
-        "repo": "default",
-        "type": "github"
-      }
     }
   },
   "root": "root",

flake.nix

@@ -3,7 +3,7 @@
   description = "Gio build environment";
 
   inputs = {
-    nixpkgs.url = "github:NixOS/nixpkgs/23.11";
+    nixpkgs.url = "github:NixOS/nixpkgs";
     android.url = "github:tadfisher/android-nixpkgs";
     android.inputs.nixpkgs.follows = "nixpkgs";
   };
@@ -33,10 +33,10 @@
             default = with pkgs; mkShell
               ({
                 ANDROID_SDK_ROOT = "${android-sdk}/share/android-sdk";
-                JAVA_HOME = jdk17.home;
+                JAVA_HOME = jdk8.home;
                 packages = [
                   android-sdk
-                  jdk17
+                  jdk8
                   clang
                 ] ++ (if stdenv.isLinux then [
                   vulkan-headers
@@ -46,7 +46,7 @@
                   xorg.libXcursor
                   xorg.libXfixes
                   libGL
-                  pkg-config
+                  pkgconfig
                 ] else if stdenv.isDarwin then [
                   darwin.apple_sdk_11_0.frameworks.Foundation
                   darwin.apple_sdk_11_0.frameworks.Metal

gesture/gesture.go

@@ -18,7 +18,6 @@ import (
 	"gioui.org/f32"
 	"gioui.org/internal/fling"
 	"gioui.org/io/event"
-	"gioui.org/io/input"
 	"gioui.org/io/key"
 	"gioui.org/io/pointer"
 	"gioui.org/op"
@@ -38,19 +37,15 @@ type Hover struct {
 
 // Add the gesture to detect hovering over the current pointer area.
 func (h *Hover) Add(ops *op.Ops) {
-	event.Op(ops, h)
+	pointer.InputOp{
+		Tag:   h,
+		Kinds: pointer.Enter | pointer.Leave,
+	}.Add(ops)
 }
 
 // Update state and report whether a pointer is inside the area.
-func (h *Hover) Update(q input.Source) bool {
+func (h *Hover) Update(q event.Queue) bool {
-	for {
+	for _, ev := range q.Events(h) {
-		ev, ok := q.Event(pointer.Filter{
-			Target: h,
-			Kinds:  pointer.Enter | pointer.Leave | pointer.Cancel,
-		})
-		if !ok {
-			break
-		}
 		e, ok := ev.(pointer.Event)
 		if !ok {
 			continue
@@ -112,6 +107,7 @@ type Drag struct {
 	pressed  bool
 	pid      pointer.ID
 	start    f32.Point
+	grab     bool
 }
 
 // Scroll detects scroll gestures and reduces them to
@@ -119,9 +115,11 @@ type Drag struct {
 // movements as well as drag and fling touch gestures.
 type Scroll struct {
 	dragging  bool
+	axis      Axis
 	estimator fling.Extrapolation
 	flinger   fling.Animation
 	pid       pointer.ID
+	grab      bool
 	last      int
 	// Leftover scroll.
 	scroll float32
@@ -163,7 +161,10 @@ const touchSlop = unit.Dp(3)
 
 // Add the handler to the operation list to receive click events.
 func (c *Click) Add(ops *op.Ops) {
-	event.Op(ops, c)
+	pointer.InputOp{
+		Tag:   c,
+		Kinds: pointer.Press | pointer.Release | pointer.Enter | pointer.Leave,
+	}.Add(ops)
 }
 
 // Hovered returns whether a pointer is inside the area.
@@ -176,16 +177,10 @@ func (c *Click) Pressed() bool {
 	return c.pressed
 }
 
-// Update state and return the next click events, if any.
+// Update state and return the click events.
-func (c *Click) Update(q input.Source) (ClickEvent, bool) {
+func (c *Click) Update(q event.Queue) []ClickEvent {
-	for {
+	var events []ClickEvent
-		evt, ok := q.Event(pointer.Filter{
+	for _, evt := range q.Events(c) {
-			Target: c,
-			Kinds:  pointer.Press | pointer.Release | pointer.Enter | pointer.Leave | pointer.Cancel,
-		})
-		if !ok {
-			break
-		}
 		e, ok := evt.(pointer.Event)
 		if !ok {
 			continue
@@ -197,15 +192,9 @@ func (c *Click) Update(q input.Source) (ClickEvent, bool) {
 			}
 			c.pressed = false
 			if !c.entered || c.hovered {
-				return ClickEvent{
+				events = append(events, ClickEvent{Kind: KindClick, Position: e.Position.Round(), Source: e.Source, Modifiers: e.Modifiers, NumClicks: c.clicks})
-					Kind:      KindClick,
-					Position:  e.Position.Round(),
-					Source:    e.Source,
-					Modifiers: e.Modifiers,
-					NumClicks: c.clicks,
-				}, true
 			} else {
-				return ClickEvent{Kind: KindCancel}, true
+				events = append(events, ClickEvent{Kind: KindCancel})
 			}
 		case pointer.Cancel:
 			wasPressed := c.pressed
@@ -213,7 +202,7 @@ func (c *Click) Update(q input.Source) (ClickEvent, bool) {
 			c.hovered = false
 			c.entered = false
 			if wasPressed {
-				return ClickEvent{Kind: KindCancel}, true
+				events = append(events, ClickEvent{Kind: KindCancel})
 			}
 		case pointer.Press:
 			if c.pressed {
@@ -235,7 +224,7 @@ func (c *Click) Update(q input.Source) (ClickEvent, bool) {
 				c.clicks = 1
 			}
 			c.clickedAt = e.Time
-			return ClickEvent{Kind: KindPress, Position: e.Position.Round(), Source: e.Source, Modifiers: e.Modifiers, NumClicks: c.clicks}, true
+			events = append(events, ClickEvent{Kind: KindPress, Position: e.Position.Round(), Source: e.Source, Modifiers: e.Modifiers, NumClicks: c.clicks})
 		case pointer.Leave:
 			if !c.pressed {
 				c.pid = e.PointerID
@@ -253,16 +242,25 @@ func (c *Click) Update(q input.Source) (ClickEvent, bool) {
 			}
 		}
 	}
-	return ClickEvent{}, false
+	return events
 }
 
 func (ClickEvent) ImplementsEvent() {}
 
 // Add the handler to the operation list to receive scroll events.
 // The bounds variable refers to the scrolling boundaries
-// as defined in [pointer.Filter].
+// as defined in io/pointer.InputOp.
-func (s *Scroll) Add(ops *op.Ops) {
+func (s *Scroll) Add(ops *op.Ops, bounds image.Rectangle) {
-	event.Op(ops, s)
+	oph := pointer.InputOp{
+		Tag:          s,
+		Grab:         s.grab,
+		Kinds:        pointer.Press | pointer.Drag | pointer.Release | pointer.Scroll,
+		ScrollBounds: bounds,
+	}
+	oph.Add(ops)
+	if s.flinger.Active() {
+		op.InvalidateOp{}.Add(ops)
+	}
 }
 
 // Stop any remaining fling movement.
@@ -271,18 +269,13 @@ func (s *Scroll) Stop() {
 }
 
 // Update state and report the scroll distance along axis.
-func (s *Scroll) Update(cfg unit.Metric, q input.Source, t time.Time, axis Axis, bounds image.Rectangle) int {
+func (s *Scroll) Update(cfg unit.Metric, q event.Queue, t time.Time, axis Axis) int {
-	total := 0
+	if s.axis != axis {
-	f := pointer.Filter{
+		s.axis = axis
-		Target:       s,
+		return 0
-		Kinds:        pointer.Press | pointer.Drag | pointer.Release | pointer.Scroll | pointer.Cancel,
-		ScrollBounds: bounds,
 	}
-	for {
+	total := 0
-		evt, ok := q.Event(f)
+	for _, evt := range q.Events(s) {
-		if !ok {
-			break
-		}
 		e, ok := evt.(pointer.Event)
 		if !ok {
 			continue
@@ -299,7 +292,7 @@ func (s *Scroll) Update(cfg unit.Metric, q input.Source, t time.Time, axis Axis,
 			}
 			s.Stop()
 			s.estimator = fling.Extrapolation{}
-			v := s.val(axis, e.Position)
+			v := s.val(e.Position)
 			s.last = int(math.Round(float64(v)))
 			s.estimator.Sample(e.Time, v)
 			s.dragging = true
@@ -315,8 +308,9 @@ func (s *Scroll) Update(cfg unit.Metric, q input.Source, t time.Time, axis Axis,
 			fallthrough
 		case pointer.Cancel:
 			s.dragging = false
+			s.grab = false
 		case pointer.Scroll:
-			switch axis {
+			switch s.axis {
 			case Horizontal:
 				s.scroll += e.Scroll.X
 			case Vertical:
@@ -329,14 +323,14 @@ func (s *Scroll) Update(cfg unit.Metric, q input.Source, t time.Time, axis Axis,
 			if !s.dragging || s.pid != e.PointerID {
 				continue
 			}
-			val := s.val(axis, e.Position)
+			val := s.val(e.Position)
 			s.estimator.Sample(e.Time, val)
 			v := int(math.Round(float64(val)))
 			dist := s.last - v
 			if e.Priority < pointer.Grabbed {
 				slop := cfg.Dp(touchSlop)
 				if dist := dist; dist >= slop || -slop >= dist {
-					q.Execute(pointer.GrabCmd{Tag: s, ID: e.PointerID})
+					s.grab = true
 				}
 			} else {
 				s.last = v
@@ -345,14 +339,11 @@ func (s *Scroll) Update(cfg unit.Metric, q input.Source, t time.Time, axis Axis,
 		}
 	}
 	total += s.flinger.Tick(t)
-	if s.flinger.Active() {
-		q.Execute(op.InvalidateCmd{})
-	}
 	return total
 }
 
-func (s *Scroll) val(axis Axis, p f32.Point) float32 {
+func (s *Scroll) val(p f32.Point) float32 {
-	if axis == Horizontal {
+	if s.axis == Horizontal {
 		return p.X
 	} else {
 		return p.Y
@@ -373,20 +364,18 @@ func (s *Scroll) State() ScrollState {
 
 // Add the handler to the operation list to receive drag events.
 func (d *Drag) Add(ops *op.Ops) {
-	event.Op(ops, d)
+	pointer.InputOp{
+		Tag:   d,
+		Grab:  d.grab,
+		Kinds: pointer.Press | pointer.Drag | pointer.Release,
+	}.Add(ops)
 }
 
-// Update state and return the next drag event, if any.
+// Update state and return the drag events.
-func (d *Drag) Update(cfg unit.Metric, q input.Source, axis Axis) (pointer.Event, bool) {
+func (d *Drag) Update(cfg unit.Metric, q event.Queue, axis Axis) []pointer.Event {
-	for {
+	var events []pointer.Event
-		ev, ok := q.Event(pointer.Filter{
+	for _, e := range q.Events(d) {
-			Target: d,
+		e, ok := e.(pointer.Event)
-			Kinds:  pointer.Press | pointer.Drag | pointer.Release | pointer.Cancel,
-		})
-		if !ok {
-			break
-		}
-		e, ok := ev.(pointer.Event)
 		if !ok {
 			continue
 		}
@@ -419,7 +408,7 @@ func (d *Drag) Update(cfg unit.Metric, q input.Source, axis Axis) (pointer.Event
 				diff := e.Position.Sub(d.start)
 				slop := cfg.Dp(touchSlop)
 				if diff.X*diff.X+diff.Y*diff.Y > float32(slop*slop) {
-					q.Execute(pointer.GrabCmd{Tag: d, ID: e.PointerID})
+					d.grab = true
 				}
 			}
 		case pointer.Release, pointer.Cancel:
@@ -428,12 +417,13 @@ func (d *Drag) Update(cfg unit.Metric, q input.Source, axis Axis) (pointer.Event
 				continue
 			}
 			d.dragging = false
+			d.grab = false
 		}
 
-		return e, true
+		events = append(events, e)
 	}
 
-	return pointer.Event{}, false
+	return events
 }
 
 // Dragging reports whether it is currently in use.

gesture/gesture_test.go

@@ -9,8 +9,8 @@ import (
 
 	"gioui.org/f32"
 	"gioui.org/io/event"
-	"gioui.org/io/input"
 	"gioui.org/io/pointer"
+	"gioui.org/io/router"
 	"gioui.org/op"
 	"gioui.org/op/clip"
 )
@@ -22,21 +22,20 @@ func TestHover(t *testing.T) {
 	stack := clip.Rect(rect).Push(ops)
 	h.Add(ops)
 	stack.Pop()
-	r := new(input.Router)
+	r := new(router.Router)
-	h.Update(r.Source())
 	r.Frame(ops)
 
 	r.Queue(
 		pointer.Event{Kind: pointer.Move, Position: f32.Pt(30, 30)},
 	)
-	if !h.Update(r.Source()) {
+	if !h.Update(r) {
 		t.Fatal("expected hovered")
 	}
 
 	r.Queue(
 		pointer.Event{Kind: pointer.Move, Position: f32.Pt(50, 50)},
 	)
-	if h.Update(r.Source()) {
+	if h.Update(r) {
 		t.Fatal("expected not hovered")
 	}
 }
@@ -72,21 +71,12 @@ func TestMouseClicks(t *testing.T) {
 			var ops op.Ops
 			click.Add(&ops)
 
-			var r input.Router
+			var r router.Router
-			click.Update(r.Source())
 			r.Frame(&ops)
 			r.Queue(tc.events...)
 
-			var clicks []ClickEvent
+			events := click.Update(&r)
-			for {
+			clicks := filterMouseClicks(events)
-				ev, ok := click.Update(r.Source())
-				if !ok {
-					break
-				}
-				if ev.Kind == KindClick {
-					clicks = append(clicks, ev)
-				}
-			}
 			if got, want := len(clicks), len(tc.clicks); got != want {
 				t.Fatalf("got %d mouse clicks, expected %d", got, want)
 			}
@@ -116,3 +106,13 @@ func mouseClickEvents(times ...time.Duration) []event.Event {
 	}
 	return events
 }
+
+func filterMouseClicks(events []ClickEvent) []ClickEvent {
+	var clicks []ClickEvent
+	for _, ev := range events {
+		if ev.Kind == KindClick {
+			clicks = append(clicks, ev)
+		}
+	}
+	return clicks
+}

gpu/caches.go

@@ -8,13 +8,8 @@ import (
 	"gioui.org/internal/f32"
 )
 
-type textureCacheKey struct {
+type resourceCache struct {
-	filter byte
+	res map[interface{}]resourceCacheValue
-	handle any
-}
-
-type textureCache struct {
-	res map[textureCacheKey]resourceCacheValue
 }
 
 type resourceCacheValue struct {
@@ -42,13 +37,13 @@ type opCacheValue struct {
 	keep bool
 }
 
-func newTextureCache() *textureCache {
+func newResourceCache() *resourceCache {
-	return &textureCache{
+	return &resourceCache{
-		res: make(map[textureCacheKey]resourceCacheValue),
+		res: make(map[interface{}]resourceCacheValue),
 	}
 }
 
-func (r *textureCache) get(key textureCacheKey) (resource, bool) {
+func (r *resourceCache) get(key interface{}) (resource, bool) {
 	v, exists := r.res[key]
 	if !exists {
 		return nil, false
@@ -60,17 +55,17 @@ func (r *textureCache) get(key textureCacheKey) (resource, bool) {
 	return v.resource, exists
 }
 
-func (r *textureCache) put(key textureCacheKey, val resource) {
+func (r *resourceCache) put(key interface{}, val resource) {
 	v, exists := r.res[key]
 	if exists && v.used {
-		panic(fmt.Errorf("key exists, %v", key))
+		panic(fmt.Errorf("key exists, %p", key))
 	}
 	v.used = true
 	v.resource = val
 	r.res[key] = v
 }
 
-func (r *textureCache) frame() {
+func (r *resourceCache) frame() {
 	for k, v := range r.res {
 		if v.used {
 			v.used = false
@@ -82,7 +77,7 @@ func (r *textureCache) frame() {
 	}
 }
 
-func (r *textureCache) release() {
+func (r *resourceCache) release() {
 	for _, v := range r.res {
 		v.resource.release()
 	}

gpu/caches_test.go

@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package gpu
+
+import "testing"
+
+func BenchmarkResourceCache(b *testing.B) {
+	offset := 0
+	const N = 100
+
+	cache := newResourceCache()
+	for i := 0; i < b.N; i++ {
+		// half are the same and half updated
+		for k := 0; k < N; k++ {
+			cache.put(offset+k, nullResource{})
+		}
+		cache.frame()
+		offset += N / 2
+	}
+}
+
+type nullResource struct{}
+
+func (nullResource) release() {}

gpu/compute.go

@@ -93,6 +93,7 @@ type compute struct {
 		}
 	}
 	timers struct {
+		profile string
 		t       *timers
 		compact *timer
 		render  *timer
@@ -175,6 +176,7 @@ type materialUniforms struct {
 
 type collector struct {
 	hasher     maphash.Hash
+	profile    bool
 	reader     ops.Reader
 	states     []f32.Affine2D
 	clear      bool
@@ -595,7 +597,7 @@ func (g *compute) frame(target RenderTarget) error {
 	defer g.ctx.EndFrame()
 
 	t := &g.timers
-	if false && t.t == nil && g.ctx.Caps().Features.Has(driver.FeatureTimers) {
+	if g.collector.profile && t.t == nil && g.ctx.Caps().Features.Has(driver.FeatureTimers) {
 		t.t = newTimers(g.ctx)
 		t.compact = t.t.newTimer()
 		t.render = t.t.newTimer()
@@ -629,13 +631,13 @@ func (g *compute) frame(target RenderTarget) error {
 		return err
 	}
 	t.compact.end()
-	if false && t.t.ready() {
+	if g.collector.profile && t.t.ready() {
 		com, ren, blit := t.compact.Elapsed, t.render.Elapsed, t.blit.Elapsed
 		ft := com + ren + blit
 		q := 100 * time.Microsecond
 		ft = ft.Round(q)
 		com, ren, blit = com.Round(q), ren.Round(q), blit.Round(q)
-		// t.profile = fmt.Sprintf("ft:%7s com: %7s ren:%7s blit:%7s", ft, com, ren, blit)
+		t.profile = fmt.Sprintf("ft:%7s com: %7s ren:%7s blit:%7s", ft, com, ren, blit)
 	}
 	return nil
 }
@@ -659,6 +661,10 @@ func (g *compute) dumpAtlases() {
 	}
 }
 
+func (g *compute) Profile() string {
+	return g.timers.profile
+}
+
 func (g *compute) compactAllocs() error {
 	const (
 		maxAllocAge = 3
@@ -1650,6 +1656,7 @@ func (e *encoder) line(start, end f32.Point) {
 
 func (c *collector) reset() {
 	c.prevFrame, c.frame = c.frame, c.prevFrame
+	c.profile = false
 	c.clipStates = c.clipStates[:0]
 	c.transStack = c.transStack[:0]
 	c.frame.reset()
@@ -1729,6 +1736,8 @@ func (c *collector) collect(root *op.Ops, viewport image.Point, texOps *[]textur
 	c.addClip(&state, fview, fview, nil, ops.Key{}, 0, 0, false)
 	for encOp, ok := r.Decode(); ok; encOp, ok = r.Decode() {
 		switch ops.OpType(encOp.Data[0]) {
+		case ops.TypeProfile:
+			c.profile = true
 		case ops.TypeTransform:
 			dop, push := ops.DecodeTransform(encOp.Data)
 			if push {

gpu/gpu.go

@@ -44,10 +44,14 @@ type GPU interface {
 	Clear(color color.NRGBA)
 	// Frame draws the graphics operations from op into a viewport of target.
 	Frame(frame *op.Ops, target RenderTarget, viewport image.Point) error
+	// Profile returns the last available profiling information. Profiling
+	// information is requested when Frame sees an io/profile.Op, and the result
+	// is available through Profile at some later time.
+	Profile() string
 }
 
 type gpu struct {
-	cache *textureCache
+	cache *resourceCache
 
 	profile                                string
 	timers                                 *timers
@@ -69,6 +73,7 @@ type renderer struct {
 }
 
 type drawOps struct {
+	profile      bool
 	reader       ops.Reader
 	states       []f32.Affine2D
 	transStack   []f32.Affine2D
@@ -354,7 +359,7 @@ func NewWithDevice(d driver.Device) (GPU, error) {
 
 func newGPU(ctx driver.Device) (*gpu, error) {
 	g := &gpu{
-		cache: newTextureCache(),
+		cache: newResourceCache(),
 	}
 	g.drawOps.pathCache = newOpCache()
 	if err := g.init(ctx); err != nil {
@@ -394,7 +399,7 @@ func (g *gpu) collect(viewport image.Point, frameOps *op.Ops) {
 	g.renderer.pather.viewport = viewport
 	g.drawOps.reset(viewport)
 	g.drawOps.collect(frameOps, viewport)
-	if false && g.timers == nil && g.ctx.Caps().Features.Has(driver.FeatureTimers) {
+	if g.drawOps.profile && g.timers == nil && g.ctx.Caps().Features.Has(driver.FeatureTimers) {
 		g.frameStart = time.Now()
 		g.timers = newTimers(g.ctx)
 		g.stencilTimer = g.timers.newTimer()
@@ -420,9 +425,9 @@ func (g *gpu) frame(target RenderTarget) error {
 	g.stencilTimer.end()
 	g.coverTimer.begin()
 	g.renderer.uploadImages(g.cache, g.drawOps.imageOps)
-	g.renderer.prepareDrawOps(g.drawOps.imageOps)
+	g.renderer.prepareDrawOps(g.cache, g.drawOps.imageOps)
 	g.drawOps.layers = g.renderer.packLayers(g.drawOps.layers)
-	g.renderer.drawLayers(g.drawOps.layers, g.drawOps.imageOps)
+	g.renderer.drawLayers(g.cache, g.drawOps.layers, g.drawOps.imageOps)
 	d := driver.LoadDesc{
 		ClearColor: g.drawOps.clearColor,
 	}
@@ -432,14 +437,14 @@ func (g *gpu) frame(target RenderTarget) error {
 	}
 	g.ctx.BeginRenderPass(defFBO, d)
 	g.ctx.Viewport(0, 0, viewport.X, viewport.Y)
-	g.renderer.drawOps(false, image.Point{}, g.renderer.blitter.viewport, g.drawOps.imageOps)
+	g.renderer.drawOps(g.cache, false, image.Point{}, g.renderer.blitter.viewport, g.drawOps.imageOps)
 	g.coverTimer.end()
 	g.ctx.EndRenderPass()
 	g.cleanupTimer.begin()
 	g.cache.frame()
 	g.drawOps.pathCache.frame()
 	g.cleanupTimer.end()
-	if false && g.timers.ready() {
+	if g.drawOps.profile && g.timers.ready() {
 		st, covt, cleant := g.stencilTimer.Elapsed, g.coverTimer.Elapsed, g.cleanupTimer.Elapsed
 		ft := st + covt + cleant
 		q := 100 * time.Microsecond
@@ -455,8 +460,12 @@ func (g *gpu) Profile() string {
 	return g.profile
 }
 
-func (r *renderer) texHandle(cache *textureCache, data imageOpData) driver.Texture {
+func (r *renderer) texHandle(cache *resourceCache, data imageOpData) driver.Texture {
-	key := textureCacheKey{
+	type cachekey struct {
+		filter byte
+		handle any
+	}
+	key := cachekey{
 		filter: data.filter,
 		handle: data.handle,
 	}
@@ -844,7 +853,7 @@ func (r *renderer) packLayers(layers []opacityLayer) []opacityLayer {
 	return layers
 }
 
-func (r *renderer) drawLayers(layers []opacityLayer, ops []imageOp) {
+func (r *renderer) drawLayers(cache *resourceCache, layers []opacityLayer, ops []imageOp) {
 	if len(r.layers.sizes) == 0 {
 		return
 	}
@@ -867,7 +876,7 @@ func (r *renderer) drawLayers(layers []opacityLayer, ops []imageOp) {
 		}
 		r.ctx.Viewport(v.Min.X, v.Min.Y, v.Max.X, v.Max.Y)
 		f := r.layerFBOs.fbos[fbo]
-		r.drawOps(true, l.clip.Min.Mul(-1), l.clip.Size(), ops[l.opStart:l.opEnd])
+		r.drawOps(cache, true, l.clip.Min.Mul(-1), l.clip.Size(), ops[l.opStart:l.opEnd])
 		sr := f32.FRect(v)
 		uvScale, uvOffset := texSpaceTransform(sr, f.size)
 		uvTrans := f32.Affine2D{}.Scale(f32.Point{}, uvScale).Offset(uvOffset)
@@ -890,6 +899,7 @@ func (r *renderer) drawLayers(layers []opacityLayer, ops []imageOp) {
 }
 
 func (d *drawOps) reset(viewport image.Point) {
+	d.profile = false
 	d.viewport = viewport
 	d.imageOps = d.imageOps[:0]
 	d.pathOps = d.pathOps[:0]
@@ -983,6 +993,8 @@ func (d *drawOps) collectOps(r *ops.Reader, viewport f32.Rectangle) {
 loop:
 	for encOp, ok := r.Decode(); ok; encOp, ok = r.Decode() {
 		switch ops.OpType(encOp.Data[0]) {
+		case ops.TypeProfile:
+			d.profile = true
 		case ops.TypeTransform:
 			dop, push := ops.DecodeTransform(encOp.Data)
 			if push {
@@ -1199,7 +1211,7 @@ func (d *drawState) materialFor(rect f32.Rectangle, off f32.Point, partTrans f32
 	return m
 }
 
-func (r *renderer) uploadImages(cache *textureCache, ops []imageOp) {
+func (r *renderer) uploadImages(cache *resourceCache, ops []imageOp) {
 	for i := range ops {
 		img := &ops[i]
 		m := img.material
@@ -1209,7 +1221,7 @@ func (r *renderer) uploadImages(cache *textureCache, ops []imageOp) {
 	}
 }
 
-func (r *renderer) prepareDrawOps(ops []imageOp) {
+func (r *renderer) prepareDrawOps(cache *resourceCache, ops []imageOp) {
 	for _, img := range ops {
 		m := img.material
 		switch m.material {
@@ -1230,7 +1242,7 @@ func (r *renderer) prepareDrawOps(ops []imageOp) {
 	}
 }
 
-func (r *renderer) drawOps(isFBO bool, opOff image.Point, viewport image.Point, ops []imageOp) {
+func (r *renderer) drawOps(cache *resourceCache, isFBO bool, opOff image.Point, viewport image.Point, ops []imageOp) {
 	var coverTex driver.Texture
 	for i := 0; i < len(ops); i++ {
 		img := ops[i]

internal/gl/gl_unix.go

@@ -665,7 +665,7 @@ func (f *Functions) load(forceES bool) error {
 	case runtime.GOOS == "android":
 		libNames = []string{"libGLESv2.so", "libGLESv3.so"}
 	default:
-		libNames = []string{"libGLESv2.so.2", "libGLESv2.so.3.0"}
+		libNames = []string{"libGLESv2.so.2"}
 	}
 	for _, lib := range libNames {
 		if h := dlopen(lib); h != nil {

internal/ops/ops.go

@@ -55,19 +55,28 @@ const (
 	TypePopTransform
 	TypePushOpacity
 	TypePopOpacity
+	TypeInvalidate
 	TypeImage
 	TypePaint
 	TypeColor
 	TypeLinearGradient
 	TypePass
 	TypePopPass
-	TypeInput
+	TypePointerInput
-	TypeKeyInputHint
+	TypeClipboardRead
+	TypeClipboardWrite
+	TypeSource
+	TypeTarget
+	TypeOffer
+	TypeKeyInput
+	TypeKeyFocus
+	TypeKeySoftKeyboard
 	TypeSave
 	TypeLoad
 	TypeAux
 	TypeClip
 	TypePopClip
+	TypeProfile
 	TypeCursor
 	TypePath
 	TypeStroke
@@ -76,6 +85,8 @@ const (
 	TypeSemanticClass
 	TypeSemanticSelected
 	TypeSemanticEnabled
+	TypeSnippet
+	TypeSelection
 	TypeActionInput
 )
 
@@ -137,13 +148,21 @@ const (
 	TypeLinearGradientLen   = 1 + 8*2 + 4*2
 	TypePassLen             = 1
 	TypePopPassLen          = 1
-	TypeInputLen            = 1
+	TypePointerInputLen     = 1 + 1 + 1*2 + 2*4 + 2*4
-	TypeKeyInputHintLen     = 1 + 1
+	TypeClipboardReadLen    = 1
+	TypeClipboardWriteLen   = 1
+	TypeSourceLen           = 1
+	TypeTargetLen           = 1
+	TypeOfferLen            = 1
+	TypeKeyInputLen         = 1 + 1
+	TypeKeyFocusLen         = 1 + 1
+	TypeKeySoftKeyboardLen  = 1 + 1
 	TypeSaveLen             = 1 + 4
 	TypeLoadLen             = 1 + 4
 	TypeAuxLen              = 1
 	TypeClipLen             = 1 + 4*4 + 1 + 1
 	TypePopClipLen          = 1
+	TypeProfileLen          = 1
 	TypeCursorLen           = 2
 	TypePathLen             = 8 + 1
 	TypeStrokeLen           = 1 + 4
@@ -152,6 +171,8 @@ const (
 	TypeSemanticClassLen    = 2
 	TypeSemanticSelectedLen = 2
 	TypeSemanticEnabledLen  = 2
+	TypeSnippetLen          = 1 + 4 + 4
+	TypeSelectionLen        = 1 + 2*4 + 2*4 + 4 + 4
 	TypeActionInputLen      = 1 + 1
 )
 
@@ -404,19 +425,28 @@ var opProps = [0x100]opProp{
 	TypePopTransform:     {Size: TypePopTransformLen, NumRefs: 0},
 	TypePushOpacity:      {Size: TypePushOpacityLen, NumRefs: 0},
 	TypePopOpacity:       {Size: TypePopOpacityLen, NumRefs: 0},
+	TypeInvalidate:       {Size: TypeRedrawLen, NumRefs: 0},
 	TypeImage:            {Size: TypeImageLen, NumRefs: 2},
 	TypePaint:            {Size: TypePaintLen, NumRefs: 0},
 	TypeColor:            {Size: TypeColorLen, NumRefs: 0},
 	TypeLinearGradient:   {Size: TypeLinearGradientLen, NumRefs: 0},
 	TypePass:             {Size: TypePassLen, NumRefs: 0},
 	TypePopPass:          {Size: TypePopPassLen, NumRefs: 0},
-	TypeInput:            {Size: TypeInputLen, NumRefs: 1},
+	TypePointerInput:     {Size: TypePointerInputLen, NumRefs: 1},
-	TypeKeyInputHint:     {Size: TypeKeyInputHintLen, NumRefs: 1},
+	TypeClipboardRead:    {Size: TypeClipboardReadLen, NumRefs: 1},
+	TypeClipboardWrite:   {Size: TypeClipboardWriteLen, NumRefs: 1},
+	TypeSource:           {Size: TypeSourceLen, NumRefs: 2},
+	TypeTarget:           {Size: TypeTargetLen, NumRefs: 2},
+	TypeOffer:            {Size: TypeOfferLen, NumRefs: 3},
+	TypeKeyInput:         {Size: TypeKeyInputLen, NumRefs: 2},
+	TypeKeyFocus:         {Size: TypeKeyFocusLen, NumRefs: 1},
+	TypeKeySoftKeyboard:  {Size: TypeKeySoftKeyboardLen, NumRefs: 0},
 	TypeSave:             {Size: TypeSaveLen, NumRefs: 0},
 	TypeLoad:             {Size: TypeLoadLen, NumRefs: 0},
 	TypeAux:              {Size: TypeAuxLen, NumRefs: 0},
 	TypeClip:             {Size: TypeClipLen, NumRefs: 0},
 	TypePopClip:          {Size: TypePopClipLen, NumRefs: 0},
+	TypeProfile:          {Size: TypeProfileLen, NumRefs: 1},
 	TypeCursor:           {Size: TypeCursorLen, NumRefs: 0},
 	TypePath:             {Size: TypePathLen, NumRefs: 0},
 	TypeStroke:           {Size: TypeStrokeLen, NumRefs: 0},
@@ -425,6 +455,8 @@ var opProps = [0x100]opProp{
 	TypeSemanticClass:    {Size: TypeSemanticClassLen, NumRefs: 0},
 	TypeSemanticSelected: {Size: TypeSemanticSelectedLen, NumRefs: 0},
 	TypeSemanticEnabled:  {Size: TypeSemanticEnabledLen, NumRefs: 0},
+	TypeSnippet:          {Size: TypeSnippetLen, NumRefs: 2},
+	TypeSelection:        {Size: TypeSelectionLen, NumRefs: 1},
 	TypeActionInput:      {Size: TypeActionInputLen, NumRefs: 0},
 }
 
@@ -457,6 +489,8 @@ func (t OpType) String() string {
 		return "PushOpacity"
 	case TypePopOpacity:
 		return "PopOpacity"
+	case TypeInvalidate:
+		return "Invalidate"
 	case TypeImage:
 		return "Image"
 	case TypePaint:
@@ -469,10 +503,24 @@ func (t OpType) String() string {
 		return "Pass"
 	case TypePopPass:
 		return "PopPass"
-	case TypeInput:
+	case TypePointerInput:
-		return "Input"
+		return "PointerInput"
-	case TypeKeyInputHint:
+	case TypeClipboardRead:
-		return "KeyInputHint"
+		return "ClipboardRead"
+	case TypeClipboardWrite:
+		return "ClipboardWrite"
+	case TypeSource:
+		return "Source"
+	case TypeTarget:
+		return "Target"
+	case TypeOffer:
+		return "Offer"
+	case TypeKeyInput:
+		return "KeyInput"
+	case TypeKeyFocus:
+		return "KeyFocus"
+	case TypeKeySoftKeyboard:
+		return "KeySoftKeyboard"
 	case TypeSave:
 		return "Save"
 	case TypeLoad:
@@ -483,6 +531,8 @@ func (t OpType) String() string {
 		return "Clip"
 	case TypePopClip:
 		return "PopClip"
+	case TypeProfile:
+		return "Profile"
 	case TypeCursor:
 		return "Cursor"
 	case TypePath:

io/clipboard/clipboard.go

@@ -3,22 +3,35 @@
 package clipboard
 
 import (
-	"io"
+	"gioui.org/internal/ops"
-
 	"gioui.org/io/event"
+	"gioui.org/op"
 )
 
-// WriteCmd copies Text to the clipboard.
+// Event is generated when the clipboard content is requested.
-type WriteCmd struct {
+type Event struct {
-	Type string
+	Text string
-	Data io.ReadCloser
 }
 
-// ReadCmd requests the text of the clipboard, delivered to
+// ReadOp requests the text of the clipboard, delivered to
-// the handler through an [io/transfer.DataEvent].
+// the current handler through an Event.
-type ReadCmd struct {
+type ReadOp struct {
 	Tag event.Tag
 }
 
-func (WriteCmd) ImplementsCommand() {}
+// WriteOp copies Text to the clipboard.
-func (ReadCmd) ImplementsCommand()  {}
+type WriteOp struct {
+	Text string
+}
+
+func (h ReadOp) Add(o *op.Ops) {
+	data := ops.Write1(&o.Internal, ops.TypeClipboardReadLen, h.Tag)
+	data[0] = byte(ops.TypeClipboardRead)
+}
+
+func (h WriteOp) Add(o *op.Ops) {
+	data := ops.Write1String(&o.Internal, ops.TypeClipboardWriteLen, h.Text)
+	data[0] = byte(ops.TypeClipboardWrite)
+}
+
+func (Event) ImplementsEvent() {}

io/event/event.go

@@ -1,12 +1,41 @@
 // SPDX-License-Identifier: Unlicense OR MIT
 
-// Package event contains types for event handling.
+/*
+Package event contains the types for event handling.
+
+The Queue interface is the protocol for receiving external events.
+
+For example:
+
+	var queue event.Queue = ...
+
+	for _, e := range queue.Events(h) {
+		switch e.(type) {
+			...
+		}
+	}
+
+In general, handlers must be declared before events become
+available. Other packages such as pointer and key provide
+the means for declaring handlers for specific event types.
+
+The following example declares a handler ready for key input:
+
+	import gioui.org/io/key
+
+	ops := new(op.Ops)
+	var h *Handler = ...
+	key.InputOp{Tag: h, Filter: ...}.Add(ops)
+*/
 package event
 
-import (
+// Queue maps an event handler key to the events
-	"gioui.org/internal/ops"
+// available to the handler.
-	"gioui.org/op"
+type Queue interface {
-)
+	// Events returns the available events for an
+	// event handler tag.
+	Events(t Tag) []Event
+}
 
 // Tag is the stable identifier for an event handler.
 // For a handler h, the tag is typically &h.
@@ -16,18 +45,3 @@ type Tag interface{}
 type Event interface {
 	ImplementsEvent()
 }
-
-// Filter represents a filter for [Event] types.
-type Filter interface {
-	ImplementsFilter()
-}
-
-// Op declares a tag for input routing at the current transformation
-// and clip area hierarchy. It panics if tag is nil.
-func Op(o *op.Ops, tag Tag) {
-	if tag == nil {
-		panic("Tag must be non-nil")
-	}
-	data := ops.Write1(&o.Internal, ops.TypeInputLen, tag)
-	data[0] = byte(ops.TypeInput)
-}

io/input/clipboard.go

@@ -1,72 +0,0 @@
-// SPDX-License-Identifier: Unlicense OR MIT
-
-package input
-
-import (
-	"io"
-
-	"gioui.org/io/clipboard"
-	"gioui.org/io/event"
-)
-
-// clipboardState contains the state for clipboard event routing.
-type clipboardState struct {
-	receivers []event.Tag
-}
-
-type clipboardQueue struct {
-	// request avoid read clipboard every frame while waiting.
-	requested bool
-	mime      string
-	text      []byte
-}
-
-// WriteClipboard returns the most recent data to be copied
-// to the clipboard, if any.
-func (q *clipboardQueue) WriteClipboard() (mime string, content []byte, ok bool) {
-	if q.text == nil {
-		return "", nil, false
-	}
-	content = q.text
-	q.text = nil
-	return q.mime, content, true
-}
-
-// ClipboardRequested reports if any new handler is waiting
-// to read the clipboard.
-func (q *clipboardQueue) ClipboardRequested(state clipboardState) bool {
-	req := len(state.receivers) > 0 && q.requested
-	q.requested = false
-	return req
-}
-
-func (q *clipboardQueue) Push(state clipboardState, e event.Event) (clipboardState, []taggedEvent) {
-	var evts []taggedEvent
-	for _, r := range state.receivers {
-		evts = append(evts, taggedEvent{tag: r, event: e})
-	}
-	state.receivers = nil
-	return state, evts
-}
-
-func (q *clipboardQueue) ProcessWriteClipboard(req clipboard.WriteCmd) {
-	defer req.Data.Close()
-	content, err := io.ReadAll(req.Data)
-	if err != nil {
-		return
-	}
-	q.mime = req.Type
-	q.text = content
-}
-
-func (q *clipboardQueue) ProcessReadClipboard(state clipboardState, tag event.Tag) clipboardState {
-	for _, k := range state.receivers {
-		if k == tag {
-			return state
-		}
-	}
-	n := len(state.receivers)
-	state.receivers = append(state.receivers[:n:n], tag)
-	q.requested = true
-	return state
-}

io/input/clipboard_test.go

@@ -1,125 +0,0 @@
-// SPDX-License-Identifier: Unlicense OR MIT
-
-package input
-
-import (
-	"io"
-	"strings"
-	"testing"
-
-	"gioui.org/io/clipboard"
-	"gioui.org/io/transfer"
-	"gioui.org/op"
-)
-
-func TestClipboardDuplicateEvent(t *testing.T) {
-	ops, r, handlers := new(op.Ops), new(Router), make([]int, 2)
-
-	// Both must receive the event once.
-	r.Source().Execute(clipboard.ReadCmd{Tag: &handlers[0]})
-	r.Source().Execute(clipboard.ReadCmd{Tag: &handlers[1]})
-
-	event := transfer.DataEvent{
-		Type: "application/text",
-		Open: func() io.ReadCloser {
-			return io.NopCloser(strings.NewReader("Test"))
-		},
-	}
-	r.Queue(event)
-	for i := range handlers {
-		f := transfer.TargetFilter{Target: &handlers[i], Type: "application/text"}
-		assertEventTypeSequence(t, events(r, -1, f), transfer.DataEvent{})
-	}
-	assertClipboardReadCmd(t, r, 0)
-
-	r.Source().Execute(clipboard.ReadCmd{Tag: &handlers[0]})
-
-	r.Frame(ops)
-	// No ClipboardEvent sent
-	assertClipboardReadCmd(t, r, 1)
-	for i := range handlers {
-		f := transfer.TargetFilter{Target: &handlers[i]}
-		assertEventTypeSequence(t, events(r, -1, f))
-	}
-}
-
-func TestQueueProcessReadClipboard(t *testing.T) {
-	ops, r, handler := new(op.Ops), new(Router), make([]int, 2)
-
-	// Request read
-	r.Source().Execute(clipboard.ReadCmd{Tag: &handler[0]})
-
-	assertClipboardReadCmd(t, r, 1)
-	ops.Reset()
-
-	for i := 0; i < 3; i++ {
-		// No ReadCmd
-		// One receiver must still wait for response
-
-		r.Frame(ops)
-		assertClipboardReadDuplicated(t, r, 1)
-	}
-
-	// Send the clipboard event
-	event := transfer.DataEvent{
-		Type: "application/text",
-		Open: func() io.ReadCloser {
-			return io.NopCloser(strings.NewReader("Text 2"))
-		},
-	}
-	r.Queue(event)
-	assertEventTypeSequence(t, events(r, -1, transfer.TargetFilter{Target: &handler[0], Type: "application/text"}), transfer.DataEvent{})
-	assertClipboardReadCmd(t, r, 0)
-}
-
-func TestQueueProcessWriteClipboard(t *testing.T) {
-	r := new(Router)
-
-	const mime = "application/text"
-	r.Source().Execute(clipboard.WriteCmd{Type: mime, Data: io.NopCloser(strings.NewReader("Write 1"))})
-
-	assertClipboardWriteCmd(t, r, mime, "Write 1")
-	assertClipboardWriteCmd(t, r, "", "")
-
-	r.Source().Execute(clipboard.WriteCmd{Type: mime, Data: io.NopCloser(strings.NewReader("Write 2"))})
-
-	assertClipboardReadCmd(t, r, 0)
-	assertClipboardWriteCmd(t, r, mime, "Write 2")
-}
-
-func assertClipboardReadCmd(t *testing.T, router *Router, expected int) {
-	t.Helper()
-	if got := len(router.state().receivers); got != expected {
-		t.Errorf("unexpected %d receivers, got %d", expected, got)
-	}
-	if router.ClipboardRequested() != (expected > 0) {
-		t.Error("missing requests")
-	}
-}
-
-func assertClipboardReadDuplicated(t *testing.T, router *Router, expected int) {
-	t.Helper()
-	if len(router.state().receivers) != expected {
-		t.Error("receivers removed")
-	}
-	if router.ClipboardRequested() != false {
-		t.Error("duplicated requests")
-	}
-}
-
-func assertClipboardWriteCmd(t *testing.T, router *Router, mimeExp, expected string) {
-	t.Helper()
-	if (router.cqueue.text != nil) != (expected != "") {
-		t.Error("text not defined")
-	}
-	mime, text, ok := router.cqueue.WriteClipboard()
-	if ok != (expected != "") {
-		t.Error("duplicated requests")
-	}
-	if string(mime) != mimeExp {
-		t.Errorf("got MIME type %s, expected %s", mime, mimeExp)
-	}
-	if string(text) != expected {
-		t.Errorf("got text %s, expected %s", text, expected)
-	}
-}

io/input/doc.go

@@ -1,15 +0,0 @@
-// SPDX-License-Identifier: Unlicense OR MIT
-
-/*
-Package input implements input routing and tracking of interface
-state for a window.
-
-The [Source] is the interface between the window and the widgets
-of a user interface and is exposed by [gioui.org/app.FrameEvent]
-received from windows.
-
-The [Router] is used by [gioui.org/app.Window] to track window state and route
-events from the platform to event handlers. It is otherwise only
-useful for using Gio with external window implementations.
-*/
-package input

io/input/key.go

@@ -1,364 +0,0 @@
-// SPDX-License-Identifier: Unlicense OR MIT
-
-package input
-
-import (
-	"image"
-	"sort"
-
-	"gioui.org/f32"
-	"gioui.org/io/event"
-	"gioui.org/io/key"
-)
-
-// EditorState represents the state of an editor needed by input handlers.
-type EditorState struct {
-	Selection struct {
-		Transform f32.Affine2D
-		key.Range
-		key.Caret
-	}
-	Snippet key.Snippet
-}
-
-type TextInputState uint8
-
-type keyQueue struct {
-	order    []event.Tag
-	dirOrder []dirFocusEntry
-	hint     key.InputHint
-}
-
-// keyState is the input state related to key events.
-type keyState struct {
-	focus   event.Tag
-	state   TextInputState
-	content EditorState
-}
-
-type keyHandler struct {
-	// visible will be true if the InputOp is present
-	// in the current frame.
-	visible bool
-	// reset tracks whether the handler has seen a
-	// focus reset.
-	reset        bool
-	hint         key.InputHint
-	orderPlusOne int
-	dirOrder     int
-	trans        f32.Affine2D
-}
-
-type keyFilter []key.Filter
-
-type dirFocusEntry struct {
-	tag    event.Tag
-	row    int
-	area   int
-	bounds image.Rectangle
-}
-
-const (
-	TextInputKeep TextInputState = iota
-	TextInputClose
-	TextInputOpen
-)
-
-func (k *keyHandler) inputHint(hint key.InputHint) {
-	k.hint = hint
-}
-
-// InputState returns the input state and returns a state
-// reset to [TextInputKeep].
-func (s keyState) InputState() (keyState, TextInputState) {
-	state := s.state
-	s.state = TextInputKeep
-	return s, state
-}
-
-// InputHint returns the input hint from the focused handler and whether it was
-// changed since the last call.
-func (q *keyQueue) InputHint(handlers map[event.Tag]*handler, state keyState) (key.InputHint, bool) {
-	focused, ok := handlers[state.focus]
-	if !ok {
-		return q.hint, false
-	}
-	old := q.hint
-	q.hint = focused.key.hint
-	return q.hint, old != q.hint
-}
-
-func (k *keyHandler) Reset() {
-	k.visible = false
-	k.orderPlusOne = 0
-	k.hint = key.HintAny
-}
-
-func (q *keyQueue) Reset() {
-	q.order = q.order[:0]
-	q.dirOrder = q.dirOrder[:0]
-}
-
-func (k *keyHandler) ResetEvent() (event.Event, bool) {
-	if k.reset {
-		return nil, false
-	}
-	k.reset = true
-	return key.FocusEvent{Focus: false}, true
-}
-
-func (q *keyQueue) Frame(handlers map[event.Tag]*handler, state keyState) keyState {
-	if state.focus != nil {
-		if h, ok := handlers[state.focus]; !ok || !h.filter.focusable || !h.key.visible {
-			// Remove focus from the handler that is no longer focusable.
-			state.focus = nil
-			state.state = TextInputClose
-		}
-	}
-	q.updateFocusLayout(handlers)
-	return state
-}
-
-// updateFocusLayout partitions input handlers handlers into rows
-// for directional focus moves.
-//
-// The approach is greedy: pick the topmost handler and create a row
-// containing it. Then, extend the handler bounds to a horizontal beam
-// and add to the row every handler whose center intersect it. Repeat
-// until no handlers remain.
-func (q *keyQueue) updateFocusLayout(handlers map[event.Tag]*handler) {
-	order := q.dirOrder
-	// Sort by ascending y position.
-	sort.SliceStable(order, func(i, j int) bool {
-		return order[i].bounds.Min.Y < order[j].bounds.Min.Y
-	})
-	row := 0
-	for len(order) > 0 {
-		h := &order[0]
-		h.row = row
-		bottom := h.bounds.Max.Y
-		end := 1
-		for ; end < len(order); end++ {
-			h := &order[end]
-			center := (h.bounds.Min.Y + h.bounds.Max.Y) / 2
-			if center > bottom {
-				break
-			}
-			h.row = row
-		}
-		// Sort row by ascending x position.
-		sort.SliceStable(order[:end], func(i, j int) bool {
-			return order[i].bounds.Min.X < order[j].bounds.Min.X
-		})
-		order = order[end:]
-		row++
-	}
-	for i, o := range q.dirOrder {
-		handlers[o.tag].key.dirOrder = i
-	}
-}
-
-// MoveFocus attempts to move the focus in the direction of dir.
-func (q *keyQueue) MoveFocus(handlers map[event.Tag]*handler, state keyState, dir key.FocusDirection) (keyState, []taggedEvent) {
-	if len(q.dirOrder) == 0 {
-		return state, nil
-	}
-	order := 0
-	if state.focus != nil {
-		order = handlers[state.focus].key.dirOrder
-	}
-	focus := q.dirOrder[order]
-	switch dir {
-	case key.FocusForward, key.FocusBackward:
-		if len(q.order) == 0 {
-			break
-		}
-		order := 0
-		if dir == key.FocusBackward {
-			order = -1
-		}
-		if state.focus != nil {
-			order = handlers[state.focus].key.orderPlusOne - 1
-			if dir == key.FocusForward {
-				order++
-			} else {
-				order--
-			}
-		}
-		order = (order + len(q.order)) % len(q.order)
-		return q.Focus(handlers, state, q.order[order])
-	case key.FocusRight, key.FocusLeft:
-		next := order
-		if state.focus != nil {
-			next = order + 1
-			if dir == key.FocusLeft {
-				next = order - 1
-			}
-		}
-		if 0 <= next && next < len(q.dirOrder) {
-			newFocus := q.dirOrder[next]
-			if newFocus.row == focus.row {
-				return q.Focus(handlers, state, newFocus.tag)
-			}
-		}
-	case key.FocusUp, key.FocusDown:
-		delta := +1
-		if dir == key.FocusUp {
-			delta = -1
-		}
-		nextRow := 0
-		if state.focus != nil {
-			nextRow = focus.row + delta
-		}
-		var closest event.Tag
-		dist := int(1e6)
-		center := (focus.bounds.Min.X + focus.bounds.Max.X) / 2
-	loop:
-		for 0 <= order && order < len(q.dirOrder) {
-			next := q.dirOrder[order]
-			switch next.row {
-			case nextRow:
-				nextCenter := (next.bounds.Min.X + next.bounds.Max.X) / 2
-				d := center - nextCenter
-				if d < 0 {
-					d = -d
-				}
-				if d > dist {
-					break loop
-				}
-				dist = d
-				closest = next.tag
-			case nextRow + delta:
-				break loop
-			}
-			order += delta
-		}
-		if closest != nil {
-			return q.Focus(handlers, state, closest)
-		}
-	}
-	return state, nil
-}
-
-func (q *keyQueue) BoundsFor(k *keyHandler) image.Rectangle {
-	order := k.dirOrder
-	return q.dirOrder[order].bounds
-}
-
-func (q *keyQueue) AreaFor(k *keyHandler) int {
-	order := k.dirOrder
-	return q.dirOrder[order].area
-}
-
-func (k *keyFilter) Matches(focus event.Tag, e key.Event, system bool) bool {
-	for _, f := range *k {
-		if keyFilterMatch(focus, f, e, system) {
-			return true
-		}
-	}
-	return false
-}
-
-func keyFilterMatch(focus event.Tag, f key.Filter, e key.Event, system bool) bool {
-	if f.Focus != nil && f.Focus != focus {
-		return false
-	}
-	if (f.Name != "" || system) && f.Name != e.Name {
-		return false
-	}
-	if e.Modifiers&f.Required != f.Required {
-		return false
-	}
-	if e.Modifiers&^(f.Required|f.Optional) != 0 {
-		return false
-	}
-	return true
-}
-
-func (q *keyQueue) Focus(handlers map[event.Tag]*handler, state keyState, focus event.Tag) (keyState, []taggedEvent) {
-	if focus == state.focus {
-		return state, nil
-	}
-	state.content = EditorState{}
-	var evts []taggedEvent
-	if state.focus != nil {
-		evts = append(evts, taggedEvent{tag: state.focus, event: key.FocusEvent{Focus: false}})
-	}
-	state.focus = focus
-	if state.focus != nil {
-		evts = append(evts, taggedEvent{tag: state.focus, event: key.FocusEvent{Focus: true}})
-	}
-	if state.focus == nil || state.state == TextInputKeep {
-		state.state = TextInputClose
-	}
-	return state, evts
-}
-
-func (s keyState) softKeyboard(show bool) keyState {
-	if show {
-		s.state = TextInputOpen
-	} else {
-		s.state = TextInputClose
-	}
-	return s
-}
-
-func (k *keyFilter) Add(f key.Filter) {
-	for _, f2 := range *k {
-		if f == f2 {
-			return
-		}
-	}
-	*k = append(*k, f)
-}
-
-func (k *keyFilter) Merge(k2 keyFilter) {
-	*k = append(*k, k2...)
-}
-
-func (q *keyQueue) inputOp(tag event.Tag, state *keyHandler, t f32.Affine2D, area int, bounds image.Rectangle) {
-	state.visible = true
-	if state.orderPlusOne == 0 {
-		state.orderPlusOne = len(q.order) + 1
-		q.order = append(q.order, tag)
-		q.dirOrder = append(q.dirOrder, dirFocusEntry{tag: tag, area: area, bounds: bounds})
-	}
-	state.trans = t
-}
-
-func (q *keyQueue) setSelection(state keyState, req key.SelectionCmd) keyState {
-	if req.Tag != state.focus {
-		return state
-	}
-	state.content.Selection.Range = req.Range
-	state.content.Selection.Caret = req.Caret
-	return state
-}
-
-func (q *keyQueue) editorState(handlers map[event.Tag]*handler, state keyState) EditorState {
-	s := state.content
-	if f := state.focus; f != nil {
-		s.Selection.Transform = handlers[f].key.trans
-	}
-	return s
-}
-
-func (q *keyQueue) setSnippet(state keyState, req key.SnippetCmd) keyState {
-	if req.Tag == state.focus {
-		state.content.Snippet = req.Snippet
-	}
-	return state
-}
-
-func (t TextInputState) String() string {
-	switch t {
-	case TextInputKeep:
-		return "Keep"
-	case TextInputClose:
-		return "Close"
-	case TextInputOpen:
-		return "Open"
-	default:
-		panic("unexpected value")
-	}
-}

io/input/key_test.go

@@ -1,331 +0,0 @@
-// SPDX-License-Identifier: Unlicense OR MIT
-
-package input
-
-import (
-	"image"
-	"testing"
-
-	"gioui.org/f32"
-	"gioui.org/io/event"
-	"gioui.org/io/key"
-	"gioui.org/io/pointer"
-	"gioui.org/op"
-	"gioui.org/op/clip"
-)
-
-func TestAllMatchKeyFilter(t *testing.T) {
-	r := new(Router)
-	r.Event(key.Filter{})
-	ke := key.Event{Name: "A"}
-	r.Queue(ke)
-	// Catch-all gets all non-system events.
-	assertEventSequence(t, events(r, -1, key.Filter{}), ke)
-
-	r = new(Router)
-	r.Event(key.Filter{Name: "A"})
-	r.Queue(SystemEvent{ke})
-	if _, handled := r.WakeupTime(); !handled {
-		t.Errorf("system event was unexpectedly ignored")
-	}
-	// Only specific filters match system events.
-	assertEventSequence(t, events(r, -1, key.Filter{Name: "A"}), ke)
-}
-
-func TestInputHint(t *testing.T) {
-	r := new(Router)
-	if hint, changed := r.TextInputHint(); hint != key.HintAny || changed {
-		t.Fatal("unexpected hint")
-	}
-	ops := new(op.Ops)
-	h := new(int)
-	key.InputHintOp{Tag: h, Hint: key.HintEmail}.Add(ops)
-	r.Frame(ops)
-	if hint, changed := r.TextInputHint(); hint != key.HintAny || changed {
-		t.Fatal("unexpected hint")
-	}
-	r.Source().Execute(key.FocusCmd{Tag: h})
-	if hint, changed := r.TextInputHint(); hint != key.HintEmail || !changed {
-		t.Fatal("unexpected hint")
-	}
-}
-
-func TestDeferred(t *testing.T) {
-	r := new(Router)
-	h := new(int)
-	f := []event.Filter{
-		key.FocusFilter{Target: h},
-		key.Filter{Name: "A"},
-	}
-	// Provoke deferring by exhausting events for h.
-	events(r, -1, f...)
-	r.Source().Execute(key.FocusCmd{Tag: h})
-	ke := key.Event{Name: "A"}
-	r.Queue(ke)
-	// All events are deferred at this point.
-	assertEventSequence(t, events(r, -1, f...))
-	r.Frame(new(op.Ops))
-	// But delivered after a frame.
-	assertEventSequence(t, events(r, -1, f...), key.FocusEvent{Focus: true}, ke)
-}
-
-func TestInputWakeup(t *testing.T) {
-	handler := new(int)
-	var ops op.Ops
-	// InputOps shouldn't trigger redraws.
-	event.Op(&ops, handler)
-
-	var r Router
-	// Reset events shouldn't either.
-	evts := events(&r, -1, key.FocusFilter{Target: new(int)}, key.Filter{Name: "A"})
-	assertEventSequence(t, evts, key.FocusEvent{Focus: false})
-	r.Frame(&ops)
-	if _, wake := r.WakeupTime(); wake {
-		t.Errorf("InputOp or the resetting FocusEvent triggered a wakeup")
-	}
-	// And neither does events that don't match anything.
-	r.Queue(key.SnippetEvent{})
-	if _, handled := r.WakeupTime(); handled {
-		t.Errorf("a not-matching event triggered a wakeup")
-	}
-	// However, events that does match should trigger wakeup.
-	r.Queue(key.Event{Name: "A"})
-	if _, handled := r.WakeupTime(); !handled {
-		t.Errorf("a key.Event didn't trigger redraw")
-	}
-}
-
-func TestKeyMultiples(t *testing.T) {
-	handlers := make([]int, 3)
-	r := new(Router)
-	r.Source().Execute(key.SoftKeyboardCmd{Show: true})
-	for i := range handlers {
-		assertEventSequence(t, events(r, 1, key.FocusFilter{Target: &handlers[i]}), key.FocusEvent{Focus: false})
-	}
-	r.Source().Execute(key.FocusCmd{Tag: &handlers[2]})
-	assertEventSequence(t, events(r, -1, key.FocusFilter{Target: &handlers[2]}), key.FocusEvent{Focus: true})
-	assertFocus(t, r, &handlers[2])
-
-	assertKeyboard(t, r, TextInputOpen)
-}
-
-func TestKeySoftKeyboardNoFocus(t *testing.T) {
-	r := new(Router)
-
-	// It's possible to open the keyboard
-	// without any active focus:
-	r.Source().Execute(key.SoftKeyboardCmd{Show: true})
-
-	assertFocus(t, r, nil)
-	assertKeyboard(t, r, TextInputOpen)
-}
-
-func TestKeyRemoveFocus(t *testing.T) {
-	handlers := make([]int, 2)
-	r := new(Router)
-
-	filters := func(h event.Tag) []event.Filter {
-		return []event.Filter{
-			key.FocusFilter{Target: h},
-			key.Filter{Focus: h, Name: key.NameTab, Required: key.ModShortcut},
-		}
-	}
-	var all []event.Filter
-	for i := range handlers {
-		all = append(all, filters(&handlers[i])...)
-	}
-	assertEventSequence(t, events(r, len(handlers), all...), key.FocusEvent{}, key.FocusEvent{})
-	r.Source().Execute(key.FocusCmd{Tag: &handlers[0]})
-	r.Source().Execute(key.SoftKeyboardCmd{Show: true})
-
-	evt := key.Event{Name: key.NameTab, Modifiers: key.ModShortcut, State: key.Press}
-	r.Queue(evt)
-
-	assertEventSequence(t, events(r, 2, filters(&handlers[0])...), key.FocusEvent{Focus: true}, evt)
-	assertFocus(t, r, &handlers[0])
-	assertKeyboard(t, r, TextInputOpen)
-
-	// Frame removes focus from tags that don't filter for focus events nor mentioned in an InputOp.
-	r.Source().Execute(key.FocusCmd{Tag: new(int)})
-	r.Frame(new(op.Ops))
-
-	assertEventSequence(t, events(r, -1, filters(&handlers[1])...))
-	assertFocus(t, r, nil)
-	assertKeyboard(t, r, TextInputClose)
-
-	// Set focus to InputOp which already
-	// exists in the previous frame:
-	r.Source().Execute(key.FocusCmd{Tag: &handlers[0]})
-	assertFocus(t, r, &handlers[0])
-}
-
-func TestKeyFocusedInvisible(t *testing.T) {
-	handlers := make([]int, 2)
-	ops := new(op.Ops)
-	r := new(Router)
-
-	for i := range handlers {
-		assertEventSequence(t, events(r, 1, key.FocusFilter{Target: &handlers[i]}), key.FocusEvent{Focus: false})
-	}
-
-	// Set new InputOp with focus:
-	r.Source().Execute(key.FocusCmd{Tag: &handlers[0]})
-	r.Source().Execute(key.SoftKeyboardCmd{Show: true})
-
-	assertEventSequence(t, events(r, 1, key.FocusFilter{Target: &handlers[0]}), key.FocusEvent{Focus: true})
-	assertFocus(t, r, &handlers[0])
-	assertKeyboard(t, r, TextInputOpen)
-
-	// Frame will clear the focus because the handler is not visible.
-	r.Frame(ops)
-
-	for i := range handlers {
-		assertEventSequence(t, events(r, -1, key.FocusFilter{Target: &handlers[i]}))
-	}
-	assertFocus(t, r, nil)
-	assertKeyboard(t, r, TextInputClose)
-
-	r.Frame(ops)
-	r.Frame(ops)
-
-	ops.Reset()
-
-	// Respawn the first element:
-	// It must receive one `Event{Focus: false}`.
-	event.Op(ops, &handlers[0])
-
-	assertEventSequence(t, events(r, -1, key.FocusFilter{Target: &handlers[0]}), key.FocusEvent{Focus: false})
-}
-
-func TestNoOps(t *testing.T) {
-	r := new(Router)
-	r.Frame(nil)
-}
-
-func TestDirectionalFocus(t *testing.T) {
-	ops := new(op.Ops)
-	r := new(Router)
-	handlers := []image.Rectangle{
-		image.Rect(10, 10, 50, 50),
-		image.Rect(50, 20, 100, 80),
-		image.Rect(20, 26, 60, 80),
-		image.Rect(10, 60, 50, 100),
-	}
-
-	for i, bounds := range handlers {
-		cl := clip.Rect(bounds).Push(ops)
-		event.Op(ops, &handlers[i])
-		cl.Pop()
-		events(r, -1, key.FocusFilter{Target: &handlers[i]})
-	}
-	r.Frame(ops)
-
-	r.MoveFocus(key.FocusLeft)
-	assertFocus(t, r, &handlers[0])
-	r.MoveFocus(key.FocusLeft)
-	assertFocus(t, r, &handlers[0])
-	r.MoveFocus(key.FocusRight)
-	assertFocus(t, r, &handlers[1])
-	r.MoveFocus(key.FocusRight)
-	assertFocus(t, r, &handlers[1])
-	r.MoveFocus(key.FocusDown)
-	assertFocus(t, r, &handlers[2])
-	r.MoveFocus(key.FocusDown)
-	assertFocus(t, r, &handlers[2])
-	r.MoveFocus(key.FocusLeft)
-	assertFocus(t, r, &handlers[3])
-	r.MoveFocus(key.FocusUp)
-	assertFocus(t, r, &handlers[0])
-
-	r.MoveFocus(key.FocusForward)
-	assertFocus(t, r, &handlers[1])
-	r.MoveFocus(key.FocusBackward)
-	assertFocus(t, r, &handlers[0])
-}
-
-func TestFocusScroll(t *testing.T) {
-	ops := new(op.Ops)
-	r := new(Router)
-	h := new(int)
-
-	filters := []event.Filter{
-		key.FocusFilter{Target: h},
-		pointer.Filter{
-			Target:       h,
-			Kinds:        pointer.Scroll,
-			ScrollBounds: image.Rect(-100, -100, 100, 100),
-		},
-	}
-	events(r, -1, filters...)
-	parent := clip.Rect(image.Rect(1, 1, 14, 39)).Push(ops)
-	cl := clip.Rect(image.Rect(10, -20, 20, 30)).Push(ops)
-	event.Op(ops, h)
-	// Test that h is scrolled even if behind another handler.
-	event.Op(ops, new(int))
-	cl.Pop()
-	parent.Pop()
-	r.Frame(ops)
-
-	r.MoveFocus(key.FocusLeft)
-	r.RevealFocus(image.Rect(0, 0, 15, 40))
-	evts := events(r, -1, filters...)
-	assertScrollEvent(t, evts[len(evts)-1], f32.Pt(6, -9))
-}
-
-func TestFocusClick(t *testing.T) {
-	ops := new(op.Ops)
-	r := new(Router)
-	h := new(int)
-
-	filters := []event.Filter{
-		key.FocusFilter{Target: h},
-		pointer.Filter{
-			Target: h,
-			Kinds:  pointer.Press | pointer.Release | pointer.Cancel,
-		},
-	}
-	assertEventPointerTypeSequence(t, events(r, -1, filters...), pointer.Cancel)
-	cl := clip.Rect(image.Rect(0, 0, 10, 10)).Push(ops)
-	event.Op(ops, h)
-	cl.Pop()
-	r.Frame(ops)
-
-	r.MoveFocus(key.FocusLeft)
-	r.ClickFocus()
-
-	assertEventPointerTypeSequence(t, events(r, -1, filters...), pointer.Press, pointer.Release)
-}
-
-func TestNoFocus(t *testing.T) {
-	r := new(Router)
-	r.MoveFocus(key.FocusForward)
-}
-
-func TestKeyRouting(t *testing.T) {
-	r := new(Router)
-	h := new(int)
-	A, B := key.Event{Name: "A"}, key.Event{Name: "B"}
-	// Register filters.
-	events(r, -1, key.Filter{Name: "A"}, key.Filter{Name: "B"})
-	r.Frame(new(op.Ops))
-	r.Queue(A, B)
-	// The handler is not focused, so only B is delivered.
-	assertEventSequence(t, events(r, -1, key.Filter{Focus: h, Name: "A"}, key.Filter{Name: "B"}), B)
-	r.Source().Execute(key.FocusCmd{Tag: h})
-	// A is delivered to the focused handler.
-	assertEventSequence(t, events(r, -1, key.Filter{Focus: h, Name: "A"}, key.Filter{Name: "B"}), A)
-}
-
-func assertFocus(t *testing.T, router *Router, expected event.Tag) {
-	t.Helper()
-	if !router.Source().Focused(expected) {
-		t.Errorf("expected %v to be focused", expected)
-	}
-}
-
-func assertKeyboard(t *testing.T, router *Router, expected TextInputState) {
-	t.Helper()
-	if got := router.state().state; got != expected {
-		t.Errorf("expected %v keyboard, got %v", expected, got)
-	}
-}

io/input/router.go

@@ -1,882 +0,0 @@
-// SPDX-License-Identifier: Unlicense OR MIT
-
-package input
-
-import (
-	"image"
-	"io"
-	"strings"
-	"time"
-
-	"gioui.org/f32"
-	f32internal "gioui.org/internal/f32"
-	"gioui.org/internal/ops"
-	"gioui.org/io/clipboard"
-	"gioui.org/io/event"
-	"gioui.org/io/key"
-	"gioui.org/io/pointer"
-	"gioui.org/io/semantic"
-	"gioui.org/io/system"
-	"gioui.org/io/transfer"
-	"gioui.org/op"
-)
-
-// Router tracks the [io/event.Tag] identifiers of user interface widgets
-// and routes events to them. [Source] is its interface exposed to widgets.
-type Router struct {
-	savedTrans []f32.Affine2D
-	transStack []f32.Affine2D
-	handlers   map[event.Tag]*handler
-	pointer    struct {
-		queue     pointerQueue
-		collector pointerCollector
-	}
-	key struct {
-		queue keyQueue
-		// The following fields have the same purpose as the fields in
-		// type handler, but for key.Events.
-		filter          keyFilter
-		nextFilter      keyFilter
-		processedFilter keyFilter
-		scratchFilter   keyFilter
-	}
-	cqueue clipboardQueue
-	// states is the list of pending state changes resulting from
-	// incoming events. The first element, if present, contains the state
-	// and events for the current frame.
-	changes []stateChange
-	reader  ops.Reader
-	// InvalidateCmd summary.
-	wakeup     bool
-	wakeupTime time.Time
-	// Changes queued for next call to Frame.
-	commands []Command
-	// transfers is the pending transfer.DataEvent.Open functions.
-	transfers []io.ReadCloser
-	// deferring is set if command execution and event delivery is deferred
-	// to the next frame.
-	deferring bool
-	// scratchFilters is for garbage-free construction of ephemeral filters.
-	scratchFilters []taggedFilter
-}
-
-// Source implements the interface between a Router and user interface widgets.
-// The value Source is disabled.
-type Source struct {
-	r *Router
-}
-
-// Command represents a request such as moving the focus, or initiating a clipboard read.
-// Commands are queued by calling [Source.Queue].
-type Command interface {
-	ImplementsCommand()
-}
-
-// SemanticNode represents a node in the tree describing the components
-// contained in a frame.
-type SemanticNode struct {
-	ID       SemanticID
-	ParentID SemanticID
-	Children []SemanticNode
-	Desc     SemanticDesc
-
-	areaIdx int
-}
-
-// SemanticDesc provides a semantic description of a UI component.
-type SemanticDesc struct {
-	Class       semantic.ClassOp
-	Description string
-	Label       string
-	Selected    bool
-	Disabled    bool
-	Gestures    SemanticGestures
-	Bounds      image.Rectangle
-}
-
-// SemanticGestures is a bit-set of supported gestures.
-type SemanticGestures int
-
-const (
-	ClickGesture SemanticGestures = 1 << iota
-	ScrollGesture
-)
-
-// SemanticID uniquely identifies a SemanticDescription.
-//
-// By convention, the zero value denotes the non-existent ID.
-type SemanticID uint
-
-// SystemEvent is a marker for events that have platform specific
-// side-effects. SystemEvents are never matched by catch-all filters.
-type SystemEvent struct {
-	Event event.Event
-}
-
-// handler contains the per-handler state tracked by a [Router].
-type handler struct {
-	// active tracks whether the handler was active in the current
-	// frame. Router deletes state belonging to inactive handlers during Frame.
-	active  bool
-	pointer pointerHandler
-	key     keyHandler
-	// filter the handler has asked for through event handling
-	// in the previous frame. It is used for routing events in the
-	// current frame.
-	filter filter
-	// prevFilter is the filter being built in the current frame.
-	nextFilter filter
-	// processedFilter is the filters that have exhausted available events.
-	processedFilter filter
-}
-
-// filter is the union of a set of [io/event.Filters].
-type filter struct {
-	pointer   pointerFilter
-	focusable bool
-}
-
-// taggedFilter is a filter for a particular tag.
-type taggedFilter struct {
-	tag    event.Tag
-	filter filter
-}
-
-// stateChange represents the new state and outgoing events
-// resulting from an incoming event.
-type stateChange struct {
-	// event, if set, is the trigger for the change.
-	event  event.Event
-	state  inputState
-	events []taggedEvent
-}
-
-// inputState represent a immutable snapshot of the state required
-// to route events.
-type inputState struct {
-	clipboardState
-	keyState
-	pointerState
-}
-
-// taggedEvent represents an event and its target handler.
-type taggedEvent struct {
-	event event.Event
-	tag   event.Tag
-}
-
-// Source returns a Source backed by this Router.
-func (q *Router) Source() Source {
-	return Source{r: q}
-}
-
-// Execute a command.
-func (s Source) Execute(c Command) {
-	if !s.Enabled() {
-		return
-	}
-	s.r.execute(c)
-}
-
-// Enabled reports whether the source is enabled. Only enabled
-// Sources deliver events and respond to commands.
-func (s Source) Enabled() bool {
-	return s.r != nil
-}
-
-// Focused reports whether tag is focused, according to the most recent
-// [key.FocusEvent] delivered.
-func (s Source) Focused(tag event.Tag) bool {
-	if !s.Enabled() {
-		return false
-	}
-	return s.r.state().keyState.focus == tag
-}
-
-// Event returns the next event that matches at least one of filters.
-func (s Source) Event(filters ...event.Filter) (event.Event, bool) {
-	if !s.Enabled() {
-		return nil, false
-	}
-	return s.r.Event(filters...)
-}
-
-func (q *Router) Event(filters ...event.Filter) (event.Event, bool) {
-	// Merge filters into scratch filters.
-	q.scratchFilters = q.scratchFilters[:0]
-	q.key.scratchFilter = q.key.scratchFilter[:0]
-	for _, f := range filters {
-		var t event.Tag
-		switch f := f.(type) {
-		case key.Filter:
-			q.key.scratchFilter = append(q.key.scratchFilter, f)
-			continue
-		case transfer.SourceFilter:
-			t = f.Target
-		case transfer.TargetFilter:
-			t = f.Target
-		case key.FocusFilter:
-			t = f.Target
-		case pointer.Filter:
-			t = f.Target
-		}
-		if t == nil {
-			continue
-		}
-		var filter *filter
-		for i := range q.scratchFilters {
-			s := &q.scratchFilters[i]
-			if s.tag == t {
-				filter = &s.filter
-				break
-			}
-		}
-		if filter == nil {
-			n := len(q.scratchFilters)
-			if n < cap(q.scratchFilters) {
-				// Re-use previously allocated filter.
-				q.scratchFilters = q.scratchFilters[:n+1]
-				tf := &q.scratchFilters[n]
-				tf.tag = t
-				filter = &tf.filter
-				filter.Reset()
-			} else {
-				q.scratchFilters = append(q.scratchFilters, taggedFilter{tag: t})
-				filter = &q.scratchFilters[n].filter
-			}
-		}
-		filter.Add(f)
-	}
-	for _, tf := range q.scratchFilters {
-		h := q.stateFor(tf.tag)
-		h.filter.Merge(tf.filter)
-		h.nextFilter.Merge(tf.filter)
-	}
-	q.key.filter = append(q.key.filter, q.key.scratchFilter...)
-	q.key.nextFilter = append(q.key.nextFilter, q.key.scratchFilter...)
-	// Deliver reset event, if any.
-	for _, f := range filters {
-		switch f := f.(type) {
-		case key.FocusFilter:
-			if f.Target == nil {
-				break
-			}
-			h := q.stateFor(f.Target)
-			if reset, ok := h.key.ResetEvent(); ok {
-				return reset, true
-			}
-		case pointer.Filter:
-			if f.Target == nil {
-				break
-			}
-			h := q.stateFor(f.Target)
-			if reset, ok := h.pointer.ResetEvent(); ok && h.filter.pointer.Matches(reset) {
-				return reset, true
-			}
-		}
-	}
-	if !q.deferring {
-		for i := range q.changes {
-			change := &q.changes[i]
-			for j, evt := range change.events {
-				match := false
-				switch e := evt.event.(type) {
-				case key.Event:
-					match = q.key.scratchFilter.Matches(change.state.keyState.focus, e, false)
-				default:
-					for _, tf := range q.scratchFilters {
-						if evt.tag == tf.tag && tf.filter.Matches(evt.event) {
-							match = true
-							break
-						}
-					}
-				}
-				if match {
-					change.events = append(change.events[:j], change.events[j+1:]...)
-					// Fast forward state to last matched.
-					q.collapseState(i)
-					return evt.event, true
-				}
-			}
-		}
-	}
-	for _, tf := range q.scratchFilters {
-		h := q.stateFor(tf.tag)
-		h.processedFilter.Merge(tf.filter)
-	}
-	q.key.processedFilter = append(q.key.processedFilter, q.key.scratchFilter...)
-	return nil, false
-}
-
-// collapseState in the interval [1;idx] into q.changes[0].
-func (q *Router) collapseState(idx int) {
-	if idx == 0 {
-		return
-	}
-	first := &q.changes[0]
-	first.state = q.changes[idx].state
-	for i := 1; i <= idx; i++ {
-		first.events = append(first.events, q.changes[i].events...)
-	}
-	q.changes = append(q.changes[:1], q.changes[idx+1:]...)
-}
-
-// Frame replaces the declared handlers from the supplied
-// operation list. The text input state, wakeup time and whether
-// there are active profile handlers is also saved.
-func (q *Router) Frame(frame *op.Ops) {
-	var remaining []event.Event
-	if n := len(q.changes); n > 0 {
-		if q.deferring {
-			// Collect events for replay.
-			for _, ch := range q.changes[1:] {
-				remaining = append(remaining, ch.event)
-			}
-			q.changes = append(q.changes[:0], stateChange{state: q.changes[0].state})
-		} else {
-			// Collapse state.
-			state := q.changes[n-1].state
-			q.changes = append(q.changes[:0], stateChange{state: state})
-		}
-	}
-	for _, rc := range q.transfers {
-		if rc != nil {
-			rc.Close()
-		}
-	}
-	q.transfers = nil
-	q.deferring = false
-	for _, h := range q.handlers {
-		h.filter, h.nextFilter = h.nextFilter, h.filter
-		h.nextFilter.Reset()
-		h.processedFilter.Reset()
-		h.pointer.Reset()
-		h.key.Reset()
-	}
-	q.key.filter, q.key.nextFilter = q.key.nextFilter, q.key.filter
-	q.key.nextFilter = q.key.nextFilter[:0]
-	var ops *ops.Ops
-	if frame != nil {
-		ops = &frame.Internal
-	}
-	q.reader.Reset(ops)
-	q.collect()
-	for k, h := range q.handlers {
-		if !h.active {
-			delete(q.handlers, k)
-		} else {
-			h.active = false
-		}
-	}
-	q.executeCommands()
-	q.Queue(remaining...)
-	st := q.lastState()
-	pst, evts := q.pointer.queue.Frame(q.handlers, st.pointerState)
-	st.pointerState = pst
-	st.keyState = q.key.queue.Frame(q.handlers, q.lastState().keyState)
-	q.changeState(nil, st, evts)
-
-	// Collapse state and events.
-	q.collapseState(len(q.changes) - 1)
-}
-
-// Queue events to be routed.
-func (q *Router) Queue(events ...event.Event) {
-	for _, e := range events {
-		se, system := e.(SystemEvent)
-		if system {
-			e = se.Event
-		}
-		q.processEvent(e, system)
-	}
-}
-
-func (f *filter) Add(flt event.Filter) {
-	switch flt := flt.(type) {
-	case key.FocusFilter:
-		f.focusable = true
-	case pointer.Filter:
-		f.pointer.Add(flt)
-	case transfer.SourceFilter, transfer.TargetFilter:
-		f.pointer.Add(flt)
-	}
-}
-
-// Merge f2 into f.
-func (f *filter) Merge(f2 filter) {
-	f.focusable = f.focusable || f2.focusable
-	f.pointer.Merge(f2.pointer)
-}
-
-func (f *filter) Matches(e event.Event) bool {
-	switch e.(type) {
-	case key.FocusEvent, key.SnippetEvent, key.EditEvent, key.SelectionEvent:
-		return f.focusable
-	default:
-		return f.pointer.Matches(e)
-	}
-}
-
-func (f *filter) Reset() {
-	*f = filter{
-		pointer: pointerFilter{
-			sourceMimes: f.pointer.sourceMimes[:0],
-			targetMimes: f.pointer.targetMimes[:0],
-		},
-	}
-}
-
-func (q *Router) processEvent(e event.Event, system bool) {
-	state := q.lastState()
-	switch e := e.(type) {
-	case pointer.Event:
-		pstate, evts := q.pointer.queue.Push(q.handlers, state.pointerState, e)
-		state.pointerState = pstate
-		q.changeState(e, state, evts)
-	case key.Event:
-		var evts []taggedEvent
-		if q.key.filter.Matches(state.keyState.focus, e, system) {
-			evts = append(evts, taggedEvent{event: e})
-		}
-		q.changeState(e, state, evts)
-	case key.SnippetEvent:
-		// Expand existing, overlapping snippet.
-		if r := state.content.Snippet.Range; rangeOverlaps(r, key.Range(e)) {
-			if e.Start > r.Start {
-				e.Start = r.Start
-			}
-			if e.End < r.End {
-				e.End = r.End
-			}
-		}
-		var evts []taggedEvent
-		if f := state.focus; f != nil {
-			evts = append(evts, taggedEvent{tag: f, event: e})
-		}
-		q.changeState(e, state, evts)
-	case key.EditEvent, key.FocusEvent, key.SelectionEvent:
-		var evts []taggedEvent
-		if f := state.focus; f != nil {
-			evts = append(evts, taggedEvent{tag: f, event: e})
-		}
-		q.changeState(e, state, evts)
-	case transfer.DataEvent:
-		cstate, evts := q.cqueue.Push(state.clipboardState, e)
-		state.clipboardState = cstate
-		q.changeState(e, state, evts)
-	default:
-		panic("unknown event type")
-	}
-}
-
-func (q *Router) execute(c Command) {
-	// The command can be executed immediately if event delivery is not frozen, and
-	// no event receiver has completed their event handling.
-	if !q.deferring {
-		ch := q.executeCommand(c)
-		immediate := true
-		for _, e := range ch.events {
-			h, ok := q.handlers[e.tag]
-			immediate = immediate && (!ok || !h.processedFilter.Matches(e.event))
-		}
-		if immediate {
-			// Hold on to the remaining events for state replay.
-			var evts []event.Event
-			for _, ch := range q.changes {
-				if ch.event != nil {
-					evts = append(evts, ch.event)
-				}
-			}
-			if len(q.changes) > 1 {
-				q.changes = q.changes[:1]
-			}
-			q.changeState(nil, ch.state, ch.events)
-			q.Queue(evts...)
-			return
-		}
-	}
-	q.deferring = true
-	q.commands = append(q.commands, c)
-}
-
-func (q *Router) state() inputState {
-	if len(q.changes) > 0 {
-		return q.changes[0].state
-	}
-	return inputState{}
-}
-
-func (q *Router) lastState() inputState {
-	if n := len(q.changes); n > 0 {
-		return q.changes[n-1].state
-	}
-	return inputState{}
-}
-
-func (q *Router) executeCommands() {
-	for _, c := range q.commands {
-		ch := q.executeCommand(c)
-		q.changeState(nil, ch.state, ch.events)
-	}
-	q.commands = nil
-}
-
-// executeCommand the command and return the resulting state change along with the
-// tag the state change depended on, if any.
-func (q *Router) executeCommand(c Command) stateChange {
-	state := q.state()
-	var evts []taggedEvent
-	switch req := c.(type) {
-	case key.SelectionCmd:
-		state.keyState = q.key.queue.setSelection(state.keyState, req)
-	case key.FocusCmd:
-		state.keyState, evts = q.key.queue.Focus(q.handlers, state.keyState, req.Tag)
-	case key.SoftKeyboardCmd:
-		state.keyState = state.keyState.softKeyboard(req.Show)
-	case key.SnippetCmd:
-		state.keyState = q.key.queue.setSnippet(state.keyState, req)
-	case transfer.OfferCmd:
-		state.pointerState, evts = q.pointer.queue.offerData(q.handlers, state.pointerState, req)
-	case clipboard.WriteCmd:
-		q.cqueue.ProcessWriteClipboard(req)
-	case clipboard.ReadCmd:
-		state.clipboardState = q.cqueue.ProcessReadClipboard(state.clipboardState, req.Tag)
-	case pointer.GrabCmd:
-		state.pointerState, evts = q.pointer.queue.grab(state.pointerState, req)
-	case op.InvalidateCmd:
-		if !q.wakeup || req.At.Before(q.wakeupTime) {
-			q.wakeup = true
-			q.wakeupTime = req.At
-		}
-	}
-	return stateChange{state: state, events: evts}
-}
-
-func (q *Router) changeState(e event.Event, state inputState, evts []taggedEvent) {
-	// Wrap pointer.DataEvent.Open functions to detect them not being called.
-	for i := range evts {
-		e := &evts[i]
-		if de, ok := e.event.(transfer.DataEvent); ok {
-			transferIdx := len(q.transfers)
-			data := de.Open()
-			q.transfers = append(q.transfers, data)
-			de.Open = func() io.ReadCloser {
-				q.transfers[transferIdx] = nil
-				return data
-			}
-			e.event = de
-		}
-	}
-	// Initialize the first change to contain the current state
-	// and events that are bound for the current frame.
-	if len(q.changes) == 0 {
-		q.changes = append(q.changes, stateChange{})
-	}
-	if e != nil && len(evts) > 0 {
-		// An event triggered events bound for user receivers. Add a state change to be
-		// able to redo the change in case of a command execution.
-		q.changes = append(q.changes, stateChange{event: e, state: state, events: evts})
-	} else {
-		// Otherwise, merge with previous change.
-		prev := &q.changes[len(q.changes)-1]
-		prev.state = state
-		prev.events = append(prev.events, evts...)
-	}
-}
-
-func rangeOverlaps(r1, r2 key.Range) bool {
-	r1 = rangeNorm(r1)
-	r2 = rangeNorm(r2)
-	return r1.Start <= r2.Start && r2.Start < r1.End ||
-		r1.Start <= r2.End && r2.End < r1.End
-}
-
-func rangeNorm(r key.Range) key.Range {
-	if r.End < r.Start {
-		r.End, r.Start = r.Start, r.End
-	}
-	return r
-}
-
-func (q *Router) MoveFocus(dir key.FocusDirection) {
-	state := q.lastState()
-	kstate, evts := q.key.queue.MoveFocus(q.handlers, state.keyState, dir)
-	state.keyState = kstate
-	q.changeState(nil, state, evts)
-}
-
-// RevealFocus scrolls the current focus (if any) into viewport
-// if there are scrollable parent handlers.
-func (q *Router) RevealFocus(viewport image.Rectangle) {
-	state := q.lastState()
-	focus := state.focus
-	if focus == nil {
-		return
-	}
-	kh := &q.handlers[focus].key
-	bounds := q.key.queue.BoundsFor(kh)
-	area := q.key.queue.AreaFor(kh)
-	viewport = q.pointer.queue.ClipFor(area, viewport)
-
-	topleft := bounds.Min.Sub(viewport.Min)
-	topleft = max(topleft, bounds.Max.Sub(viewport.Max))
-	topleft = min(image.Pt(0, 0), topleft)
-	bottomright := bounds.Max.Sub(viewport.Max)
-	bottomright = min(bottomright, bounds.Min.Sub(viewport.Min))
-	bottomright = max(image.Pt(0, 0), bottomright)
-	s := topleft
-	if s.X == 0 {
-		s.X = bottomright.X
-	}
-	if s.Y == 0 {
-		s.Y = bottomright.Y
-	}
-	q.ScrollFocus(s)
-}
-
-// ScrollFocus scrolls the focused widget, if any, by dist.
-func (q *Router) ScrollFocus(dist image.Point) {
-	state := q.lastState()
-	focus := state.focus
-	if focus == nil {
-		return
-	}
-	kh := &q.handlers[focus].key
-	area := q.key.queue.AreaFor(kh)
-	q.changeState(nil, q.lastState(), q.pointer.queue.Deliver(q.handlers, area, pointer.Event{
-		Kind:   pointer.Scroll,
-		Source: pointer.Touch,
-		Scroll: f32internal.FPt(dist),
-	}))
-}
-
-func max(p1, p2 image.Point) image.Point {
-	m := p1
-	if p2.X > m.X {
-		m.X = p2.X
-	}
-	if p2.Y > m.Y {
-		m.Y = p2.Y
-	}
-	return m
-}
-
-func min(p1, p2 image.Point) image.Point {
-	m := p1
-	if p2.X < m.X {
-		m.X = p2.X
-	}
-	if p2.Y < m.Y {
-		m.Y = p2.Y
-	}
-	return m
-}
-
-func (q *Router) ActionAt(p f32.Point) (system.Action, bool) {
-	return q.pointer.queue.ActionAt(p)
-}
-
-func (q *Router) ClickFocus() {
-	focus := q.lastState().focus
-	if focus == nil {
-		return
-	}
-	kh := &q.handlers[focus].key
-	bounds := q.key.queue.BoundsFor(kh)
-	center := bounds.Max.Add(bounds.Min).Div(2)
-	e := pointer.Event{
-		Position: f32.Pt(float32(center.X), float32(center.Y)),
-		Source:   pointer.Touch,
-	}
-	area := q.key.queue.AreaFor(kh)
-	e.Kind = pointer.Press
-	state := q.lastState()
-	q.changeState(nil, state, q.pointer.queue.Deliver(q.handlers, area, e))
-	e.Kind = pointer.Release
-	q.changeState(nil, state, q.pointer.queue.Deliver(q.handlers, area, e))
-}
-
-// TextInputState returns the input state from the most recent
-// call to Frame.
-func (q *Router) TextInputState() TextInputState {
-	state := q.state()
-	kstate, s := state.InputState()
-	state.keyState = kstate
-	q.changeState(nil, state, nil)
-	return s
-}
-
-// TextInputHint returns the input mode from the most recent key.InputOp.
-func (q *Router) TextInputHint() (key.InputHint, bool) {
-	return q.key.queue.InputHint(q.handlers, q.state().keyState)
-}
-
-// WriteClipboard returns the most recent content to be copied
-// to the clipboard, if any.
-func (q *Router) WriteClipboard() (mime string, content []byte, ok bool) {
-	return q.cqueue.WriteClipboard()
-}
-
-// ClipboardRequested reports if any new handler is waiting
-// to read the clipboard.
-func (q *Router) ClipboardRequested() bool {
-	return q.cqueue.ClipboardRequested(q.lastState().clipboardState)
-}
-
-// Cursor returns the last cursor set.
-func (q *Router) Cursor() pointer.Cursor {
-	return q.state().cursor
-}
-
-// SemanticAt returns the first semantic description under pos, if any.
-func (q *Router) SemanticAt(pos f32.Point) (SemanticID, bool) {
-	return q.pointer.queue.SemanticAt(pos)
-}
-
-// AppendSemantics appends the semantic tree to nodes, and returns the result.
-// The root node is the first added.
-func (q *Router) AppendSemantics(nodes []SemanticNode) []SemanticNode {
-	q.pointer.collector.q = &q.pointer.queue
-	q.pointer.collector.ensureRoot()
-	return q.pointer.queue.AppendSemantics(nodes)
-}
-
-// EditorState returns the editor state for the focused handler, or the
-// zero value if there is none.
-func (q *Router) EditorState() EditorState {
-	return q.key.queue.editorState(q.handlers, q.state().keyState)
-}
-
-func (q *Router) stateFor(tag event.Tag) *handler {
-	if tag == nil {
-		panic("internal error: nil tag")
-	}
-	s, ok := q.handlers[tag]
-	if !ok {
-		s = new(handler)
-		if q.handlers == nil {
-			q.handlers = make(map[event.Tag]*handler)
-		}
-		q.handlers[tag] = s
-	}
-	s.active = true
-	return s
-}
-
-func (q *Router) collect() {
-	q.transStack = q.transStack[:0]
-	pc := &q.pointer.collector
-	pc.q = &q.pointer.queue
-	pc.Reset()
-	kq := &q.key.queue
-	q.key.queue.Reset()
-	var t f32.Affine2D
-	for encOp, ok := q.reader.Decode(); ok; encOp, ok = q.reader.Decode() {
-		switch ops.OpType(encOp.Data[0]) {
-		case ops.TypeSave:
-			id := ops.DecodeSave(encOp.Data)
-			if extra := id - len(q.savedTrans) + 1; extra > 0 {
-				q.savedTrans = append(q.savedTrans, make([]f32.Affine2D, extra)...)
-			}
-			q.savedTrans[id] = t
-		case ops.TypeLoad:
-			id := ops.DecodeLoad(encOp.Data)
-			t = q.savedTrans[id]
-			pc.resetState()
-			pc.setTrans(t)
-
-		case ops.TypeClip:
-			var op ops.ClipOp
-			op.Decode(encOp.Data)
-			pc.clip(op)
-		case ops.TypePopClip:
-			pc.popArea()
-		case ops.TypeTransform:
-			t2, push := ops.DecodeTransform(encOp.Data)
-			if push {
-				q.transStack = append(q.transStack, t)
-			}
-			t = t.Mul(t2)
-			pc.setTrans(t)
-		case ops.TypePopTransform:
-			n := len(q.transStack)
-			t = q.transStack[n-1]
-			q.transStack = q.transStack[:n-1]
-			pc.setTrans(t)
-
-		case ops.TypeInput:
-			tag := encOp.Refs[0].(event.Tag)
-			s := q.stateFor(tag)
-			pc.inputOp(tag, &s.pointer)
-			a := pc.currentArea()
-			b := pc.currentAreaBounds()
-			if s.filter.focusable {
-				kq.inputOp(tag, &s.key, t, a, b)
-			}
-
-		// Pointer ops.
-		case ops.TypePass:
-			pc.pass()
-		case ops.TypePopPass:
-			pc.popPass()
-		case ops.TypeCursor:
-			name := pointer.Cursor(encOp.Data[1])
-			pc.cursor(name)
-		case ops.TypeActionInput:
-			act := system.Action(encOp.Data[1])
-			pc.actionInputOp(act)
-		case ops.TypeKeyInputHint:
-			op := key.InputHintOp{
-				Tag:  encOp.Refs[0].(event.Tag),
-				Hint: key.InputHint(encOp.Data[1]),
-			}
-			s := q.stateFor(op.Tag)
-			s.key.inputHint(op.Hint)
-
-		// Semantic ops.
-		case ops.TypeSemanticLabel:
-			lbl := *encOp.Refs[0].(*string)
-			pc.semanticLabel(lbl)
-		case ops.TypeSemanticDesc:
-			desc := *encOp.Refs[0].(*string)
-			pc.semanticDesc(desc)
-		case ops.TypeSemanticClass:
-			class := semantic.ClassOp(encOp.Data[1])
-			pc.semanticClass(class)
-		case ops.TypeSemanticSelected:
-			if encOp.Data[1] != 0 {
-				pc.semanticSelected(true)
-			} else {
-				pc.semanticSelected(false)
-			}
-		case ops.TypeSemanticEnabled:
-			if encOp.Data[1] != 0 {
-				pc.semanticEnabled(true)
-			} else {
-				pc.semanticEnabled(false)
-			}
-		}
-	}
-}
-
-// WakeupTime returns the most recent time for doing another frame,
-// as determined from the last call to Frame.
-func (q *Router) WakeupTime() (time.Time, bool) {
-	t, w := q.wakeupTime, q.wakeup
-	q.wakeup = false
-	// Pending events always trigger wakeups.
-	if len(q.changes) > 1 || len(q.changes) == 1 && len(q.changes[0].events) > 0 {
-		t, w = time.Time{}, true
-	}
-	return t, w
-}
-
-func (s SemanticGestures) String() string {
-	var gestures []string
-	if s&ClickGesture != 0 {
-		gestures = append(gestures, "Click")
-	}
-	return strings.Join(gestures, ",")
-}
-
-func (SystemEvent) ImplementsEvent() {}

io/input/router_test.go

@@ -1,34 +0,0 @@
-// SPDX-License-Identifier: Unlicense OR MIT
-
-package input
-
-import (
-	"testing"
-
-	"gioui.org/io/pointer"
-	"gioui.org/op"
-)
-
-func TestNoFilterAllocs(t *testing.T) {
-	b := testing.Benchmark(func(b *testing.B) {
-		var r Router
-		s := r.Source()
-		b.ReportAllocs()
-		b.ResetTimer()
-		for i := 0; i < b.N; i++ {
-			s.Event(pointer.Filter{})
-		}
-	})
-	if allocs := b.AllocsPerOp(); allocs != 0 {
-		t.Fatalf("expected 0 AllocsPerOp, got %d", allocs)
-	}
-}
-
-func TestRouterWakeup(t *testing.T) {
-	r := new(Router)
-	r.Source().Execute(op.InvalidateCmd{})
-	r.Frame(new(op.Ops))
-	if _, wake := r.WakeupTime(); !wake {
-		t.Errorf("InvalidateCmd did not trigger a redraw")
-	}
-}

io/key/key.go

@@ -1,9 +1,18 @@
 // SPDX-License-Identifier: Unlicense OR MIT
 
-// Package key implements key and text events and operations.
+/*
+Package key implements key and text events and operations.
+
+The InputOp operations is used for declaring key input handlers. Use
+an implementation of the Queue interface from package ui to receive
+events.
+*/
 package key
 
 import (
+	"encoding/binary"
+	"fmt"
+	"math"
 	"strings"
 
 	"gioui.org/f32"
@@ -12,40 +21,59 @@ import (
 	"gioui.org/op"
 )
 
-// Filter matches any [Event] that matches the parameters.
+// InputOp declares a handler ready for key events.
-type Filter struct {
+// Key events are in general only delivered to the
-	// Focus is the tag that must be focused for the filter to match. It has no effect
+// focused key handler.
-	// if it is nil.
+type InputOp struct {
-	Focus event.Tag
+	Tag event.Tag
-	// Required is the set of modifiers that must be included in events matched.
+	// Hint describes the type of text expected by Tag.
-	Required Modifiers
-	// Optional is the set of modifiers that may be included in events matched.
-	Optional Modifiers
-	// Name of the key to be matched. As a special case, the empty
-	// Name matches every key not matched by any other filter.
-	Name Name
-}
-
-// InputHintOp describes the type of text expected by a tag.
-type InputHintOp struct {
-	Tag  event.Tag
 	Hint InputHint
+	// Keys is the set of keys Tag can handle. That is, Tag will only
+	// receive an Event if its key and modifiers are accepted by Keys.Contains.
+	// As a special case, the topmost (first added) InputOp handler receives all
+	// unhandled events.
+	Keys Set
 }
 
-// SoftKeyboardCmd shows or hides the on-screen keyboard, if available.
+// Set is an expression that describes a set of key combinations, in the form
-type SoftKeyboardCmd struct {
+// "<modifiers>-<keyset>|...".  Modifiers are separated by dashes, optional
+// modifiers are enclosed by parentheses.  A key set is either a literal key
+// name or a list of key names separated by commas and enclosed in brackets.
+//
+// The "Short" modifier matches the shortcut modifier (ModShortcut) and
+// "ShortAlt" matches the alternative modifier (ModShortcutAlt).
+//
+// Examples:
+//
+//   - A|B matches the A and B keys
+//   - [A,B] also matches the A and B keys
+//   - Shift-A matches A key if shift is pressed, and no other modifier.
+//   - Shift-(Ctrl)-A matches A if shift is pressed, and optionally ctrl.
+type Set string
+
+// SoftKeyboardOp shows or hide the on-screen keyboard, if available.
+// It replaces any previous SoftKeyboardOp.
+type SoftKeyboardOp struct {
 	Show bool
 }
 
-// SelectionCmd updates the selection for an input handler.
+// FocusOp sets or clears the keyboard focus. It replaces any previous
-type SelectionCmd struct {
+// FocusOp in the same frame.
+type FocusOp struct {
+	// Tag is the new focus. The focus is cleared if Tag is nil, or if Tag
+	// has no InputOp in the same frame.
+	Tag event.Tag
+}
+
+// SelectionOp updates the selection for an input handler.
+type SelectionOp struct {
 	Tag event.Tag
 	Range
 	Caret
 }
 
-// SnippetCmd updates the content snippet for an input handler.
+// SnippetOp updates the content snippet for an input handler.
-type SnippetCmd struct {
+type SnippetOp struct {
 	Tag event.Tag
 	Snippet
 }
@@ -90,8 +118,11 @@ type FocusEvent struct {
 // An Event is generated when a key is pressed. For text input
 // use EditEvent.
 type Event struct {
-	// Name of the key.
+	// Name of the key. For letters, the upper case form is used, via
-	Name Name
+	// unicode.ToUpper. The shift modifier is taken into account, all other
+	// modifiers are ignored. For example, the "shift-1" and "ctrl-shift-1"
+	// combinations both give the Name "!" with the US keyboard layout.
+	Name string
 	// Modifiers is the set of active modifiers when the key was pressed.
 	Modifiers Modifiers
 	// State is the state of the key when the event was fired.
@@ -105,13 +136,6 @@ type EditEvent struct {
 	Text  string
 }
 
-// FocusFilter matches any [FocusEvent], [EditEvent], [SnippetEvent],
-// or [SelectionEvent] with the specified target.
-type FocusFilter struct {
-	// Target is a tag specified in a previous event.Op.
-	Target event.Tag
-}
-
 // InputHint changes the on-screen-keyboard type. That hints the
 // type of data that might be entered by the user.
 type InputHint uint8
@@ -165,60 +189,41 @@ const (
 	ModSuper
 )
 
-// Name is the identifier for a keyboard key.
-//
-// For letters, the upper case form is used, via unicode.ToUpper.
-// The shift modifier is taken into account, all other
-// modifiers are ignored. For example, the "shift-1" and "ctrl-shift-1"
-// combinations both give the Name "!" with the US keyboard layout.
-type Name string
-
 const (
 	// Names for special keys.
-	NameLeftArrow      Name = "←"
+	NameLeftArrow      = "←"
-	NameRightArrow     Name = "→"
+	NameRightArrow     = "→"
-	NameUpArrow        Name = "↑"
+	NameUpArrow        = "↑"
-	NameDownArrow      Name = "↓"
+	NameDownArrow      = "↓"
-	NameReturn         Name = "⏎"
+	NameReturn         = "⏎"
-	NameEnter          Name = "⌤"
+	NameEnter          = "⌤"
-	NameEscape         Name = "⎋"
+	NameEscape         = "⎋"
-	NameHome           Name = "⇱"
+	NameHome           = "⇱"
-	NameEnd            Name = "⇲"
+	NameEnd            = "⇲"
-	NameDeleteBackward Name = "⌫"
+	NameDeleteBackward = "⌫"
-	NameDeleteForward  Name = "⌦"
+	NameDeleteForward  = "⌦"
-	NamePageUp         Name = "⇞"
+	NamePageUp         = "⇞"
-	NamePageDown       Name = "⇟"
+	NamePageDown       = "⇟"
-	NameTab            Name = "Tab"
+	NameTab            = "Tab"
-	NameSpace          Name = "Space"
+	NameSpace          = "Space"
-	NameCtrl           Name = "Ctrl"
+	NameCtrl           = "Ctrl"
-	NameShift          Name = "Shift"
+	NameShift          = "Shift"
-	NameAlt            Name = "Alt"
+	NameAlt            = "Alt"
-	NameSuper          Name = "Super"
+	NameSuper          = "Super"
-	NameCommand        Name = "⌘"
+	NameCommand        = "⌘"
-	NameF1             Name = "F1"
+	NameF1             = "F1"
-	NameF2             Name = "F2"
+	NameF2             = "F2"
-	NameF3             Name = "F3"
+	NameF3             = "F3"
-	NameF4             Name = "F4"
+	NameF4             = "F4"
-	NameF5             Name = "F5"
+	NameF5             = "F5"
-	NameF6             Name = "F6"
+	NameF6             = "F6"
-	NameF7             Name = "F7"
+	NameF7             = "F7"
-	NameF8             Name = "F8"
+	NameF8             = "F8"
-	NameF9             Name = "F9"
+	NameF9             = "F9"
-	NameF10            Name = "F10"
+	NameF10            = "F10"
-	NameF11            Name = "F11"
+	NameF11            = "F11"
-	NameF12            Name = "F12"
+	NameF12            = "F12"
-	NameBack           Name = "Back"
+	NameBack           = "Back"
-)
-
-type FocusDirection int
-
-const (
-	FocusRight FocusDirection = iota
-	FocusLeft
-	FocusUp
-	FocusDown
-	FocusForward
-	FocusBackward
 )
 
 // Contain reports whether m contains all modifiers
@@ -227,52 +232,161 @@ func (m Modifiers) Contain(m2 Modifiers) bool {
 	return m&m2 == m2
 }
 
-// FocusCmd requests to set or clear the keyboard focus.
+func (k Set) Contains(name string, mods Modifiers) bool {
-type FocusCmd struct {
+	ks := string(k)
-	// Tag is the new focus. The focus is cleared if Tag is nil, or if Tag
+	for len(ks) > 0 {
-	// has no [event.Op] references.
+		// Cut next key expression.
-	Tag event.Tag
+		chord, rest, _ := cut(ks, "|")
+		ks = rest
+		// Separate key set and modifier set.
+		var modSet, keySet string
+		sep := strings.LastIndex(chord, "-")
+		if sep != -1 {
+			modSet, keySet = chord[:sep], chord[sep+1:]
+		} else {
+			modSet, keySet = "", chord
+		}
+		if !keySetContains(keySet, name) {
+			continue
+		}
+		if modSetContains(modSet, mods) {
+			return true
+		}
+	}
+	return false
 }
 
-func (h InputHintOp) Add(o *op.Ops) {
+func keySetContains(keySet, name string) bool {
+	// Check for single key match.
+	if keySet == name {
+		return true
+	}
+	// Check for set match.
+	if len(keySet) < 2 || keySet[0] != '[' || keySet[len(keySet)-1] != ']' {
+		return false
+	}
+	keySet = keySet[1 : len(keySet)-1]
+	for len(keySet) > 0 {
+		key, rest, _ := cut(keySet, ",")
+		keySet = rest
+		if key == name {
+			return true
+		}
+	}
+	return false
+}
+
+func modSetContains(modSet string, mods Modifiers) bool {
+	var smods Modifiers
+	for len(modSet) > 0 {
+		mod, rest, _ := cut(modSet, "-")
+		modSet = rest
+		if len(mod) >= 2 && mod[0] == '(' && mod[len(mod)-1] == ')' {
+			mods &^= modFor(mod[1 : len(mod)-1])
+		} else {
+			smods |= modFor(mod)
+		}
+	}
+	return mods == smods
+}
+
+// cut is a copy of the standard library strings.Cut.
+// TODO: remove when Go 1.18 is our minimum.
+func cut(s, sep string) (before, after string, found bool) {
+	if i := strings.Index(s, sep); i >= 0 {
+		return s[:i], s[i+len(sep):], true
+	}
+	return s, "", false
+}
+
+func modFor(name string) Modifiers {
+	switch name {
+	case NameCtrl:
+		return ModCtrl
+	case NameShift:
+		return ModShift
+	case NameAlt:
+		return ModAlt
+	case NameSuper:
+		return ModSuper
+	case NameCommand:
+		return ModCommand
+	case "Short":
+		return ModShortcut
+	case "ShortAlt":
+		return ModShortcutAlt
+	}
+	return 0
+}
+
+func (h InputOp) Add(o *op.Ops) {
 	if h.Tag == nil {
 		panic("Tag must be non-nil")
 	}
-	data := ops.Write1(&o.Internal, ops.TypeKeyInputHintLen, h.Tag)
+	data := ops.Write2String(&o.Internal, ops.TypeKeyInputLen, h.Tag, string(h.Keys))
-	data[0] = byte(ops.TypeKeyInputHint)
+	data[0] = byte(ops.TypeKeyInput)
 	data[1] = byte(h.Hint)
 }
 
+func (h SoftKeyboardOp) Add(o *op.Ops) {
+	data := ops.Write(&o.Internal, ops.TypeKeySoftKeyboardLen)
+	data[0] = byte(ops.TypeKeySoftKeyboard)
+	if h.Show {
+		data[1] = 1
+	}
+}
+
+func (h FocusOp) Add(o *op.Ops) {
+	data := ops.Write1(&o.Internal, ops.TypeKeyFocusLen, h.Tag)
+	data[0] = byte(ops.TypeKeyFocus)
+}
+
+func (s SnippetOp) Add(o *op.Ops) {
+	data := ops.Write2String(&o.Internal, ops.TypeSnippetLen, s.Tag, s.Text)
+	data[0] = byte(ops.TypeSnippet)
+	bo := binary.LittleEndian
+	bo.PutUint32(data[1:], uint32(s.Range.Start))
+	bo.PutUint32(data[5:], uint32(s.Range.End))
+}
+
+func (s SelectionOp) Add(o *op.Ops) {
+	data := ops.Write1(&o.Internal, ops.TypeSelectionLen, s.Tag)
+	data[0] = byte(ops.TypeSelection)
+	bo := binary.LittleEndian
+	bo.PutUint32(data[1:], uint32(s.Start))
+	bo.PutUint32(data[5:], uint32(s.End))
+	bo.PutUint32(data[9:], math.Float32bits(s.Pos.X))
+	bo.PutUint32(data[13:], math.Float32bits(s.Pos.Y))
+	bo.PutUint32(data[17:], math.Float32bits(s.Ascent))
+	bo.PutUint32(data[21:], math.Float32bits(s.Descent))
+}
+
 func (EditEvent) ImplementsEvent()      {}
 func (Event) ImplementsEvent()          {}
 func (FocusEvent) ImplementsEvent()     {}
 func (SnippetEvent) ImplementsEvent()   {}
 func (SelectionEvent) ImplementsEvent() {}
 
-func (FocusCmd) ImplementsCommand()        {}
+func (e Event) String() string {
-func (SoftKeyboardCmd) ImplementsCommand() {}
+	return fmt.Sprintf("%v %v %v}", e.Name, e.Modifiers, e.State)
-func (SelectionCmd) ImplementsCommand()    {}
+}
-func (SnippetCmd) ImplementsCommand()      {}
-
-func (Filter) ImplementsFilter()      {}
-func (FocusFilter) ImplementsFilter() {}
 
 func (m Modifiers) String() string {
 	var strs []string
 	if m.Contain(ModCtrl) {
-		strs = append(strs, string(NameCtrl))
+		strs = append(strs, NameCtrl)
 	}
 	if m.Contain(ModCommand) {
-		strs = append(strs, string(NameCommand))
+		strs = append(strs, NameCommand)
 	}
 	if m.Contain(ModShift) {
-		strs = append(strs, string(NameShift))
+		strs = append(strs, NameShift)
 	}
 	if m.Contain(ModAlt) {
-		strs = append(strs, string(NameAlt))
+		strs = append(strs, NameAlt)
 	}
 	if m.Contain(ModSuper) {
-		strs = append(strs, string(NameSuper))
+		strs = append(strs, NameSuper)
 	}
 	return strings.Join(strs, "-")
 }

io/key/key_test.go

@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package key
+
+import (
+	"testing"
+)
+
+func TestKeySet(t *testing.T) {
+	const allMods = ModAlt | ModShift | ModSuper | ModCtrl | ModCommand
+	tests := []struct {
+		Set        Set
+		Matches    []Event
+		Mismatches []Event
+	}{
+		{"A", []Event{{Name: "A"}}, []Event{{Name: "A", Modifiers: ModShift}}},
+		{"[A,B,C]", []Event{{Name: "A"}, {Name: "B"}}, []Event{}},
+		{"Short-A", []Event{{Name: "A", Modifiers: ModShortcut}}, []Event{{Name: "A", Modifiers: ModShift}}},
+		{"(Ctrl)-A", []Event{{Name: "A", Modifiers: ModCtrl}, {Name: "A"}}, []Event{{Name: "A", Modifiers: ModShift}}},
+		{"Shift-[A,B,C]", []Event{{Name: "A", Modifiers: ModShift}}, []Event{{Name: "B", Modifiers: ModShift | ModCtrl}}},
+		{Set(allMods.String() + "-A"), []Event{{Name: "A", Modifiers: allMods}}, []Event{}},
+	}
+	for _, tst := range tests {
+		for _, e := range tst.Matches {
+			if !tst.Set.Contains(e.Name, e.Modifiers) {
+				t.Errorf("key set %q didn't contain %+v", tst.Set, e)
+			}
+		}
+		for _, e := range tst.Mismatches {
+			if tst.Set.Contains(e.Name, e.Modifiers) {
+				t.Errorf("key set %q contains %+v", tst.Set, e)
+			}
+		}
+	}
+}

io/pointer/doc.go

@@ -5,19 +5,36 @@ Package pointer implements pointer events and operations.
 A pointer is either a mouse controlled cursor or a touch
 object such as a finger.
 
-The [event.Op] operation is used to declare a handler ready for pointer
+The InputOp operation is used to declare a handler ready for pointer
-events.
+events. Use an event.Queue to receive events.
+
+# Kinds
+
+Only events that match a specified list of types are delivered to a handler.
+
+For example, to receive Press, Drag, and Release events (but not Move, Enter,
+Leave, or Scroll):
+
+	var ops op.Ops
+	var h *Handler = ...
+
+	pointer.InputOp{
+		Tag:   h,
+		Kinds: pointer.Press | pointer.Drag | pointer.Release,
+	}.Add(ops)
+
+Cancel events are always delivered.
 
 # Hit areas
 
-Clip operations from package [op/clip] are used for specifying
+Clip operations from package op/clip are used for specifying
-hit areas where handlers may receive events.
+hit areas where subsequent InputOps are active.
 
 For example, to set up a handler with a rectangular hit area:
 
 	r := image.Rectangle{...}
 	area := clip.Rect(r).Push(ops)
-	event.Op{Tag: h}.Add(ops)
+	pointer.InputOp{Tag: h}.Add(ops)
 	area.Pop()
 
 Note that hit areas behave similar to painting: the effective area of a stack
@@ -37,11 +54,11 @@ For example:
 	var h1, h2 *Handler
 
 	area := clip.Rect(...).Push(ops)
-	event.Op{Tag: h1}.Add(Ops)
+	pointer.InputOp{Tag: h1}.Add(Ops)
 	area.Pop()
 
 	area := clip.Rect(...).Push(ops)
-	event.Op{Tag: h2}.Add(ops)
+	pointer.InputOp{Tag: h2}.Add(ops)
 	area.Pop()
 
 implies a tree of two inner nodes, each with one pointer handler attached.

io/pointer/pointer.go

@@ -3,6 +3,8 @@
 package pointer
 
 import (
+	"encoding/binary"
+	"fmt"
 	"image"
 	"strings"
 	"time"
@@ -54,12 +56,14 @@ type PassStack struct {
 	macroID uint32
 }
 
-// Filter matches every [Event] that target the Tag and whose kind is
+// InputOp declares an input handler ready for pointer
-// included in Kinds. Note that only tags specified in [event.Op] can
+// events.
-// be targeted by pointer events.
+type InputOp struct {
-type Filter struct {
+	Tag event.Tag
-	Target event.Tag
+	// Grab, if set, request that the handler get
-	// Kinds is a bitwise-or of event types to match.
+	// Grabbed priority.
+	Grab bool
+	// Kinds is a bitwise-or of event types to receive.
 	Kinds Kind
 	// ScrollBounds describe the maximum scrollable distances in both
 	// axes. Specifically, any Event e delivered to Tag will satisfy
@@ -69,12 +73,6 @@ type Filter struct {
 	ScrollBounds image.Rectangle
 }
 
-// GrabCmd requests a pointer grab on the pointer identified by ID.
-type GrabCmd struct {
-	Tag event.Tag
-	ID  ID
-}
-
 type ID uint16
 
 // Kind of an Event.
@@ -173,7 +171,7 @@ const (
 const (
 	// A Cancel event is generated when the current gesture is
 	// interrupted by other handlers or the system.
-	Cancel Kind = 1 << iota
+	Cancel Kind = (1 << iota) >> 1
 	// Press of a pointer.
 	Press
 	// Release of a pointer.
@@ -239,6 +237,30 @@ func (op Cursor) Add(o *op.Ops) {
 	data[1] = byte(op)
 }
 
+// Add panics if the scroll range does not contain zero.
+func (op InputOp) Add(o *op.Ops) {
+	if op.Tag == nil {
+		panic("Tag must be non-nil")
+	}
+	if b := op.ScrollBounds; b.Min.X > 0 || b.Max.X < 0 || b.Min.Y > 0 || b.Max.Y < 0 {
+		panic(fmt.Errorf("invalid scroll range value %v", b))
+	}
+	if op.Kinds>>16 > 0 {
+		panic(fmt.Errorf("value in Types overflows uint16"))
+	}
+	data := ops.Write1(&o.Internal, ops.TypePointerInputLen, op.Tag)
+	data[0] = byte(ops.TypePointerInput)
+	if op.Grab {
+		data[1] = 1
+	}
+	bo := binary.LittleEndian
+	bo.PutUint16(data[2:], uint16(op.Kinds))
+	bo.PutUint32(data[4:], uint32(op.ScrollBounds.Min.X))
+	bo.PutUint32(data[8:], uint32(op.ScrollBounds.Min.Y))
+	bo.PutUint32(data[12:], uint32(op.ScrollBounds.Max.X))
+	bo.PutUint32(data[16:], uint32(op.ScrollBounds.Max.Y))
+}
+
 func (t Kind) String() string {
 	if t == Cancel {
 		return "Cancel"
@@ -382,7 +404,3 @@ func (c Cursor) String() string {
 }
 
 func (Event) ImplementsEvent() {}
-
-func (GrabCmd) ImplementsCommand() {}
-
-func (Filter) ImplementsFilter() {}

io/profile/profile.go

@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+// Package profiles provides access to rendering
+// profiles.
+package profile
+
+import (
+	"gioui.org/internal/ops"
+	"gioui.org/io/event"
+	"gioui.org/op"
+)
+
+// Op registers a handler for receiving
+// Events.
+type Op struct {
+	Tag event.Tag
+}
+
+// Event contains profile data from a single
+// rendered frame.
+type Event struct {
+	// Timings. Very likely to change.
+	Timings string
+}
+
+func (p Op) Add(o *op.Ops) {
+	data := ops.Write1(&o.Internal, ops.TypeProfileLen, p.Tag)
+	data[0] = byte(ops.TypeProfile)
+}
+
+func (p Event) ImplementsEvent() {}

io/router/clipboard.go

@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package router
+
+import (
+	"gioui.org/io/event"
+)
+
+type clipboardQueue struct {
+	receivers map[event.Tag]struct{}
+	// request avoid read clipboard every frame while waiting.
+	requested bool
+	text      *string
+}
+
+// WriteClipboard returns the most recent text to be copied
+// to the clipboard, if any.
+func (q *clipboardQueue) WriteClipboard() (string, bool) {
+	if q.text == nil {
+		return "", false
+	}
+	text := *q.text
+	q.text = nil
+	return text, true
+}
+
+// ReadClipboard reports if any new handler is waiting
+// to read the clipboard.
+func (q *clipboardQueue) ReadClipboard() bool {
+	if len(q.receivers) == 0 || q.requested {
+		return false
+	}
+	q.requested = true
+	return true
+}
+
+func (q *clipboardQueue) Push(e event.Event, events *handlerEvents) {
+	for r := range q.receivers {
+		events.Add(r, e)
+		delete(q.receivers, r)
+	}
+}
+
+func (q *clipboardQueue) ProcessWriteClipboard(refs []interface{}) {
+	q.text = refs[0].(*string)
+}
+
+func (q *clipboardQueue) ProcessReadClipboard(refs []interface{}) {
+	if q.receivers == nil {
+		q.receivers = make(map[event.Tag]struct{})
+	}
+	tag := refs[0].(event.Tag)
+	if _, ok := q.receivers[tag]; !ok {
+		q.receivers[tag] = struct{}{}
+		q.requested = false
+	}
+}

io/router/clipboard_test.go

@@ -0,0 +1,154 @@
+package router
+
+import (
+	"testing"
+
+	"gioui.org/io/clipboard"
+	"gioui.org/io/event"
+	"gioui.org/op"
+)
+
+func TestClipboardDuplicateEvent(t *testing.T) {
+	ops, router, handler := new(op.Ops), new(Router), make([]int, 2)
+
+	// Both must receive the event once
+	clipboard.ReadOp{Tag: &handler[0]}.Add(ops)
+	clipboard.ReadOp{Tag: &handler[1]}.Add(ops)
+
+	router.Frame(ops)
+	event := clipboard.Event{Text: "Test"}
+	router.Queue(event)
+	assertClipboardReadOp(t, router, 0)
+	assertClipboardEvent(t, router.Events(&handler[0]), true)
+	assertClipboardEvent(t, router.Events(&handler[1]), true)
+	ops.Reset()
+
+	// No ReadOp
+
+	router.Frame(ops)
+	assertClipboardReadOp(t, router, 0)
+	assertClipboardEvent(t, router.Events(&handler[0]), false)
+	assertClipboardEvent(t, router.Events(&handler[1]), false)
+	ops.Reset()
+
+	clipboard.ReadOp{Tag: &handler[0]}.Add(ops)
+
+	router.Frame(ops)
+	// No ClipboardEvent sent
+	assertClipboardReadOp(t, router, 1)
+	assertClipboardEvent(t, router.Events(&handler[0]), false)
+	assertClipboardEvent(t, router.Events(&handler[1]), false)
+	ops.Reset()
+}
+
+func TestQueueProcessReadClipboard(t *testing.T) {
+	ops, router, handler := new(op.Ops), new(Router), make([]int, 2)
+	ops.Reset()
+
+	// Request read
+	clipboard.ReadOp{Tag: &handler[0]}.Add(ops)
+
+	router.Frame(ops)
+	assertClipboardReadOp(t, router, 1)
+	ops.Reset()
+
+	for i := 0; i < 3; i++ {
+		// No ReadOp
+		// One receiver must still wait for response
+
+		router.Frame(ops)
+		assertClipboardReadOpDuplicated(t, router, 1)
+		ops.Reset()
+	}
+
+	router.Frame(ops)
+	// Send the clipboard event
+	event := clipboard.Event{Text: "Text 2"}
+	router.Queue(event)
+	assertClipboardReadOp(t, router, 0)
+	assertClipboardEvent(t, router.Events(&handler[0]), true)
+	ops.Reset()
+
+	// No ReadOp
+	// There's no receiver waiting
+
+	router.Frame(ops)
+	assertClipboardReadOp(t, router, 0)
+	assertClipboardEvent(t, router.Events(&handler[0]), false)
+	ops.Reset()
+}
+
+func TestQueueProcessWriteClipboard(t *testing.T) {
+	ops, router := new(op.Ops), new(Router)
+	ops.Reset()
+
+	clipboard.WriteOp{Text: "Write 1"}.Add(ops)
+
+	router.Frame(ops)
+	assertClipboardWriteOp(t, router, "Write 1")
+	ops.Reset()
+
+	// No WriteOp
+
+	router.Frame(ops)
+	assertClipboardWriteOp(t, router, "")
+	ops.Reset()
+
+	clipboard.WriteOp{Text: "Write 2"}.Add(ops)
+
+	router.Frame(ops)
+	assertClipboardReadOp(t, router, 0)
+	assertClipboardWriteOp(t, router, "Write 2")
+	ops.Reset()
+}
+
+func assertClipboardEvent(t *testing.T, events []event.Event, expected bool) {
+	t.Helper()
+	var evtClipboard int
+	for _, e := range events {
+		switch e.(type) {
+		case clipboard.Event:
+			evtClipboard++
+		}
+	}
+	if evtClipboard <= 0 && expected {
+		t.Error("expected to receive some event")
+	}
+	if evtClipboard > 0 && !expected {
+		t.Error("unexpected event received")
+	}
+}
+
+func assertClipboardReadOp(t *testing.T, router *Router, expected int) {
+	t.Helper()
+	if len(router.cqueue.receivers) != expected {
+		t.Error("unexpected number of receivers")
+	}
+	if router.cqueue.ReadClipboard() != (expected > 0) {
+		t.Error("missing requests")
+	}
+}
+
+func assertClipboardReadOpDuplicated(t *testing.T, router *Router, expected int) {
+	t.Helper()
+	if len(router.cqueue.receivers) != expected {
+		t.Error("receivers removed")
+	}
+	if router.cqueue.ReadClipboard() != false {
+		t.Error("duplicated requests")
+	}
+}
+
+func assertClipboardWriteOp(t *testing.T, router *Router, expected string) {
+	t.Helper()
+	if (router.cqueue.text != nil) != (expected != "") {
+		t.Error("text not defined")
+	}
+	text, ok := router.cqueue.WriteClipboard()
+	if ok != (expected != "") {
+		t.Error("duplicated requests")
+	}
+	if text != expected {
+		t.Errorf("got text %s, expected %s", text, expected)
+	}
+}

io/router/key.go

@@ -0,0 +1,353 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package router
+
+import (
+	"image"
+	"sort"
+
+	"gioui.org/f32"
+	"gioui.org/io/event"
+	"gioui.org/io/key"
+)
+
+// EditorState represents the state of an editor needed by input handlers.
+type EditorState struct {
+	Selection struct {
+		Transform f32.Affine2D
+		key.Range
+		key.Caret
+	}
+	Snippet key.Snippet
+}
+
+type TextInputState uint8
+
+type keyQueue struct {
+	focus    event.Tag
+	order    []event.Tag
+	dirOrder []dirFocusEntry
+	handlers map[event.Tag]*keyHandler
+	state    TextInputState
+	hint     key.InputHint
+	content  EditorState
+}
+
+type keyHandler struct {
+	// visible will be true if the InputOp is present
+	// in the current frame.
+	visible  bool
+	new      bool
+	hint     key.InputHint
+	order    int
+	dirOrder int
+	filter   key.Set
+}
+
+// keyCollector tracks state required to update a keyQueue
+// from key ops.
+type keyCollector struct {
+	q       *keyQueue
+	focus   event.Tag
+	changed bool
+}
+
+type dirFocusEntry struct {
+	tag    event.Tag
+	row    int
+	area   int
+	bounds image.Rectangle
+}
+
+const (
+	TextInputKeep TextInputState = iota
+	TextInputClose
+	TextInputOpen
+)
+
+type FocusDirection int
+
+const (
+	FocusRight FocusDirection = iota
+	FocusLeft
+	FocusUp
+	FocusDown
+	FocusForward
+	FocusBackward
+)
+
+// InputState returns the last text input state as
+// determined in Frame.
+func (q *keyQueue) InputState() TextInputState {
+	state := q.state
+	q.state = TextInputKeep
+	return state
+}
+
+// InputHint returns the input mode from the most recent key.InputOp.
+func (q *keyQueue) InputHint() (key.InputHint, bool) {
+	if q.focus == nil {
+		return q.hint, false
+	}
+	focused, ok := q.handlers[q.focus]
+	if !ok {
+		return q.hint, false
+	}
+	old := q.hint
+	q.hint = focused.hint
+	return q.hint, old != q.hint
+}
+
+func (q *keyQueue) Reset() {
+	if q.handlers == nil {
+		q.handlers = make(map[event.Tag]*keyHandler)
+	}
+	for _, h := range q.handlers {
+		h.visible, h.new = false, false
+		h.order = -1
+	}
+	q.order = q.order[:0]
+	q.dirOrder = q.dirOrder[:0]
+}
+
+func (q *keyQueue) Frame(events *handlerEvents, collector keyCollector) {
+	changed, focus := collector.changed, collector.focus
+	for k, h := range q.handlers {
+		if !h.visible {
+			delete(q.handlers, k)
+			if q.focus == k {
+				// Remove focus from the handler that is no longer visible.
+				q.focus = nil
+				q.state = TextInputClose
+			}
+		} else if h.new && k != focus {
+			// Reset the handler on (each) first appearance, but don't trigger redraw.
+			events.AddNoRedraw(k, key.FocusEvent{Focus: false})
+		}
+	}
+	if changed {
+		q.setFocus(focus, events)
+	}
+	q.updateFocusLayout()
+}
+
+// updateFocusLayout partitions input handlers handlers into rows
+// for directional focus moves.
+//
+// The approach is greedy: pick the topmost handler and create a row
+// containing it. Then, extend the handler bounds to a horizontal beam
+// and add to the row every handler whose center intersect it. Repeat
+// until no handlers remain.
+func (q *keyQueue) updateFocusLayout() {
+	order := q.dirOrder
+	// Sort by ascending y position.
+	sort.SliceStable(order, func(i, j int) bool {
+		return order[i].bounds.Min.Y < order[j].bounds.Min.Y
+	})
+	row := 0
+	for len(order) > 0 {
+		h := &order[0]
+		h.row = row
+		bottom := h.bounds.Max.Y
+		end := 1
+		for ; end < len(order); end++ {
+			h := &order[end]
+			center := (h.bounds.Min.Y + h.bounds.Max.Y) / 2
+			if center > bottom {
+				break
+			}
+			h.row = row
+		}
+		// Sort row by ascending x position.
+		sort.SliceStable(order[:end], func(i, j int) bool {
+			return order[i].bounds.Min.X < order[j].bounds.Min.X
+		})
+		order = order[end:]
+		row++
+	}
+	for i, o := range q.dirOrder {
+		q.handlers[o.tag].dirOrder = i
+	}
+}
+
+// MoveFocus attempts to move the focus in the direction of dir, returning true if it succeeds.
+func (q *keyQueue) MoveFocus(dir FocusDirection, events *handlerEvents) bool {
+	if len(q.dirOrder) == 0 {
+		return false
+	}
+	order := 0
+	if q.focus != nil {
+		order = q.handlers[q.focus].dirOrder
+	}
+	focus := q.dirOrder[order]
+	switch dir {
+	case FocusForward, FocusBackward:
+		if len(q.order) == 0 {
+			break
+		}
+		order := 0
+		if dir == FocusBackward {
+			order = -1
+		}
+		if q.focus != nil {
+			order = q.handlers[q.focus].order
+			if dir == FocusForward {
+				order++
+			} else {
+				order--
+			}
+		}
+		order = (order + len(q.order)) % len(q.order)
+		q.setFocus(q.order[order], events)
+		return true
+	case FocusRight, FocusLeft:
+		next := order
+		if q.focus != nil {
+			next = order + 1
+			if dir == FocusLeft {
+				next = order - 1
+			}
+		}
+		if 0 <= next && next < len(q.dirOrder) {
+			newFocus := q.dirOrder[next]
+			if newFocus.row == focus.row {
+				q.setFocus(newFocus.tag, events)
+				return true
+			}
+		}
+	case FocusUp, FocusDown:
+		delta := +1
+		if dir == FocusUp {
+			delta = -1
+		}
+		nextRow := 0
+		if q.focus != nil {
+			nextRow = focus.row + delta
+		}
+		var closest event.Tag
+		dist := int(1e6)
+		center := (focus.bounds.Min.X + focus.bounds.Max.X) / 2
+	loop:
+		for 0 <= order && order < len(q.dirOrder) {
+			next := q.dirOrder[order]
+			switch next.row {
+			case nextRow:
+				nextCenter := (next.bounds.Min.X + next.bounds.Max.X) / 2
+				d := center - nextCenter
+				if d < 0 {
+					d = -d
+				}
+				if d > dist {
+					break loop
+				}
+				dist = d
+				closest = next.tag
+			case nextRow + delta:
+				break loop
+			}
+			order += delta
+		}
+		if closest != nil {
+			q.setFocus(closest, events)
+			return true
+		}
+	}
+	return false
+}
+
+func (q *keyQueue) BoundsFor(t event.Tag) image.Rectangle {
+	order := q.handlers[t].dirOrder
+	return q.dirOrder[order].bounds
+}
+
+func (q *keyQueue) AreaFor(t event.Tag) int {
+	order := q.handlers[t].dirOrder
+	return q.dirOrder[order].area
+}
+
+func (q *keyQueue) Accepts(t event.Tag, e key.Event) bool {
+	return q.handlers[t].filter.Contains(e.Name, e.Modifiers)
+}
+
+func (q *keyQueue) setFocus(focus event.Tag, events *handlerEvents) {
+	if focus != nil {
+		if _, exists := q.handlers[focus]; !exists {
+			focus = nil
+		}
+	}
+	if focus == q.focus {
+		return
+	}
+	q.content = EditorState{}
+	if q.focus != nil {
+		events.Add(q.focus, key.FocusEvent{Focus: false})
+	}
+	q.focus = focus
+	if q.focus != nil {
+		events.Add(q.focus, key.FocusEvent{Focus: true})
+	}
+	if q.focus == nil || q.state == TextInputKeep {
+		q.state = TextInputClose
+	}
+}
+
+func (k *keyCollector) focusOp(tag event.Tag) {
+	k.focus = tag
+	k.changed = true
+}
+
+func (k *keyCollector) softKeyboard(show bool) {
+	if show {
+		k.q.state = TextInputOpen
+	} else {
+		k.q.state = TextInputClose
+	}
+}
+
+func (k *keyCollector) handlerFor(tag event.Tag, area int, bounds image.Rectangle) *keyHandler {
+	h, ok := k.q.handlers[tag]
+	if !ok {
+		h = &keyHandler{new: true, order: -1}
+		k.q.handlers[tag] = h
+	}
+	if h.order == -1 {
+		h.order = len(k.q.order)
+		k.q.order = append(k.q.order, tag)
+		k.q.dirOrder = append(k.q.dirOrder, dirFocusEntry{tag: tag, area: area, bounds: bounds})
+	}
+	return h
+}
+
+func (k *keyCollector) inputOp(op key.InputOp, area int, bounds image.Rectangle) {
+	h := k.handlerFor(op.Tag, area, bounds)
+	h.visible = true
+	h.hint = op.Hint
+	h.filter = op.Keys
+}
+
+func (k *keyCollector) selectionOp(t f32.Affine2D, op key.SelectionOp) {
+	if op.Tag == k.q.focus {
+		k.q.content.Selection.Range = op.Range
+		k.q.content.Selection.Caret = op.Caret
+		k.q.content.Selection.Transform = t
+	}
+}
+
+func (k *keyCollector) snippetOp(op key.SnippetOp) {
+	if op.Tag == k.q.focus {
+		k.q.content.Snippet = op.Snippet
+	}
+}
+
+func (t TextInputState) String() string {
+	switch t {
+	case TextInputKeep:
+		return "Keep"
+	case TextInputClose:
+		return "Close"
+	case TextInputOpen:
+		return "Open"
+	default:
+		panic("unexpected value")
+	}
+}

io/router/key_test.go

@@ -0,0 +1,427 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package router
+
+import (
+	"image"
+	"reflect"
+	"testing"
+
+	"gioui.org/f32"
+	"gioui.org/io/event"
+	"gioui.org/io/key"
+	"gioui.org/io/pointer"
+	"gioui.org/op"
+	"gioui.org/op/clip"
+)
+
+func TestKeyWakeup(t *testing.T) {
+	handler := new(int)
+	var ops op.Ops
+	key.InputOp{Tag: handler}.Add(&ops)
+
+	var r Router
+	// Test that merely adding a handler doesn't trigger redraw.
+	r.Frame(&ops)
+	if _, wake := r.WakeupTime(); wake {
+		t.Errorf("adding key.InputOp triggered a redraw")
+	}
+	// However, adding a handler queues a Focus(false) event.
+	if evts := r.Events(handler); len(evts) != 1 {
+		t.Errorf("no Focus event for newly registered key.InputOp")
+	}
+}
+
+func TestKeyMultiples(t *testing.T) {
+	handlers := make([]int, 3)
+	ops := new(op.Ops)
+	r := new(Router)
+
+	key.SoftKeyboardOp{Show: true}.Add(ops)
+	key.InputOp{Tag: &handlers[0]}.Add(ops)
+	key.FocusOp{Tag: &handlers[2]}.Add(ops)
+	key.InputOp{Tag: &handlers[1]}.Add(ops)
+
+	// The last one must be focused:
+	key.InputOp{Tag: &handlers[2]}.Add(ops)
+
+	r.Frame(ops)
+
+	assertKeyEvent(t, r.Events(&handlers[0]), false)
+	assertKeyEvent(t, r.Events(&handlers[1]), false)
+	assertKeyEvent(t, r.Events(&handlers[2]), true)
+	assertFocus(t, r, &handlers[2])
+	assertKeyboard(t, r, TextInputOpen)
+}
+
+func TestKeyStacked(t *testing.T) {
+	handlers := make([]int, 4)
+	ops := new(op.Ops)
+	r := new(Router)
+
+	key.InputOp{Tag: &handlers[0]}.Add(ops)
+	key.FocusOp{Tag: nil}.Add(ops)
+	key.SoftKeyboardOp{Show: false}.Add(ops)
+	key.InputOp{Tag: &handlers[1]}.Add(ops)
+	key.FocusOp{Tag: &handlers[1]}.Add(ops)
+	key.InputOp{Tag: &handlers[2]}.Add(ops)
+	key.SoftKeyboardOp{Show: true}.Add(ops)
+	key.InputOp{Tag: &handlers[3]}.Add(ops)
+
+	r.Frame(ops)
+
+	assertKeyEvent(t, r.Events(&handlers[0]), false)
+	assertKeyEvent(t, r.Events(&handlers[1]), true)
+	assertKeyEvent(t, r.Events(&handlers[2]), false)
+	assertKeyEvent(t, r.Events(&handlers[3]), false)
+	assertFocus(t, r, &handlers[1])
+	assertKeyboard(t, r, TextInputOpen)
+}
+
+func TestKeySoftKeyboardNoFocus(t *testing.T) {
+	ops := new(op.Ops)
+	r := new(Router)
+
+	// It's possible to open the keyboard
+	// without any active focus:
+	key.SoftKeyboardOp{Show: true}.Add(ops)
+
+	r.Frame(ops)
+
+	assertFocus(t, r, nil)
+	assertKeyboard(t, r, TextInputOpen)
+}
+
+func TestKeyRemoveFocus(t *testing.T) {
+	handlers := make([]int, 2)
+	ops := new(op.Ops)
+	r := new(Router)
+
+	// New InputOp with Focus and Keyboard:
+	key.InputOp{Tag: &handlers[0], Keys: "Short-Tab"}.Add(ops)
+	key.FocusOp{Tag: &handlers[0]}.Add(ops)
+	key.SoftKeyboardOp{Show: true}.Add(ops)
+
+	// New InputOp without any focus:
+	key.InputOp{Tag: &handlers[1], Keys: "Short-Tab"}.Add(ops)
+
+	r.Frame(ops)
+
+	// Add some key events:
+	event := event.Event(key.Event{Name: key.NameTab, Modifiers: key.ModShortcut, State: key.Press})
+	r.Queue(event)
+
+	assertKeyEvent(t, r.Events(&handlers[0]), true, event)
+	assertKeyEvent(t, r.Events(&handlers[1]), false)
+	assertFocus(t, r, &handlers[0])
+	assertKeyboard(t, r, TextInputOpen)
+
+	ops.Reset()
+
+	// Will get the focus removed:
+	key.InputOp{Tag: &handlers[0]}.Add(ops)
+
+	// Unchanged:
+	key.InputOp{Tag: &handlers[1]}.Add(ops)
+
+	// Remove focus by focusing on a tag that don't exist.
+	key.FocusOp{Tag: new(int)}.Add(ops)
+
+	r.Frame(ops)
+
+	assertKeyEventUnexpected(t, r.Events(&handlers[1]))
+	assertFocus(t, r, nil)
+	assertKeyboard(t, r, TextInputClose)
+
+	ops.Reset()
+
+	key.InputOp{Tag: &handlers[0]}.Add(ops)
+
+	key.InputOp{Tag: &handlers[1]}.Add(ops)
+
+	r.Frame(ops)
+
+	assertKeyEventUnexpected(t, r.Events(&handlers[0]))
+	assertKeyEventUnexpected(t, r.Events(&handlers[1]))
+	assertFocus(t, r, nil)
+	assertKeyboard(t, r, TextInputClose)
+
+	ops.Reset()
+
+	// Set focus to InputOp which already
+	// exists in the previous frame:
+	key.FocusOp{Tag: &handlers[0]}.Add(ops)
+	key.InputOp{Tag: &handlers[0]}.Add(ops)
+	key.SoftKeyboardOp{Show: true}.Add(ops)
+
+	// Remove focus.
+	key.InputOp{Tag: &handlers[1]}.Add(ops)
+	key.FocusOp{Tag: nil}.Add(ops)
+
+	r.Frame(ops)
+
+	assertKeyEventUnexpected(t, r.Events(&handlers[1]))
+	assertFocus(t, r, nil)
+	assertKeyboard(t, r, TextInputOpen)
+}
+
+func TestKeyFocusedInvisible(t *testing.T) {
+	handlers := make([]int, 2)
+	ops := new(op.Ops)
+	r := new(Router)
+
+	// Set new InputOp with focus:
+	key.FocusOp{Tag: &handlers[0]}.Add(ops)
+	key.InputOp{Tag: &handlers[0]}.Add(ops)
+	key.SoftKeyboardOp{Show: true}.Add(ops)
+
+	// Set new InputOp without focus:
+	key.InputOp{Tag: &handlers[1]}.Add(ops)
+
+	r.Frame(ops)
+
+	assertKeyEvent(t, r.Events(&handlers[0]), true)
+	assertKeyEvent(t, r.Events(&handlers[1]), false)
+	assertFocus(t, r, &handlers[0])
+	assertKeyboard(t, r, TextInputOpen)
+
+	ops.Reset()
+
+	//
+	// Removed first (focused) element!
+	//
+
+	// Unchanged:
+	key.InputOp{Tag: &handlers[1]}.Add(ops)
+
+	r.Frame(ops)
+
+	assertKeyEventUnexpected(t, r.Events(&handlers[0]))
+	assertKeyEventUnexpected(t, r.Events(&handlers[1]))
+	assertFocus(t, r, nil)
+	assertKeyboard(t, r, TextInputClose)
+
+	ops.Reset()
+
+	// Respawn the first element:
+	// It must receive one `Event{Focus: false}`.
+	key.InputOp{Tag: &handlers[0]}.Add(ops)
+
+	// Unchanged
+	key.InputOp{Tag: &handlers[1]}.Add(ops)
+
+	r.Frame(ops)
+
+	assertKeyEvent(t, r.Events(&handlers[0]), false)
+	assertKeyEventUnexpected(t, r.Events(&handlers[1]))
+	assertFocus(t, r, nil)
+	assertKeyboard(t, r, TextInputClose)
+
+}
+
+func TestNoOps(t *testing.T) {
+	r := new(Router)
+	r.Frame(nil)
+}
+
+func TestDirectionalFocus(t *testing.T) {
+	ops := new(op.Ops)
+	r := new(Router)
+	handlers := []image.Rectangle{
+		image.Rect(10, 10, 50, 50),
+		image.Rect(50, 20, 100, 80),
+		image.Rect(20, 26, 60, 80),
+		image.Rect(10, 60, 50, 100),
+	}
+
+	for i, bounds := range handlers {
+		cl := clip.Rect(bounds).Push(ops)
+		key.InputOp{Tag: &handlers[i]}.Add(ops)
+		cl.Pop()
+	}
+	r.Frame(ops)
+
+	r.MoveFocus(FocusLeft)
+	assertFocus(t, r, &handlers[0])
+	r.MoveFocus(FocusLeft)
+	assertFocus(t, r, &handlers[0])
+	r.MoveFocus(FocusRight)
+	assertFocus(t, r, &handlers[1])
+	r.MoveFocus(FocusRight)
+	assertFocus(t, r, &handlers[1])
+	r.MoveFocus(FocusDown)
+	assertFocus(t, r, &handlers[2])
+	r.MoveFocus(FocusDown)
+	assertFocus(t, r, &handlers[2])
+	r.MoveFocus(FocusLeft)
+	assertFocus(t, r, &handlers[3])
+	r.MoveFocus(FocusUp)
+	assertFocus(t, r, &handlers[0])
+
+	r.MoveFocus(FocusForward)
+	assertFocus(t, r, &handlers[1])
+	r.MoveFocus(FocusBackward)
+	assertFocus(t, r, &handlers[0])
+}
+
+func TestFocusScroll(t *testing.T) {
+	ops := new(op.Ops)
+	r := new(Router)
+	h := new(int)
+
+	parent := clip.Rect(image.Rect(1, 1, 14, 39)).Push(ops)
+	cl := clip.Rect(image.Rect(10, -20, 20, 30)).Push(ops)
+	key.InputOp{Tag: h}.Add(ops)
+	pointer.InputOp{
+		Tag:          h,
+		Kinds:        pointer.Scroll,
+		ScrollBounds: image.Rect(-100, -100, 100, 100),
+	}.Add(ops)
+	// Test that h is scrolled even if behind another handler.
+	pointer.InputOp{
+		Tag: new(int),
+	}.Add(ops)
+	cl.Pop()
+	parent.Pop()
+	r.Frame(ops)
+
+	r.MoveFocus(FocusLeft)
+	r.RevealFocus(image.Rect(0, 0, 15, 40))
+	evts := r.Events(h)
+	assertScrollEvent(t, evts[len(evts)-1], f32.Pt(6, -9))
+}
+
+func TestFocusClick(t *testing.T) {
+	ops := new(op.Ops)
+	r := new(Router)
+	h := new(int)
+
+	cl := clip.Rect(image.Rect(0, 0, 10, 10)).Push(ops)
+	key.InputOp{Tag: h}.Add(ops)
+	pointer.InputOp{
+		Tag:   h,
+		Kinds: pointer.Press | pointer.Release,
+	}.Add(ops)
+	cl.Pop()
+	r.Frame(ops)
+
+	r.MoveFocus(FocusLeft)
+	r.ClickFocus()
+	assertEventPointerTypeSequence(t, r.Events(h), pointer.Cancel, pointer.Press, pointer.Release)
+}
+
+func TestNoFocus(t *testing.T) {
+	r := new(Router)
+	r.MoveFocus(FocusForward)
+}
+
+func TestKeyRouting(t *testing.T) {
+	handlers := make([]int, 5)
+	ops := new(op.Ops)
+	macroOps := new(op.Ops)
+	r := new(Router)
+
+	rect := clip.Rect{Max: image.Pt(10, 10)}
+
+	macro := op.Record(macroOps)
+	key.InputOp{Tag: &handlers[0], Keys: "A"}.Add(ops)
+	cl1 := rect.Push(ops)
+	key.InputOp{Tag: &handlers[1], Keys: "B"}.Add(ops)
+	key.InputOp{Tag: &handlers[2], Keys: "A"}.Add(ops)
+	cl1.Pop()
+	cl2 := rect.Push(ops)
+	key.InputOp{Tag: &handlers[3]}.Add(ops)
+	key.InputOp{Tag: &handlers[4], Keys: "A"}.Add(ops)
+	cl2.Pop()
+	call := macro.Stop()
+	call.Add(ops)
+
+	r.Frame(ops)
+
+	A, B := key.Event{Name: "A"}, key.Event{Name: "B"}
+	r.Queue(A, B)
+
+	// With no focus, the events should traverse the final branch of the hit tree
+	// searching for handlers.
+	assertKeyEvent(t, r.Events(&handlers[4]), false, A)
+	assertKeyEvent(t, r.Events(&handlers[3]), false)
+	assertKeyEvent(t, r.Events(&handlers[2]), false)
+	assertKeyEvent(t, r.Events(&handlers[1]), false, B)
+	assertKeyEvent(t, r.Events(&handlers[0]), false)
+
+	r2 := new(Router)
+
+	call.Add(ops)
+	key.FocusOp{Tag: &handlers[3]}.Add(ops)
+	r2.Frame(ops)
+
+	r2.Queue(A, B)
+
+	// With focus, the events should traverse the branch of the hit tree
+	// containing the focused element.
+	assertKeyEvent(t, r2.Events(&handlers[4]), false)
+	assertKeyEvent(t, r2.Events(&handlers[3]), true)
+	assertKeyEvent(t, r2.Events(&handlers[2]), false)
+	assertKeyEvent(t, r2.Events(&handlers[1]), false)
+	assertKeyEvent(t, r2.Events(&handlers[0]), false, A)
+}
+
+func assertKeyEvent(t *testing.T, events []event.Event, expectedFocus bool, expectedInputs ...event.Event) {
+	t.Helper()
+	var evtFocus int
+	var evtKeyPress int
+	for _, e := range events {
+		switch ev := e.(type) {
+		case key.FocusEvent:
+			if ev.Focus != expectedFocus {
+				t.Errorf("focus is expected to be %v, got %v", expectedFocus, ev.Focus)
+			}
+			evtFocus++
+		case key.Event, key.EditEvent:
+			if len(expectedInputs) <= evtKeyPress {
+				t.Fatalf("unexpected key events")
+			}
+			if !reflect.DeepEqual(ev, expectedInputs[evtKeyPress]) {
+				t.Errorf("expected %v events, got %v", expectedInputs[evtKeyPress], ev)
+			}
+			evtKeyPress++
+		}
+	}
+	if evtFocus <= 0 {
+		t.Errorf("expected focus event")
+	}
+	if evtFocus > 1 {
+		t.Errorf("expected single focus event")
+	}
+	if evtKeyPress != len(expectedInputs) {
+		t.Errorf("expected key events")
+	}
+}
+
+func assertKeyEventUnexpected(t *testing.T, events []event.Event) {
+	t.Helper()
+	var evtFocus int
+	for _, e := range events {
+		switch e.(type) {
+		case key.FocusEvent:
+			evtFocus++
+		}
+	}
+	if evtFocus > 1 {
+		t.Errorf("unexpected focus event")
+	}
+}
+
+func assertFocus(t *testing.T, router *Router, expected event.Tag) {
+	t.Helper()
+	if got := router.key.queue.focus; got != expected {
+		t.Errorf("expected %v to be focused, got %v", expected, got)
+	}
+}
+
+func assertKeyboard(t *testing.T, router *Router, expected TextInputState) {
+	t.Helper()
+	if got := router.key.queue.state; got != expected {
+		t.Errorf("expected %v keyboard, got %v", expected, got)
+	}
+}

io/router/pointer.go

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: Unlicense OR MIT
 
-package input
+package router
 
 import (
 	"image"
@@ -10,6 +10,7 @@ import (
 	f32internal "gioui.org/internal/f32"
 	"gioui.org/internal/ops"
 	"gioui.org/io/event"
+	"gioui.org/io/key"
 	"gioui.org/io/pointer"
 	"gioui.org/io/semantic"
 	"gioui.org/io/system"
@@ -17,8 +18,14 @@ import (
 )
 
 type pointerQueue struct {
-	hitTree []hitNode
+	hitTree   []hitNode
-	areas   []areaNode
+	areas     []areaNode
+	cursor    pointer.Cursor
+	handlers  map[event.Tag]*pointerHandler
+	pointers  []pointerInfo
+	transfers []io.ReadCloser // pending data transfers
+
+	scratch []event.Tag
 
 	semantic struct {
 		idsAssigned bool
@@ -36,15 +43,10 @@ type hitNode struct {
 
 	// For handler nodes.
 	tag  event.Tag
+	ktag event.Tag
 	pass bool
 }
 
-// pointerState is the input state related to pointer events.
-type pointerState struct {
-	cursor   pointer.Cursor
-	pointers []pointerInfo
-}
-
 type pointerInfo struct {
 	id       pointer.ID
 	pressed  bool
@@ -61,21 +63,17 @@ type pointerInfo struct {
 }
 
 type pointerHandler struct {
-	// areaPlusOne is the index into the list of pointerQueue.areas, plus 1.
+	area      int
-	areaPlusOne int
+	active    bool
-	// setup tracks whether the handler has received
+	wantsGrab bool
-	// the pointer.Cancel event that resets its state.
+	types     pointer.Kind
-	setup bool
-}
-
-// pointerFilter represents the union of a set of pointer filters.
-type pointerFilter struct {
-	kinds pointer.Kind
 	// min and max horizontal/vertical scroll
 	scrollRange image.Rectangle
 
 	sourceMimes []string
 	targetMimes []string
+	offeredMime string
+	data        io.ReadCloser
 }
 
 type areaOp struct {
@@ -231,18 +229,33 @@ func (c *pointerCollector) addHitNode(n hitNode) {
 }
 
 // newHandler returns the current handler or a new one for tag.
-func (c *pointerCollector) newHandler(tag event.Tag, state *pointerHandler) {
+func (c *pointerCollector) newHandler(tag event.Tag, events *handlerEvents) *pointerHandler {
 	areaID := c.currentArea()
 	c.addHitNode(hitNode{
 		area: areaID,
 		tag:  tag,
 		pass: c.state.pass > 0,
 	})
-	state.areaPlusOne = areaID + 1
+	h, ok := c.q.handlers[tag]
+	if !ok {
+		h = new(pointerHandler)
+		c.q.handlers[tag] = h
+		// Cancel handlers on (each) first appearance, but don't
+		// trigger redraw.
+		events.AddNoRedraw(tag, pointer.Event{Kind: pointer.Cancel})
+	}
+	h.active = true
+	h.area = areaID
+	return h
 }
 
-func (s *pointerHandler) Reset() {
+func (c *pointerCollector) keyInputOp(op key.InputOp) {
-	s.areaPlusOne = 0
+	areaID := c.currentArea()
+	c.addHitNode(hitNode{
+		area: areaID,
+		ktag: op.Tag,
+		pass: true,
+	})
 }
 
 func (c *pointerCollector) actionInputOp(act system.Action) {
@@ -251,109 +264,21 @@ func (c *pointerCollector) actionInputOp(act system.Action) {
 	area.action = act
 }
 
-func (q *pointerQueue) grab(state pointerState, req pointer.GrabCmd) (pointerState, []taggedEvent) {
+func (c *pointerCollector) inputOp(op pointer.InputOp, events *handlerEvents) {
-	var evts []taggedEvent
-	for _, p := range state.pointers {
-		if !p.pressed || p.id != req.ID {
-			continue
-		}
-		// Drop other handlers that lost their grab.
-		for i := len(p.handlers) - 1; i >= 0; i-- {
-			if tag := p.handlers[i]; tag != req.Tag {
-				evts = append(evts, taggedEvent{
-					tag:   tag,
-					event: pointer.Event{Kind: pointer.Cancel},
-				})
-				state = dropHandler(state, tag)
-			}
-		}
-		break
-	}
-	return state, evts
-}
-
-func (c *pointerCollector) inputOp(tag event.Tag, state *pointerHandler) {
 	areaID := c.currentArea()
 	area := &c.q.areas[areaID]
-	area.semantic.content.tag = tag
+	area.semantic.content.tag = op.Tag
-	c.newHandler(tag, state)
+	if op.Kinds&(pointer.Press|pointer.Release) != 0 {
-}
+		area.semantic.content.gestures |= ClickGesture
-
-func (p *pointerFilter) Add(f event.Filter) {
-	switch f := f.(type) {
-	case transfer.SourceFilter:
-		for _, m := range p.sourceMimes {
-			if m == f.Type {
-				return
-			}
-		}
-		p.sourceMimes = append(p.sourceMimes, f.Type)
-	case transfer.TargetFilter:
-		for _, m := range p.targetMimes {
-			if m == f.Type {
-				return
-			}
-		}
-		p.targetMimes = append(p.targetMimes, f.Type)
-	case pointer.Filter:
-		p.kinds = p.kinds | f.Kinds
-		p.scrollRange = p.scrollRange.Union(f.ScrollBounds)
 	}
-}
+	if op.Kinds&pointer.Scroll != 0 {
-
+		area.semantic.content.gestures |= ScrollGesture
-func (p *pointerFilter) Matches(e event.Event) bool {
-	switch e := e.(type) {
-	case pointer.Event:
-		return e.Kind&p.kinds == e.Kind
-	case transfer.CancelEvent, transfer.InitiateEvent:
-		return len(p.sourceMimes) > 0 || len(p.targetMimes) > 0
-	case transfer.RequestEvent:
-		for _, t := range p.sourceMimes {
-			if t == e.Type {
-				return true
-			}
-		}
-	case transfer.DataEvent:
-		for _, t := range p.targetMimes {
-			if t == e.Type {
-				return true
-			}
-		}
 	}
-	return false
+	area.semantic.valid = area.semantic.content.gestures != 0
-}
+	h := c.newHandler(op.Tag, events)
-
+	h.wantsGrab = h.wantsGrab || op.Grab
-func (p *pointerFilter) Merge(p2 pointerFilter) {
+	h.types = h.types | op.Kinds
-	p.kinds = p.kinds | p2.kinds
+	h.scrollRange = op.ScrollBounds
-	p.scrollRange = p.scrollRange.Union(p2.scrollRange)
-	p.sourceMimes = append(p.sourceMimes, p2.sourceMimes...)
-	p.targetMimes = append(p.targetMimes, p2.targetMimes...)
-}
-
-// clampScroll splits a scroll distance in the remaining scroll and the
-// scroll accepted by the filter.
-func (p *pointerFilter) clampScroll(scroll f32.Point) (left, scrolled f32.Point) {
-	left.X, scrolled.X = clampSplit(scroll.X, p.scrollRange.Min.X, p.scrollRange.Max.X)
-	left.Y, scrolled.Y = clampSplit(scroll.Y, p.scrollRange.Min.Y, p.scrollRange.Max.Y)
-	return
-}
-
-func clampSplit(v float32, min, max int) (float32, float32) {
-	if m := float32(max); v > m {
-		return v - m, m
-	}
-	if m := float32(min); v < m {
-		return v - m, m
-	}
-	return 0, v
-}
-
-func (s *pointerHandler) ResetEvent() (event.Event, bool) {
-	if s.setup {
-		return nil, false
-	}
-	s.setup = true
-	return pointer.Event{Kind: pointer.Cancel}, true
 }
 
 func (c *pointerCollector) semanticLabel(lbl string) {
@@ -397,28 +322,23 @@ func (c *pointerCollector) cursor(cursor pointer.Cursor) {
 	area.cursor = cursor
 }
 
-func (q *pointerQueue) offerData(handlers map[event.Tag]*handler, state pointerState, req transfer.OfferCmd) (pointerState, []taggedEvent) {
+func (c *pointerCollector) sourceOp(op transfer.SourceOp, events *handlerEvents) {
-	var evts []taggedEvent
+	h := c.newHandler(op.Tag, events)
-	for i, p := range state.pointers {
+	h.sourceMimes = append(h.sourceMimes, op.Type)
-		if p.dataSource != req.Tag {
-			continue
-		}
-		if p.dataTarget != nil {
-			evts = append(evts, taggedEvent{tag: p.dataTarget, event: transfer.DataEvent{
-				Type: req.Type,
-				Open: func() io.ReadCloser {
-					return req.Data
-				},
-			}})
-		}
-		state.pointers = append([]pointerInfo{}, state.pointers...)
-		state.pointers[i], evts = q.deliverTransferCancelEvent(handlers, p, evts)
-		break
-	}
-	return state, evts
 }
 
-func (c *pointerCollector) Reset() {
+func (c *pointerCollector) targetOp(op transfer.TargetOp, events *handlerEvents) {
+	h := c.newHandler(op.Tag, events)
+	h.targetMimes = append(h.targetMimes, op.Type)
+}
+
+func (c *pointerCollector) offerOp(op transfer.OfferOp, events *handlerEvents) {
+	h := c.newHandler(op.Tag, events)
+	h.offeredMime = op.Type
+	h.data = op.Data
+}
+
+func (c *pointerCollector) reset() {
 	c.q.reset()
 	c.resetState()
 	c.ensureRoot()
@@ -573,6 +493,20 @@ func (q *pointerQueue) hitTest(pos f32.Point, onNode func(*hitNode) bool) pointe
 	return cursor
 }
 
+func (q *pointerQueue) opHit(pos f32.Point) ([]event.Tag, pointer.Cursor) {
+	hits := q.scratch[:0]
+	cursor := q.hitTest(pos, func(n *hitNode) bool {
+		if n.tag != nil {
+			if _, exists := q.handlers[n.tag]; exists {
+				hits = addHandler(hits, n.tag)
+			}
+		}
+		return true
+	})
+	q.scratch = hits[:0]
+	return hits, cursor
+}
+
 func (q *pointerQueue) invTransform(areaIdx int, p f32.Point) f32.Point {
 	if areaIdx == -1 {
 		return p
@@ -597,6 +531,17 @@ func (q *pointerQueue) hit(areaIdx int, p f32.Point) (bool, pointer.Cursor) {
 }
 
 func (q *pointerQueue) reset() {
+	if q.handlers == nil {
+		q.handlers = make(map[event.Tag]*pointerHandler)
+	}
+	for _, h := range q.handlers {
+		// Reset handler.
+		h.active = false
+		h.wantsGrab = false
+		h.types = 0
+		h.sourceMimes = h.sourceMimes[:0]
+		h.targetMimes = h.targetMimes[:0]
+	}
 	q.hitTree = q.hitTree[:0]
 	q.areas = q.areas[:0]
 	q.semantic.idsAssigned = false
@@ -614,71 +559,80 @@ func (q *pointerQueue) reset() {
 			delete(q.semantic.contentIDs, k)
 		}
 	}
+	for _, rc := range q.transfers {
+		if rc != nil {
+			rc.Close()
+		}
+	}
+	q.transfers = nil
 }
 
-func (q *pointerQueue) Frame(handlers map[event.Tag]*handler, state pointerState) (pointerState, []taggedEvent) {
+func (q *pointerQueue) Frame(events *handlerEvents) {
-	for _, h := range handlers {
+	for k, h := range q.handlers {
-		if h.pointer.areaPlusOne != 0 {
+		if !h.active {
-			area := &q.areas[h.pointer.areaPlusOne-1]
+			q.dropHandler(nil, k)
-			if h.filter.pointer.kinds&(pointer.Press|pointer.Release) != 0 {
+			delete(q.handlers, k)
-				area.semantic.content.gestures |= ClickGesture
+		}
+		if h.wantsGrab {
+			for _, p := range q.pointers {
+				if !p.pressed {
+					continue
+				}
+				for i, k2 := range p.handlers {
+					if k2 == k {
+						// Drop other handlers that lost their grab.
+						dropped := q.scratch[:0]
+						dropped = append(dropped, p.handlers[:i]...)
+						dropped = append(dropped, p.handlers[i+1:]...)
+						for _, tag := range dropped {
+							q.dropHandler(events, tag)
+						}
+						break
+					}
+				}
 			}
-			if h.filter.pointer.kinds&pointer.Scroll != 0 {
-				area.semantic.content.gestures |= ScrollGesture
-			}
-			area.semantic.valid = area.semantic.content.gestures != 0
 		}
 	}
-	var evts []taggedEvent
+	for i := range q.pointers {
-	for i, p := range state.pointers {
+		p := &q.pointers[i]
-		changed := false
+		q.deliverEnterLeaveEvents(p, events, p.last)
-		p, evts, state.cursor, changed = q.deliverEnterLeaveEvents(handlers, state.cursor, p, evts, p.last)
+		q.deliverTransferDataEvent(p, events)
-		if changed {
-			state.pointers = append([]pointerInfo{}, state.pointers...)
-			state.pointers[i] = p
-		}
 	}
-	return state, evts
 }
 
-func dropHandler(state pointerState, tag event.Tag) pointerState {
+func (q *pointerQueue) dropHandler(events *handlerEvents, tag event.Tag) {
-	pointers := state.pointers
+	if events != nil {
-	state.pointers = nil
+		events.Add(tag, pointer.Event{Kind: pointer.Cancel})
-	for _, p := range pointers {
+	}
-		handlers := p.handlers
+	for i := range q.pointers {
-		p.handlers = nil
+		p := &q.pointers[i]
-		for _, h := range handlers {
+		for i := len(p.handlers) - 1; i >= 0; i-- {
-			if h != tag {
+			if p.handlers[i] == tag {
-				p.handlers = append(p.handlers, h)
+				p.handlers = append(p.handlers[:i], p.handlers[i+1:]...)
-			}
+			}
-		}
+		}
-		entered := p.entered
+		for i := len(p.entered) - 1; i >= 0; i-- {
-		p.entered = nil
+			if p.entered[i] == tag {
-		for _, h := range entered {
+				p.entered = append(p.entered[:i], p.entered[i+1:]...)
-			if h != tag {
+			}
-				p.entered = append(p.entered, h)
+		}
-			}
-		}
-		state.pointers = append(state.pointers, p)
 	}
-	return state
 }
 
 // pointerOf returns the pointerInfo index corresponding to the pointer in e.
-func (s pointerState) pointerOf(e pointer.Event) (pointerState, int) {
+func (q *pointerQueue) pointerOf(e pointer.Event) int {
-	for i, p := range s.pointers {
+	for i, p := range q.pointers {
 		if p.id == e.PointerID {
-			return s, i
+			return i
 		}
 	}
-	n := len(s.pointers)
+	q.pointers = append(q.pointers, pointerInfo{id: e.PointerID})
-	s.pointers = append(s.pointers[:n:n], pointerInfo{id: e.PointerID})
+	return len(q.pointers) - 1
-	return s, len(s.pointers) - 1
 }
 
 // Deliver is like Push, but delivers an event to a particular area.
-func (q *pointerQueue) Deliver(handlers map[event.Tag]*handler, areaIdx int, e pointer.Event) []taggedEvent {
+func (q *pointerQueue) Deliver(areaIdx int, e pointer.Event, events *handlerEvents) {
-	scroll := e.Scroll
+	var sx, sy = e.Scroll.X, e.Scroll.Y
 	idx := len(q.hitTree) - 1
 	// Locate first potential receiver.
 	for idx != -1 {
@@ -688,28 +642,31 @@ func (q *pointerQueue) Deliver(handlers map[event.Tag]*handler, areaIdx int, e p
 		}
 		idx--
 	}
-	var evts []taggedEvent
 	for idx != -1 {
 		n := &q.hitTree[idx]
 		idx = n.next
-		h, ok := handlers[n.tag]
+		if n.tag == nil {
-		if !ok || !h.filter.pointer.Matches(e) {
+			continue
+		}
+		h := q.handlers[n.tag]
+		if e.Kind&h.types == 0 {
 			continue
 		}
 		e := e
 		if e.Kind == pointer.Scroll {
-			if scroll == (f32.Point{}) {
+			if sx == 0 && sy == 0 {
 				break
 			}
-			scroll, e.Scroll = h.filter.pointer.clampScroll(scroll)
+			// Distribute the scroll to the handler based on its ScrollRange.
+			sx, e.Scroll.X = setScrollEvent(sx, h.scrollRange.Min.X, h.scrollRange.Max.X)
+			sy, e.Scroll.Y = setScrollEvent(sy, h.scrollRange.Min.Y, h.scrollRange.Max.Y)
 		}
-		e.Position = q.invTransform(h.pointer.areaPlusOne-1, e.Position)
+		e.Position = q.invTransform(h.area, e.Position)
-		evts = append(evts, taggedEvent{tag: n.tag, event: e})
+		events.Add(n.tag, e)
 		if e.Kind != pointer.Scroll {
 			break
 		}
 	}
-	return evts
 }
 
 // SemanticArea returns the sematic content for area, and its parent area.
@@ -725,129 +682,106 @@ func (q *pointerQueue) SemanticArea(areaIdx int) (semanticContent, int) {
 	return semanticContent{}, -1
 }
 
-func (q *pointerQueue) Push(handlers map[event.Tag]*handler, state pointerState, e pointer.Event) (pointerState, []taggedEvent) {
+func (q *pointerQueue) Push(e pointer.Event, events *handlerEvents) {
-	var evts []taggedEvent
 	if e.Kind == pointer.Cancel {
-		for k := range handlers {
+		q.pointers = q.pointers[:0]
-			evts = append(evts, taggedEvent{
+		for k := range q.handlers {
-				event: pointer.Event{Kind: pointer.Cancel},
+			q.dropHandler(events, k)
-				tag:   k,
-			})
 		}
-		state.pointers = nil
+		return
-		return state, evts
 	}
-	state, pidx := state.pointerOf(e)
+	pidx := q.pointerOf(e)
-	p := state.pointers[pidx]
+	p := &q.pointers[pidx]
+	p.last = e
 
 	switch e.Kind {
 	case pointer.Press:
-		p, evts, state.cursor, _ = q.deliverEnterLeaveEvents(handlers, state.cursor, p, evts, e)
+		q.deliverEnterLeaveEvents(p, events, e)
 		p.pressed = true
-		evts = q.deliverEvent(handlers, p, evts, e)
+		q.deliverEvent(p, events, e)
 	case pointer.Move:
 		if p.pressed {
 			e.Kind = pointer.Drag
 		}
-		p, evts, state.cursor, _ = q.deliverEnterLeaveEvents(handlers, state.cursor, p, evts, e)
+		q.deliverEnterLeaveEvents(p, events, e)
-		evts = q.deliverEvent(handlers, p, evts, e)
+		q.deliverEvent(p, events, e)
 		if p.pressed {
-			p, evts = q.deliverDragEvent(handlers, p, evts)
+			q.deliverDragEvent(p, events)
 		}
 	case pointer.Release:
-		evts = q.deliverEvent(handlers, p, evts, e)
+		q.deliverEvent(p, events, e)
 		p.pressed = false
-		p, evts, state.cursor, _ = q.deliverEnterLeaveEvents(handlers, state.cursor, p, evts, e)
+		q.deliverEnterLeaveEvents(p, events, e)
-		p, evts = q.deliverDropEvent(handlers, p, evts)
+		q.deliverDropEvent(p, events)
 	case pointer.Scroll:
-		p, evts, state.cursor, _ = q.deliverEnterLeaveEvents(handlers, state.cursor, p, evts, e)
+		q.deliverEnterLeaveEvents(p, events, e)
-		evts = q.deliverEvent(handlers, p, evts, e)
+		q.deliverEvent(p, events, e)
 	default:
 		panic("unsupported pointer event type")
 	}
 
-	p.last = e
-
 	if !p.pressed && len(p.entered) == 0 {
 		// No longer need to track pointer.
-		state.pointers = append(state.pointers[:pidx:pidx], state.pointers[pidx+1:]...)
+		q.pointers = append(q.pointers[:pidx], q.pointers[pidx+1:]...)
-	} else {
-		state.pointers = append([]pointerInfo{}, state.pointers...)
-		state.pointers[pidx] = p
 	}
-	return state, evts
 }
 
-func (q *pointerQueue) deliverEvent(handlers map[event.Tag]*handler, p pointerInfo, evts []taggedEvent, e pointer.Event) []taggedEvent {
+func (q *pointerQueue) deliverEvent(p *pointerInfo, events *handlerEvents, e pointer.Event) {
 	foremost := true
 	if p.pressed && len(p.handlers) == 1 {
 		e.Priority = pointer.Grabbed
 		foremost = false
 	}
-	scroll := e.Scroll
+	var sx, sy = e.Scroll.X, e.Scroll.Y
 	for _, k := range p.handlers {
-		h, ok := handlers[k]
+		h := q.handlers[k]
-		if !ok {
-			continue
-		}
-		f := h.filter.pointer
-		if !f.Matches(e) {
-			continue
-		}
 		if e.Kind == pointer.Scroll {
-			if scroll == (f32.Point{}) {
+			if sx == 0 && sy == 0 {
-				return evts
+				return
 			}
-			scroll, e.Scroll = f.clampScroll(scroll)
+			// Distribute the scroll to the handler based on its ScrollRange.
+			sx, e.Scroll.X = setScrollEvent(sx, h.scrollRange.Min.X, h.scrollRange.Max.X)
+			sy, e.Scroll.Y = setScrollEvent(sy, h.scrollRange.Min.Y, h.scrollRange.Max.Y)
+		}
+		if e.Kind&h.types == 0 {
+			continue
 		}
 		e := e
 		if foremost {
 			foremost = false
 			e.Priority = pointer.Foremost
 		}
-		e.Position = q.invTransform(h.pointer.areaPlusOne-1, e.Position)
+		e.Position = q.invTransform(h.area, e.Position)
-		evts = append(evts, taggedEvent{event: e, tag: k})
+		events.Add(k, e)
 	}
-	return evts
 }
 
-func (q *pointerQueue) deliverEnterLeaveEvents(handlers map[event.Tag]*handler, cursor pointer.Cursor, p pointerInfo, evts []taggedEvent, e pointer.Event) (pointerInfo, []taggedEvent, pointer.Cursor, bool) {
+func (q *pointerQueue) deliverEnterLeaveEvents(p *pointerInfo, events *handlerEvents, e pointer.Event) {
-	changed := false
 	var hits []event.Tag
 	if e.Source != pointer.Mouse && !p.pressed && e.Kind != pointer.Press {
 		// Consider non-mouse pointers leaving when they're released.
 	} else {
-		var transSrc *pointerFilter
+		hits, q.cursor = q.opHit(e.Position)
-		if p.dataSource != nil {
+		if p.pressed {
-			transSrc = &handlers[p.dataSource].filter.pointer
+			// Filter out non-participating handlers,
-		}
+			// except potential transfer targets when a transfer has been initiated.
-		cursor = q.hitTest(e.Position, func(n *hitNode) bool {
+			var hitsHaveTarget bool
-			h, ok := handlers[n.tag]
+			if p.dataSource != nil {
-			if !ok {
+				transferSource := q.handlers[p.dataSource]
-				return true
+				for _, hit := range hits {
-			}
+					if _, ok := firstMimeMatch(transferSource, q.handlers[hit]); ok {
-			add := true
+						hitsHaveTarget = true
-			if p.pressed {
+						break
-				add = false
-				// Filter out non-participating handlers,
-				// except potential transfer targets when a transfer has been initiated.
-				if _, found := searchTag(p.handlers, n.tag); found {
-					add = true
-				}
-				if transSrc != nil {
-					if _, ok := firstMimeMatch(transSrc, &h.filter.pointer); ok {
-						add = true
 					}
 				}
 			}
-			if add {
+			for i := len(hits) - 1; i >= 0; i-- {
-				hits = addHandler(hits, n.tag)
+				if _, found := searchTag(p.handlers, hits[i]); !found && !hitsHaveTarget {
+					hits = append(hits[:i], hits[i+1:]...)
+				}
 			}
-			return true
+		} else {
-		})
+			p.handlers = append(p.handlers[:0], hits...)
-		if !p.pressed {
-			changed = true
-			p.handlers = hits
 		}
 	}
 	// Deliver Leave events.
@@ -855,94 +789,111 @@ func (q *pointerQueue) deliverEnterLeaveEvents(handlers map[event.Tag]*handler,
 		if _, found := searchTag(hits, k); found {
 			continue
 		}
-		h, ok := handlers[k]
+		h := q.handlers[k]
-		if !ok {
-			continue
-		}
-		changed = true
-		e := e
 		e.Kind = pointer.Leave
 
-		if h.filter.pointer.Matches(e) {
+		if e.Kind&h.types != 0 {
-			e.Position = q.invTransform(h.pointer.areaPlusOne-1, e.Position)
+			e := e
-			evts = append(evts, taggedEvent{tag: k, event: e})
+			e.Position = q.invTransform(h.area, e.Position)
+			events.Add(k, e)
 		}
 	}
 	// Deliver Enter events.
 	for _, k := range hits {
+		h := q.handlers[k]
 		if _, found := searchTag(p.entered, k); found {
 			continue
 		}
-		h, ok := handlers[k]
-		if !ok {
-			continue
-		}
-		changed = true
-		e := e
 		e.Kind = pointer.Enter
 
-		if h.filter.pointer.Matches(e) {
+		if e.Kind&h.types != 0 {
-			e.Position = q.invTransform(h.pointer.areaPlusOne-1, e.Position)
+			e := e
-			evts = append(evts, taggedEvent{tag: k, event: e})
+			e.Position = q.invTransform(h.area, e.Position)
+			events.Add(k, e)
 		}
 	}
-	p.entered = hits
+	p.entered = append(p.entered[:0], hits...)
-	return p, evts, cursor, changed
 }
 
-func (q *pointerQueue) deliverDragEvent(handlers map[event.Tag]*handler, p pointerInfo, evts []taggedEvent) (pointerInfo, []taggedEvent) {
+func (q *pointerQueue) deliverDragEvent(p *pointerInfo, events *handlerEvents) {
 	if p.dataSource != nil {
-		return p, evts
+		return
 	}
 	// Identify the data source.
 	for _, k := range p.entered {
-		src := &handlers[k].filter.pointer
+		src := q.handlers[k]
 		if len(src.sourceMimes) == 0 {
 			continue
 		}
 		// One data source handler per pointer.
 		p.dataSource = k
 		// Notify all potential targets.
-		for k, tgt := range handlers {
+		for k, tgt := range q.handlers {
-			if _, ok := firstMimeMatch(src, &tgt.filter.pointer); ok {
+			if _, ok := firstMimeMatch(src, tgt); ok {
-				evts = append(evts, taggedEvent{tag: k, event: transfer.InitiateEvent{}})
+				events.Add(k, transfer.InitiateEvent{})
 			}
 		}
 		break
 	}
-	return p, evts
 }
 
-func (q *pointerQueue) deliverDropEvent(handlers map[event.Tag]*handler, p pointerInfo, evts []taggedEvent) (pointerInfo, []taggedEvent) {
+func (q *pointerQueue) deliverDropEvent(p *pointerInfo, events *handlerEvents) {
 	if p.dataSource == nil {
-		return p, evts
+		return
 	}
 	// Request data from the source.
-	src := &handlers[p.dataSource].filter.pointer
+	src := q.handlers[p.dataSource]
 	for _, k := range p.entered {
-		h := handlers[k]
+		h := q.handlers[k]
-		if m, ok := firstMimeMatch(src, &h.filter.pointer); ok {
+		if m, ok := firstMimeMatch(src, h); ok {
 			p.dataTarget = k
-			evts = append(evts, taggedEvent{tag: p.dataSource, event: transfer.RequestEvent{Type: m}})
+			events.Add(p.dataSource, transfer.RequestEvent{Type: m})
-			return p, evts
+			return
 		}
 	}
 	// No valid target found, abort.
-	return q.deliverTransferCancelEvent(handlers, p, evts)
+	q.deliverTransferCancelEvent(p, events)
 }
 
-func (q *pointerQueue) deliverTransferCancelEvent(handlers map[event.Tag]*handler, p pointerInfo, evts []taggedEvent) (pointerInfo, []taggedEvent) {
+func (q *pointerQueue) deliverTransferDataEvent(p *pointerInfo, events *handlerEvents) {
-	evts = append(evts, taggedEvent{tag: p.dataSource, event: transfer.CancelEvent{}})
+	if p.dataSource == nil {
+		return
+	}
+	src := q.handlers[p.dataSource]
+	if src.data == nil {
+		// Data not received yet.
+		return
+	}
+	if p.dataTarget == nil {
+		q.deliverTransferCancelEvent(p, events)
+		return
+	}
+	// Send the offered data to the target.
+	transferIdx := len(q.transfers)
+	events.Add(p.dataTarget, transfer.DataEvent{
+		Type: src.offeredMime,
+		Open: func() io.ReadCloser {
+			q.transfers[transferIdx] = nil
+			return src.data
+		},
+	})
+	q.transfers = append(q.transfers, src.data)
+	p.dataTarget = nil
+}
+
+func (q *pointerQueue) deliverTransferCancelEvent(p *pointerInfo, events *handlerEvents) {
+	events.Add(p.dataSource, transfer.CancelEvent{})
 	// Cancel all potential targets.
-	src := &handlers[p.dataSource].filter.pointer
+	src := q.handlers[p.dataSource]
-	for k, h := range handlers {
+	for k, h := range q.handlers {
-		if _, ok := firstMimeMatch(src, &h.filter.pointer); ok {
+		if _, ok := firstMimeMatch(src, h); ok {
-			evts = append(evts, taggedEvent{tag: k, event: transfer.CancelEvent{}})
+			events.Add(k, transfer.CancelEvent{})
 		}
 	}
+	src.offeredMime = ""
+	src.data = nil
 	p.dataSource = nil
 	p.dataTarget = nil
-	return p, evts
 }
 
 // ClipFor clips r to the parents of area.
@@ -977,7 +928,7 @@ func addHandler(tags []event.Tag, tag event.Tag) []event.Tag {
 }
 
 // firstMimeMatch returns the first type match between src and tgt.
-func firstMimeMatch(src, tgt *pointerFilter) (first string, matched bool) {
+func firstMimeMatch(src, tgt *pointerHandler) (first string, matched bool) {
 	for _, m1 := range tgt.targetMimes {
 		for _, m2 := range src.sourceMimes {
 			if m1 == m2 {
@@ -1014,3 +965,13 @@ func (a *areaNode) bounds() image.Rectangle {
 		Max: a.trans.Transform(f32internal.FPt(a.area.rect.Max)),
 	}.Round()
 }
+
+func setScrollEvent(scroll float32, min, max int) (left, scrolled float32) {
+	if v := float32(max); scroll > v {
+		return scroll - v, v
+	}
+	if v := float32(min); scroll < v {
+		return scroll - v, v
+	}
+	return 0, scroll
+}

io/router/router.go

@@ -0,0 +1,634 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+/*
+Package router implements Router, a event.Queue implementation
+that that disambiguates and routes events to handlers declared
+in operation lists.
+
+Router is used by app.Window and is otherwise only useful for
+using Gio with external window implementations.
+*/
+package router
+
+import (
+	"encoding/binary"
+	"image"
+	"io"
+	"math"
+	"strings"
+	"time"
+
+	"gioui.org/f32"
+	f32internal "gioui.org/internal/f32"
+	"gioui.org/internal/ops"
+	"gioui.org/io/clipboard"
+	"gioui.org/io/event"
+	"gioui.org/io/key"
+	"gioui.org/io/pointer"
+	"gioui.org/io/profile"
+	"gioui.org/io/semantic"
+	"gioui.org/io/system"
+	"gioui.org/io/transfer"
+	"gioui.org/op"
+)
+
+// Router is a Queue implementation that routes events
+// to handlers declared in operation lists.
+type Router struct {
+	savedTrans []f32.Affine2D
+	transStack []f32.Affine2D
+	pointer    struct {
+		queue     pointerQueue
+		collector pointerCollector
+	}
+	key struct {
+		queue     keyQueue
+		collector keyCollector
+	}
+	cqueue clipboardQueue
+
+	handlers handlerEvents
+
+	reader ops.Reader
+
+	// InvalidateOp summary.
+	wakeup     bool
+	wakeupTime time.Time
+
+	// ProfileOp summary.
+	profHandlers map[event.Tag]struct{}
+	profile      profile.Event
+}
+
+// SemanticNode represents a node in the tree describing the components
+// contained in a frame.
+type SemanticNode struct {
+	ID       SemanticID
+	ParentID SemanticID
+	Children []SemanticNode
+	Desc     SemanticDesc
+
+	areaIdx int
+}
+
+// SemanticDesc provides a semantic description of a UI component.
+type SemanticDesc struct {
+	Class       semantic.ClassOp
+	Description string
+	Label       string
+	Selected    bool
+	Disabled    bool
+	Gestures    SemanticGestures
+	Bounds      image.Rectangle
+}
+
+// SemanticGestures is a bit-set of supported gestures.
+type SemanticGestures int
+
+const (
+	ClickGesture SemanticGestures = 1 << iota
+	ScrollGesture
+)
+
+// SemanticID uniquely identifies a SemanticDescription.
+//
+// By convention, the zero value denotes the non-existent ID.
+type SemanticID uint64
+
+type handlerEvents struct {
+	handlers  map[event.Tag][]event.Event
+	hadEvents bool
+}
+
+// Events returns the available events for the handler key.
+func (q *Router) Events(k event.Tag) []event.Event {
+	events := q.handlers.Events(k)
+	if _, isprof := q.profHandlers[k]; isprof {
+		delete(q.profHandlers, k)
+		events = append(events, q.profile)
+	}
+	return events
+}
+
+// Frame replaces the declared handlers from the supplied
+// operation list. The text input state, wakeup time and whether
+// there are active profile handlers is also saved.
+func (q *Router) Frame(frame *op.Ops) {
+	q.handlers.Clear()
+	q.wakeup = false
+	for k := range q.profHandlers {
+		delete(q.profHandlers, k)
+	}
+	var ops *ops.Ops
+	if frame != nil {
+		ops = &frame.Internal
+	}
+	q.reader.Reset(ops)
+	q.collect()
+
+	q.pointer.queue.Frame(&q.handlers)
+	q.key.queue.Frame(&q.handlers, q.key.collector)
+	if q.handlers.HadEvents() {
+		q.wakeup = true
+		q.wakeupTime = time.Time{}
+	}
+}
+
+// Queue key events to the topmost handler.
+func (q *Router) QueueTopmost(events ...key.Event) bool {
+	var topmost event.Tag
+	pq := &q.pointer.queue
+	for _, h := range pq.hitTree {
+		if h.ktag != nil {
+			topmost = h.ktag
+			break
+		}
+	}
+	if topmost == nil {
+		return false
+	}
+	for _, e := range events {
+		q.handlers.Add(topmost, e)
+	}
+	return q.handlers.HadEvents()
+}
+
+// Queue events and report whether at least one handler had an event queued.
+func (q *Router) Queue(events ...event.Event) bool {
+	for _, e := range events {
+		switch e := e.(type) {
+		case profile.Event:
+			q.profile = e
+		case pointer.Event:
+			q.pointer.queue.Push(e, &q.handlers)
+		case key.Event:
+			q.queueKeyEvent(e)
+		case key.SnippetEvent:
+			// Expand existing, overlapping snippet.
+			if r := q.key.queue.content.Snippet.Range; rangeOverlaps(r, key.Range(e)) {
+				if e.Start > r.Start {
+					e.Start = r.Start
+				}
+				if e.End < r.End {
+					e.End = r.End
+				}
+			}
+			if f := q.key.queue.focus; f != nil {
+				q.handlers.Add(f, e)
+			}
+		case key.EditEvent, key.FocusEvent, key.SelectionEvent:
+			if f := q.key.queue.focus; f != nil {
+				q.handlers.Add(f, e)
+			}
+		case clipboard.Event:
+			q.cqueue.Push(e, &q.handlers)
+		}
+	}
+	return q.handlers.HadEvents()
+}
+
+func rangeOverlaps(r1, r2 key.Range) bool {
+	r1 = rangeNorm(r1)
+	r2 = rangeNorm(r2)
+	return r1.Start <= r2.Start && r2.Start < r1.End ||
+		r1.Start <= r2.End && r2.End < r1.End
+}
+
+func rangeNorm(r key.Range) key.Range {
+	if r.End < r.Start {
+		r.End, r.Start = r.Start, r.End
+	}
+	return r
+}
+
+func (q *Router) queueKeyEvent(e key.Event) {
+	kq := &q.key.queue
+	f := q.key.queue.focus
+	if f != nil && kq.Accepts(f, e) {
+		q.handlers.Add(f, e)
+		return
+	}
+	pq := &q.pointer.queue
+	idx := len(pq.hitTree) - 1
+	focused := f != nil
+	if focused {
+		// If there is a focused tag, traverse its ancestry through the
+		// hit tree to search for handlers.
+		for ; pq.hitTree[idx].ktag != f; idx-- {
+		}
+	}
+	for idx != -1 {
+		n := &pq.hitTree[idx]
+		if focused {
+			idx = n.next
+		} else {
+			idx--
+		}
+		if n.ktag == nil {
+			continue
+		}
+		if kq.Accepts(n.ktag, e) {
+			q.handlers.Add(n.ktag, e)
+			break
+		}
+	}
+}
+
+func (q *Router) MoveFocus(dir FocusDirection) bool {
+	return q.key.queue.MoveFocus(dir, &q.handlers)
+}
+
+// RevealFocus scrolls the current focus (if any) into viewport
+// if there are scrollable parent handlers.
+func (q *Router) RevealFocus(viewport image.Rectangle) {
+	focus := q.key.queue.focus
+	if focus == nil {
+		return
+	}
+	bounds := q.key.queue.BoundsFor(focus)
+	area := q.key.queue.AreaFor(focus)
+	viewport = q.pointer.queue.ClipFor(area, viewport)
+
+	topleft := bounds.Min.Sub(viewport.Min)
+	topleft = max(topleft, bounds.Max.Sub(viewport.Max))
+	topleft = min(image.Pt(0, 0), topleft)
+	bottomright := bounds.Max.Sub(viewport.Max)
+	bottomright = min(bottomright, bounds.Min.Sub(viewport.Min))
+	bottomright = max(image.Pt(0, 0), bottomright)
+	s := topleft
+	if s.X == 0 {
+		s.X = bottomright.X
+	}
+	if s.Y == 0 {
+		s.Y = bottomright.Y
+	}
+	q.ScrollFocus(s)
+}
+
+// ScrollFocus scrolls the focused widget, if any, by dist.
+func (q *Router) ScrollFocus(dist image.Point) {
+	focus := q.key.queue.focus
+	if focus == nil {
+		return
+	}
+	area := q.key.queue.AreaFor(focus)
+	q.pointer.queue.Deliver(area, pointer.Event{
+		Kind:   pointer.Scroll,
+		Source: pointer.Touch,
+		Scroll: f32internal.FPt(dist),
+	}, &q.handlers)
+}
+
+func max(p1, p2 image.Point) image.Point {
+	m := p1
+	if p2.X > m.X {
+		m.X = p2.X
+	}
+	if p2.Y > m.Y {
+		m.Y = p2.Y
+	}
+	return m
+}
+
+func min(p1, p2 image.Point) image.Point {
+	m := p1
+	if p2.X < m.X {
+		m.X = p2.X
+	}
+	if p2.Y < m.Y {
+		m.Y = p2.Y
+	}
+	return m
+}
+
+func (q *Router) ActionAt(p f32.Point) (system.Action, bool) {
+	return q.pointer.queue.ActionAt(p)
+}
+
+func (q *Router) ClickFocus() {
+	focus := q.key.queue.focus
+	if focus == nil {
+		return
+	}
+	bounds := q.key.queue.BoundsFor(focus)
+	center := bounds.Max.Add(bounds.Min).Div(2)
+	e := pointer.Event{
+		Position: f32.Pt(float32(center.X), float32(center.Y)),
+		Source:   pointer.Touch,
+	}
+	area := q.key.queue.AreaFor(focus)
+	e.Kind = pointer.Press
+	q.pointer.queue.Deliver(area, e, &q.handlers)
+	e.Kind = pointer.Release
+	q.pointer.queue.Deliver(area, e, &q.handlers)
+}
+
+// TextInputState returns the input state from the most recent
+// call to Frame.
+func (q *Router) TextInputState() TextInputState {
+	return q.key.queue.InputState()
+}
+
+// TextInputHint returns the input mode from the most recent key.InputOp.
+func (q *Router) TextInputHint() (key.InputHint, bool) {
+	return q.key.queue.InputHint()
+}
+
+// WriteClipboard returns the most recent text to be copied
+// to the clipboard, if any.
+func (q *Router) WriteClipboard() (string, bool) {
+	return q.cqueue.WriteClipboard()
+}
+
+// ReadClipboard reports if any new handler is waiting
+// to read the clipboard.
+func (q *Router) ReadClipboard() bool {
+	return q.cqueue.ReadClipboard()
+}
+
+// Cursor returns the last cursor set.
+func (q *Router) Cursor() pointer.Cursor {
+	return q.pointer.queue.cursor
+}
+
+// SemanticAt returns the first semantic description under pos, if any.
+func (q *Router) SemanticAt(pos f32.Point) (SemanticID, bool) {
+	return q.pointer.queue.SemanticAt(pos)
+}
+
+// AppendSemantics appends the semantic tree to nodes, and returns the result.
+// The root node is the first added.
+func (q *Router) AppendSemantics(nodes []SemanticNode) []SemanticNode {
+	q.pointer.collector.q = &q.pointer.queue
+	q.pointer.collector.ensureRoot()
+	return q.pointer.queue.AppendSemantics(nodes)
+}
+
+// EditorState returns the editor state for the focused handler, or the
+// zero value if there is none.
+func (q *Router) EditorState() EditorState {
+	return q.key.queue.content
+}
+
+func (q *Router) collect() {
+	q.transStack = q.transStack[:0]
+	pc := &q.pointer.collector
+	pc.q = &q.pointer.queue
+	pc.reset()
+	kc := &q.key.collector
+	*kc = keyCollector{q: &q.key.queue}
+	q.key.queue.Reset()
+	var t f32.Affine2D
+	bo := binary.LittleEndian
+	for encOp, ok := q.reader.Decode(); ok; encOp, ok = q.reader.Decode() {
+		switch ops.OpType(encOp.Data[0]) {
+		case ops.TypeInvalidate:
+			op := decodeInvalidateOp(encOp.Data)
+			if !q.wakeup || op.At.Before(q.wakeupTime) {
+				q.wakeup = true
+				q.wakeupTime = op.At
+			}
+		case ops.TypeProfile:
+			op := decodeProfileOp(encOp.Data, encOp.Refs)
+			if q.profHandlers == nil {
+				q.profHandlers = make(map[event.Tag]struct{})
+			}
+			q.profHandlers[op.Tag] = struct{}{}
+		case ops.TypeClipboardRead:
+			q.cqueue.ProcessReadClipboard(encOp.Refs)
+		case ops.TypeClipboardWrite:
+			q.cqueue.ProcessWriteClipboard(encOp.Refs)
+		case ops.TypeSave:
+			id := ops.DecodeSave(encOp.Data)
+			if extra := id - len(q.savedTrans) + 1; extra > 0 {
+				q.savedTrans = append(q.savedTrans, make([]f32.Affine2D, extra)...)
+			}
+			q.savedTrans[id] = t
+		case ops.TypeLoad:
+			id := ops.DecodeLoad(encOp.Data)
+			t = q.savedTrans[id]
+			pc.resetState()
+			pc.setTrans(t)
+
+		case ops.TypeClip:
+			var op ops.ClipOp
+			op.Decode(encOp.Data)
+			pc.clip(op)
+		case ops.TypePopClip:
+			pc.popArea()
+		case ops.TypeTransform:
+			t2, push := ops.DecodeTransform(encOp.Data)
+			if push {
+				q.transStack = append(q.transStack, t)
+			}
+			t = t.Mul(t2)
+			pc.setTrans(t)
+		case ops.TypePopTransform:
+			n := len(q.transStack)
+			t = q.transStack[n-1]
+			q.transStack = q.transStack[:n-1]
+			pc.setTrans(t)
+
+		// Pointer ops.
+		case ops.TypePass:
+			pc.pass()
+		case ops.TypePopPass:
+			pc.popPass()
+		case ops.TypePointerInput:
+			op := pointer.InputOp{
+				Tag:   encOp.Refs[0].(event.Tag),
+				Grab:  encOp.Data[1] != 0,
+				Kinds: pointer.Kind(bo.Uint16(encOp.Data[2:])),
+				ScrollBounds: image.Rectangle{
+					Min: image.Point{
+						X: int(int32(bo.Uint32(encOp.Data[4:]))),
+						Y: int(int32(bo.Uint32(encOp.Data[8:]))),
+					},
+					Max: image.Point{
+						X: int(int32(bo.Uint32(encOp.Data[12:]))),
+						Y: int(int32(bo.Uint32(encOp.Data[16:]))),
+					},
+				},
+			}
+			pc.inputOp(op, &q.handlers)
+		case ops.TypeCursor:
+			name := pointer.Cursor(encOp.Data[1])
+			pc.cursor(name)
+		case ops.TypeSource:
+			op := transfer.SourceOp{
+				Tag:  encOp.Refs[0].(event.Tag),
+				Type: encOp.Refs[1].(string),
+			}
+			pc.sourceOp(op, &q.handlers)
+		case ops.TypeTarget:
+			op := transfer.TargetOp{
+				Tag:  encOp.Refs[0].(event.Tag),
+				Type: encOp.Refs[1].(string),
+			}
+			pc.targetOp(op, &q.handlers)
+		case ops.TypeOffer:
+			op := transfer.OfferOp{
+				Tag:  encOp.Refs[0].(event.Tag),
+				Type: encOp.Refs[1].(string),
+				Data: encOp.Refs[2].(io.ReadCloser),
+			}
+			pc.offerOp(op, &q.handlers)
+		case ops.TypeActionInput:
+			act := system.Action(encOp.Data[1])
+			pc.actionInputOp(act)
+
+		// Key ops.
+		case ops.TypeKeyFocus:
+			tag, _ := encOp.Refs[0].(event.Tag)
+			op := key.FocusOp{
+				Tag: tag,
+			}
+			kc.focusOp(op.Tag)
+		case ops.TypeKeySoftKeyboard:
+			op := key.SoftKeyboardOp{
+				Show: encOp.Data[1] != 0,
+			}
+			kc.softKeyboard(op.Show)
+		case ops.TypeKeyInput:
+			filter := key.Set(*encOp.Refs[1].(*string))
+			op := key.InputOp{
+				Tag:  encOp.Refs[0].(event.Tag),
+				Hint: key.InputHint(encOp.Data[1]),
+				Keys: filter,
+			}
+			a := pc.currentArea()
+			b := pc.currentAreaBounds()
+			pc.keyInputOp(op)
+			kc.inputOp(op, a, b)
+		case ops.TypeSnippet:
+			op := key.SnippetOp{
+				Tag: encOp.Refs[0].(event.Tag),
+				Snippet: key.Snippet{
+					Range: key.Range{
+						Start: int(int32(bo.Uint32(encOp.Data[1:]))),
+						End:   int(int32(bo.Uint32(encOp.Data[5:]))),
+					},
+					Text: *(encOp.Refs[1].(*string)),
+				},
+			}
+			kc.snippetOp(op)
+		case ops.TypeSelection:
+			op := key.SelectionOp{
+				Tag: encOp.Refs[0].(event.Tag),
+				Range: key.Range{
+					Start: int(int32(bo.Uint32(encOp.Data[1:]))),
+					End:   int(int32(bo.Uint32(encOp.Data[5:]))),
+				},
+				Caret: key.Caret{
+					Pos: f32.Point{
+						X: math.Float32frombits(bo.Uint32(encOp.Data[9:])),
+						Y: math.Float32frombits(bo.Uint32(encOp.Data[13:])),
+					},
+					Ascent:  math.Float32frombits(bo.Uint32(encOp.Data[17:])),
+					Descent: math.Float32frombits(bo.Uint32(encOp.Data[21:])),
+				},
+			}
+			kc.selectionOp(t, op)
+
+		// Semantic ops.
+		case ops.TypeSemanticLabel:
+			lbl := *encOp.Refs[0].(*string)
+			pc.semanticLabel(lbl)
+		case ops.TypeSemanticDesc:
+			desc := *encOp.Refs[0].(*string)
+			pc.semanticDesc(desc)
+		case ops.TypeSemanticClass:
+			class := semantic.ClassOp(encOp.Data[1])
+			pc.semanticClass(class)
+		case ops.TypeSemanticSelected:
+			if encOp.Data[1] != 0 {
+				pc.semanticSelected(true)
+			} else {
+				pc.semanticSelected(false)
+			}
+		case ops.TypeSemanticEnabled:
+			if encOp.Data[1] != 0 {
+				pc.semanticEnabled(true)
+			} else {
+				pc.semanticEnabled(false)
+			}
+		}
+	}
+}
+
+// Profiling reports whether there was profile handlers in the
+// most recent Frame call.
+func (q *Router) Profiling() bool {
+	return len(q.profHandlers) > 0
+}
+
+// WakeupTime returns the most recent time for doing another frame,
+// as determined from the last call to Frame.
+func (q *Router) WakeupTime() (time.Time, bool) {
+	return q.wakeupTime, q.wakeup
+}
+
+func (h *handlerEvents) init() {
+	if h.handlers == nil {
+		h.handlers = make(map[event.Tag][]event.Event)
+	}
+}
+
+func (h *handlerEvents) AddNoRedraw(k event.Tag, e event.Event) {
+	h.init()
+	h.handlers[k] = append(h.handlers[k], e)
+}
+
+func (h *handlerEvents) Add(k event.Tag, e event.Event) {
+	h.AddNoRedraw(k, e)
+	h.hadEvents = true
+}
+
+func (h *handlerEvents) HadEvents() bool {
+	u := h.hadEvents
+	h.hadEvents = false
+	return u
+}
+
+func (h *handlerEvents) Events(k event.Tag) []event.Event {
+	if events, ok := h.handlers[k]; ok {
+		h.handlers[k] = h.handlers[k][:0]
+		return events
+	}
+	return nil
+}
+
+func (h *handlerEvents) Clear() {
+	for k := range h.handlers {
+		delete(h.handlers, k)
+	}
+}
+
+func decodeProfileOp(d []byte, refs []interface{}) profile.Op {
+	if ops.OpType(d[0]) != ops.TypeProfile {
+		panic("invalid op")
+	}
+	return profile.Op{
+		Tag: refs[0].(event.Tag),
+	}
+}
+
+func decodeInvalidateOp(d []byte) op.InvalidateOp {
+	bo := binary.LittleEndian
+	if ops.OpType(d[0]) != ops.TypeInvalidate {
+		panic("invalid op")
+	}
+	var o op.InvalidateOp
+	if nanos := bo.Uint64(d[1:]); nanos > 0 {
+		o.At = time.Unix(0, int64(nanos))
+	}
+	return o
+}
+
+func (s SemanticGestures) String() string {
+	var gestures []string
+	if s&ClickGesture != 0 {
+		gestures = append(gestures, "Click")
+	}
+	return strings.Join(gestures, ",")
+}

io/router/semantic_test.go

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: Unlicense OR MIT
 
-package input
+package router
 
 import (
 	"fmt"
@@ -9,7 +9,6 @@ import (
 	"testing"
 
 	"gioui.org/f32"
-	"gioui.org/io/event"
 	"gioui.org/io/pointer"
 	"gioui.org/io/semantic"
 	"gioui.org/op"
@@ -75,19 +74,13 @@ func TestSemanticTree(t *testing.T) {
 
 func TestSemanticDescription(t *testing.T) {
 	var ops op.Ops
-
+	pointer.InputOp{Tag: new(int), Kinds: pointer.Press | pointer.Release}.Add(&ops)
-	h := new(int)
-	event.Op(&ops, h)
 	semantic.DescriptionOp("description").Add(&ops)
 	semantic.LabelOp("label").Add(&ops)
 	semantic.Button.Add(&ops)
 	semantic.EnabledOp(false).Add(&ops)
 	semantic.SelectedOp(true).Add(&ops)
 	var r Router
-	events(&r, -1, pointer.Filter{
-		Target: h,
-		Kinds:  pointer.Press | pointer.Release,
-	})
 	r.Frame(&ops)
 	tree := r.AppendSemantics(nil)
 	got := tree[0].Desc

io/system/system.go

@@ -0,0 +1,89 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+// Package system contains events usually handled at the top-level
+// program level.
+package system
+
+import (
+	"image"
+	"time"
+
+	"gioui.org/io/event"
+	"gioui.org/op"
+	"gioui.org/unit"
+)
+
+// A FrameEvent requests a new frame in the form of a list of
+// operations that describes what to display and how to handle
+// input.
+type FrameEvent struct {
+	// Now is the current animation. Use Now instead of time.Now to
+	// synchronize animation and to avoid the time.Now call overhead.
+	Now time.Time
+	// Metric converts device independent dp and sp to device pixels.
+	Metric unit.Metric
+	// Size is the dimensions of the window.
+	Size image.Point
+	// Insets represent the space occupied by system decorations and controls.
+	Insets Insets
+	// Frame completes the FrameEvent by drawing the graphical operations
+	// from ops into the window.
+	Frame func(frame *op.Ops)
+	// Queue supplies the events for event handlers.
+	Queue event.Queue
+}
+
+// DestroyEvent is the last event sent through
+// a window event channel.
+type DestroyEvent struct {
+	// Err is nil for normal window closures. If a
+	// window is prematurely closed, Err is the cause.
+	Err error
+}
+
+// Insets is the space taken up by
+// system decoration such as translucent
+// system bars and software keyboards.
+type Insets struct {
+	// Values are in pixels.
+	Top, Bottom, Left, Right unit.Dp
+}
+
+// A StageEvent is generated whenever the stage of a
+// Window changes.
+type StageEvent struct {
+	Stage Stage
+}
+
+// Stage of a Window.
+type Stage uint8
+
+const (
+	// StagePaused is the stage for windows that have no on-screen representation.
+	// Paused windows don't receive FrameEvent.
+	StagePaused Stage = iota
+	// StageInactive is the stage for windows that are visible, but not active.
+	// Inactive windows receive FrameEvent.
+	StageInactive
+	// StageRunning is for active and visible Windows.
+	// Running windows receive FrameEvent.
+	StageRunning
+)
+
+// String implements fmt.Stringer.
+func (l Stage) String() string {
+	switch l {
+	case StagePaused:
+		return "StagePaused"
+	case StageInactive:
+		return "StageInactive"
+	case StageRunning:
+		return "StageRunning"
+	default:
+		panic("unexpected Stage value")
+	}
+}
+
+func (FrameEvent) ImplementsEvent()   {}
+func (StageEvent) ImplementsEvent()   {}
+func (DestroyEvent) ImplementsEvent() {}

io/transfer/transfer.go

@@ -2,11 +2,11 @@
 //
 // The transfer protocol is as follows:
 //
-//   - Data sources use [SourceFilter] to receive an [InitiateEvent] when a drag
+//   - Data sources are registered with SourceOps, data targets with TargetOps.
-//     is initiated, and an [RequestEvent] for each initiation of a data transfer.
+//   - A data source receives a RequestEvent when a transfer is initiated.
-//     Sources respond to requests with [OfferCmd].
+//     It must respond with an OfferOp.
-//   - Data targets use [TargetFilter] to receive an [DataEvent] for receiving data.
+//   - The target receives a DataEvent when transferring to it. It must close
-//     The target must close the data event after use.
+//     the event data after use.
 //
 // When a user initiates a pointer-guided drag and drop transfer, the
 // source as well as all potential targets receive an InitiateEvent.
@@ -20,11 +20,29 @@ package transfer
 import (
 	"io"
 
+	"gioui.org/internal/ops"
 	"gioui.org/io/event"
+	"gioui.org/op"
 )
 
-// OfferCmd is used by data sources as a response to a RequestEvent.
+// SourceOp registers a tag as a data source for a MIME type.
-type OfferCmd struct {
+// Use multiple SourceOps if a tag supports multiple types.
+type SourceOp struct {
+	Tag event.Tag
+	// Type is the MIME type supported by this source.
+	Type string
+}
+
+// TargetOp registers a tag as a data target.
+// Use multiple TargetOps if a tag supports multiple types.
+type TargetOp struct {
+	Tag event.Tag
+	// Type is the MIME type accepted by this target.
+	Type string
+}
+
+// OfferOp is used by data sources as a response to a RequestEvent.
+type OfferOp struct {
 	Tag event.Tag
 	// Type is the MIME type of Data.
 	// It must be the Type from the corresponding RequestEvent.
@@ -32,33 +50,32 @@ type OfferCmd struct {
 	// Data contains the offered data. It is closed when the
 	// transfer is complete or cancelled.
 	// Data must be kept valid until closed, and it may be used from
-	// a goroutine separate from the one processing the frame.
+	// a goroutine separate from the one processing the frame..
 	Data io.ReadCloser
 }
 
-func (OfferCmd) ImplementsCommand() {}
+func (op SourceOp) Add(o *op.Ops) {
-
+	data := ops.Write2(&o.Internal, ops.TypeSourceLen, op.Tag, op.Type)
-// SourceFilter filters for any [RequestEvent] that match a MIME type
+	data[0] = byte(ops.TypeSource)
-// as well as [InitiateEvent] and [CancelEvent].
-// Use multiple filters to offer multiple types.
-type SourceFilter struct {
-	// Target is a tag included in a previous event.Op.
-	Target event.Tag
-	// Type is the MIME type supported by this source.
-	Type string
 }
 
-// TargetFilter filters for any [DataEvent] whose type matches a MIME type
+func (op TargetOp) Add(o *op.Ops) {
-// as well as [CancelEvent]. Use multiple filters to accept multiple types.
+	data := ops.Write2(&o.Internal, ops.TypeTargetLen, op.Tag, op.Type)
-type TargetFilter struct {
+	data[0] = byte(ops.TypeTarget)
-	// Target is a tag included in a previous event.Op.
+}
-	Target event.Tag
+
-	// Type is the MIME type accepted by this target.
+// Add the offer to the list of operations.
-	Type string
+// It panics if the Data field is not set.
+func (op OfferOp) Add(o *op.Ops) {
+	if op.Data == nil {
+		panic("invalid nil data in OfferOp")
+	}
+	data := ops.Write3(&o.Internal, ops.TypeOfferLen, op.Tag, op.Type, op.Data)
+	data[0] = byte(ops.TypeOffer)
 }
 
 // RequestEvent requests data from a data source. The source must
-// respond with an OfferCmd.
+// respond with an OfferOp.
 type RequestEvent struct {
 	// Type is the first matched type between the source and the target.
 	Type string
@@ -90,6 +107,3 @@ type DataEvent struct {
 }
 
 func (DataEvent) ImplementsEvent() {}
-
-func (SourceFilter) ImplementsFilter() {}
-func (TargetFilter) ImplementsFilter() {}

layout/context.go

@@ -3,9 +3,10 @@
 package layout
 
 import (
+	"image"
 	"time"
 
-	"gioui.org/io/input"
+	"gioui.org/io/event"
 	"gioui.org/io/system"
 	"gioui.org/op"
 	"gioui.org/unit"
@@ -20,6 +21,9 @@ type Context struct {
 	Constraints Constraints
 
 	Metric unit.Metric
+	// By convention, a nil Queue is a signal to widgets to draw themselves
+	// in a disabled state.
+	Queue event.Queue
 	// Now is the animation time.
 	Now time.Time
 
@@ -28,10 +32,46 @@ type Context struct {
 	// Interested users must look up and populate these values manually.
 	Locale system.Locale
 
-	input.Source
 	*op.Ops
 }
 
+// NewContext is a shorthand for
+//
+//	Context{
+//	  Ops: ops,
+//	  Now: e.Now,
+//	  Queue: e.Queue,
+//	  Config: e.Config,
+//	  Constraints: Exact(e.Size),
+//	}
+//
+// NewContext calls ops.Reset and adjusts ops for e.Insets.
+func NewContext(ops *op.Ops, e system.FrameEvent) Context {
+	ops.Reset()
+
+	size := e.Size
+
+	if e.Insets != (system.Insets{}) {
+		left := e.Metric.Dp(e.Insets.Left)
+		top := e.Metric.Dp(e.Insets.Top)
+		op.Offset(image.Point{
+			X: left,
+			Y: top,
+		}).Add(ops)
+
+		size.X -= left + e.Metric.Dp(e.Insets.Right)
+		size.Y -= top + e.Metric.Dp(e.Insets.Bottom)
+	}
+
+	return Context{
+		Ops:         ops,
+		Now:         e.Now,
+		Queue:       e.Queue,
+		Metric:      e.Metric,
+		Constraints: Exact(size),
+	}
+}
+
 // Dp converts v to pixels.
 func (c Context) Dp(v unit.Dp) int {
 	return c.Metric.Dp(v)
@@ -42,9 +82,21 @@ func (c Context) Sp(v unit.Sp) int {
 	return c.Metric.Sp(v)
 }
 
-// Disabled returns a copy of this context with a disabled Source,
+// Events returns the events available for the key. If no
-// blocking widgets from changing its state and receiving events.
+// queue is configured, Events returns nil.
+func (c Context) Events(k event.Tag) []event.Event {
+	if c.Queue == nil {
+		return nil
+	}
+	return c.Queue.Events(k)
+}
+
+// Disabled returns a copy of this context with a nil Queue,
+// blocking events to widgets using it.
+//
+// By convention, a nil Queue is a signal to widgets to draw themselves
+// in a disabled state.
 func (c Context) Disabled() Context {
-	c.Source = input.Source{}
+	c.Queue = nil
 	return c
 }

layout/list.go

@@ -144,25 +144,7 @@ func (l *List) Dragging() bool {
 }
 
 func (l *List) update(gtx Context) {
-	min, max := int(-inf), int(inf)
+	d := l.scroll.Update(gtx.Metric, gtx, gtx.Now, gesture.Axis(l.Axis))
-	if l.Position.First == 0 {
-		// Use the size of the invisible part as scroll boundary.
-		min = -l.Position.Offset
-		if min > 0 {
-			min = 0
-		}
-	}
-	if l.Position.First+l.Position.Count == l.len {
-		max = -l.Position.OffsetLast
-		if max < 0 {
-			max = 0
-		}
-	}
-	scrollRange := image.Rectangle{
-		Min: l.Axis.Convert(image.Pt(min, 0)),
-		Max: l.Axis.Convert(image.Pt(max, 0)),
-	}
-	d := l.scroll.Update(gtx.Metric, gtx.Source, gtx.Now, gesture.Axis(l.Axis), scrollRange)
 	l.scrollDelta = d
 	l.Position.Offset += d
 }
@@ -350,7 +332,25 @@ func (l *List) layout(ops *op.Ops, macro op.MacroOp) Dimensions {
 	call := macro.Stop()
 	defer clip.Rect(image.Rectangle{Max: dims}).Push(ops).Pop()
 
-	l.scroll.Add(ops)
+	min, max := int(-inf), int(inf)
+	if l.Position.First == 0 {
+		// Use the size of the invisible part as scroll boundary.
+		min = -l.Position.Offset
+		if min > 0 {
+			min = 0
+		}
+	}
+	if l.Position.First+l.Position.Count == l.len {
+		max = -l.Position.OffsetLast
+		if max < 0 {
+			max = 0
+		}
+	}
+	scrollRange := image.Rectangle{
+		Min: l.Axis.Convert(image.Pt(min, 0)),
+		Max: l.Axis.Convert(image.Pt(max, 0)),
+	}
+	l.scroll.Add(ops, scrollRange)
 
 	call.Add(ops)
 	return Dimensions{Size: dims}

layout/list_test.go

@@ -8,8 +8,8 @@ import (
 
 	"gioui.org/f32"
 	"gioui.org/io/event"
-	"gioui.org/io/input"
 	"gioui.org/io/pointer"
+	"gioui.org/io/router"
 	"gioui.org/op"
 )
 
@@ -64,13 +64,13 @@ func TestListScrollToEnd(t *testing.T) {
 
 func TestListPosition(t *testing.T) {
 	_s := func(e ...event.Event) []event.Event { return e }
-	r := new(input.Router)
+	r := new(router.Router)
 	gtx := Context{
 		Ops: new(op.Ops),
 		Constraints: Constraints{
 			Max: image.Pt(20, 10),
 		},
-		Source: r.Source(),
+		Queue: r,
 	}
 	el := func(gtx Context, idx int) Dimensions {
 		return Dimensions{Size: image.Pt(10, 10)}

op/op.go

@@ -53,6 +53,7 @@ The MacroOp records a list of operations to be executed later:
 	ops := new(op.Ops)
 	macro := op.Record(ops)
 	// Record operations by adding them.
+	op.InvalidateOp{}.Add(ops)
 	...
 	// End recording.
 	call := macro.Stop()
@@ -95,9 +96,9 @@ type CallOp struct {
 	end   ops.PC
 }
 
-// InvalidateCmd requests a redraw at the given time. Use
+// InvalidateOp requests a redraw at the given time. Use
 // the zero value to request an immediate redraw.
-type InvalidateCmd struct {
+type InvalidateOp struct {
 	At time.Time
 }
 
@@ -180,6 +181,19 @@ func (c CallOp) Add(o *Ops) {
 	ops.AddCall(&o.Internal, c.ops, c.start, c.end)
 }
 
+func (r InvalidateOp) Add(o *Ops) {
+	data := ops.Write(&o.Internal, ops.TypeRedrawLen)
+	data[0] = byte(ops.TypeInvalidate)
+	bo := binary.LittleEndian
+	// UnixNano cannot represent the zero time.
+	if t := r.At; !t.IsZero() {
+		nanos := t.UnixNano()
+		if nanos > 0 {
+			bo.PutUint64(data[1:], uint64(nanos))
+		}
+	}
+}
+
 // Offset converts an offset to a TransformOp.
 func Offset(off image.Point) TransformOp {
 	offf := f32.Pt(float32(off.X), float32(off.Y))
@@ -226,5 +240,3 @@ func (t TransformStack) Pop() {
 	data := ops.Write(t.ops, ops.TypePopTransformLen)
 	data[0] = byte(ops.TypePopTransform)
 }
-
-func (InvalidateCmd) ImplementsCommand() {}

text/lru.go

@@ -163,6 +163,10 @@ type layoutKey struct {
 	lineHeightScale    float32
 }
 
+type pathKey struct {
+	gidHash uint64
+}
+
 const maxSize = 1000
 
 func gidsEqual(a []glyphInfo, glyphs []Glyph) bool {

widget/bool.go

@@ -16,7 +16,7 @@ type Bool struct {
 // Update the widget state and report whether Value was changed.
 func (b *Bool) Update(gtx layout.Context) bool {
 	changed := false
-	for b.clk.clicked(b, gtx) {
+	for b.clk.Clicked(gtx) {
 		b.Value = !b.Value
 		changed = true
 	}
@@ -33,15 +33,20 @@ func (b *Bool) Pressed() bool {
 	return b.clk.Pressed()
 }
 
+// Focused reports whether b has focus.
+func (b *Bool) Focused() bool {
+	return b.clk.Focused()
+}
+
 func (b *Bool) History() []Press {
 	return b.clk.History()
 }
 
 func (b *Bool) Layout(gtx layout.Context, w layout.Widget) layout.Dimensions {
 	b.Update(gtx)
-	dims := b.clk.layout(b, gtx, func(gtx layout.Context) layout.Dimensions {
+	dims := b.clk.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
 		semantic.SelectedOp(b.Value).Add(gtx.Ops)
-		semantic.EnabledOp(gtx.Enabled()).Add(gtx.Ops)
+		semantic.EnabledOp(gtx.Queue != nil).Add(gtx.Ops)
 		return w(gtx)
 	})
 	return dims

widget/buffer.go

@@ -11,6 +11,9 @@ import (
 
 // editBuffer implements a gap buffer for text editing.
 type editBuffer struct {
+	// pos is the byte position for Read and ReadRune.
+	pos int
+
 	// The gap start and end in bytes.
 	gapstart, gapend int
 	text             []byte

widget/button.go

@@ -7,7 +7,6 @@ import (
 	"time"
 
 	"gioui.org/gesture"
-	"gioui.org/io/event"
 	"gioui.org/io/key"
 	"gioui.org/io/pointer"
 	"gioui.org/io/semantic"
@@ -18,11 +17,16 @@ import (
 
 // Clickable represents a clickable area.
 type Clickable struct {
-	click   gesture.Click
+	click gesture.Click
+	// clicks is for saved clicks to support Clicked.
+	clicks  []Click
 	history []Press
 
+	keyTag        struct{}
+	requestFocus  bool
 	requestClicks int
-	pressedKey    key.Name
+	focused       bool
+	pressedKey    string
 }
 
 // Click represents a click.
@@ -49,14 +53,19 @@ func (b *Clickable) Click() {
 	b.requestClicks++
 }
 
-// Clicked calls Update and reports whether a click was registered.
+// Clicked reports whether there are pending clicks. If so, Clicked
+// removes the earliest click.
 func (b *Clickable) Clicked(gtx layout.Context) bool {
-	return b.clicked(b, gtx)
+	if len(b.clicks) > 0 {
-}
+		b.clicks = b.clicks[1:]
-
+		return true
-func (b *Clickable) clicked(t event.Tag, gtx layout.Context) bool {
+	}
-	_, clicked := b.update(t, gtx)
+	b.clicks = b.Update(gtx)
-	return clicked
+	if len(b.clicks) > 0 {
+		b.clicks = b.clicks[1:]
+		return true
+	}
+	return false
 }
 
 // Hovered reports whether a pointer is over the element.
@@ -69,6 +78,16 @@ func (b *Clickable) Pressed() bool {
 	return b.click.Pressed()
 }
 
+// Focus requests the input focus for the element.
+func (b *Clickable) Focus() {
+	b.requestFocus = true
+}
+
+// Focused reports whether b has focus.
+func (b *Clickable) Focused() bool {
+	return b.focused
+}
+
 // History is the past pointer presses useful for drawing markers.
 // History is retained for a short duration (about a second).
 func (b *Clickable) History() []Press {
@@ -77,34 +96,36 @@ func (b *Clickable) History() []Press {
 
 // Layout and update the button state.
 func (b *Clickable) Layout(gtx layout.Context, w layout.Widget) layout.Dimensions {
-	return b.layout(b, gtx, w)
+	b.Update(gtx)
-}
-
-func (b *Clickable) layout(t event.Tag, gtx layout.Context, w layout.Widget) layout.Dimensions {
-	for {
-		_, ok := b.update(t, gtx)
-		if !ok {
-			break
-		}
-	}
 	m := op.Record(gtx.Ops)
 	dims := w(gtx)
 	c := m.Stop()
 	defer clip.Rect(image.Rectangle{Max: dims.Size}).Push(gtx.Ops).Pop()
-	semantic.EnabledOp(gtx.Enabled()).Add(gtx.Ops)
+	enabled := gtx.Queue != nil
+	semantic.EnabledOp(enabled).Add(gtx.Ops)
 	b.click.Add(gtx.Ops)
-	event.Op(gtx.Ops, t)
+	if enabled {
+		keys := key.Set("⏎|Space")
+		if !b.focused {
+			keys = ""
+		}
+		key.InputOp{Tag: &b.keyTag, Keys: keys}.Add(gtx.Ops)
+	}
 	c.Add(gtx.Ops)
 	return dims
 }
 
-// Update the button state by processing events, and return the next
+// Update the button state by processing events, and return the resulting
-// click, if any.
+// clicks, if any.
-func (b *Clickable) Update(gtx layout.Context) (Click, bool) {
+func (b *Clickable) Update(gtx layout.Context) []Click {
-	return b.update(b, gtx)
+	b.clicks = nil
-}
+	if gtx.Queue == nil {
-
+		b.focused = false
-func (b *Clickable) update(t event.Tag, gtx layout.Context) (Click, bool) {
+	}
+	if b.requestFocus {
+		key.FocusOp{Tag: &b.keyTag}.Add(gtx.Ops)
+		b.requestFocus = false
+	}
 	for len(b.history) > 0 {
 		c := b.history[0]
 		if c.End.IsZero() || gtx.Now.Sub(c.End) < 1*time.Second {
@@ -113,26 +134,23 @@ func (b *Clickable) update(t event.Tag, gtx layout.Context) (Click, bool) {
 		n := copy(b.history, b.history[1:])
 		b.history = b.history[:n]
 	}
+	var clicks []Click
 	if c := b.requestClicks; c > 0 {
 		b.requestClicks = 0
-		return Click{
+		clicks = append(clicks, Click{
 			NumClicks: c,
-		}, true
+		})
 	}
-	for {
+	for _, e := range b.click.Update(gtx) {
-		e, ok := b.click.Update(gtx.Source)
-		if !ok {
-			break
-		}
 		switch e.Kind {
 		case gesture.KindClick:
 			if l := len(b.history); l > 0 {
 				b.history[l-1].End = gtx.Now
 			}
-			return Click{
+			clicks = append(clicks, Click{
 				Modifiers: e.Modifiers,
 				NumClicks: e.NumClicks,
-			}, true
+			})
 		case gesture.KindCancel:
 			for i := range b.history {
 				b.history[i].Cancelled = true
@@ -142,7 +160,7 @@ func (b *Clickable) update(t event.Tag, gtx layout.Context) (Click, bool) {
 			}
 		case gesture.KindPress:
 			if e.Source == pointer.Mouse {
-				gtx.Execute(key.FocusCmd{Tag: t})
+				key.FocusOp{Tag: &b.keyTag}.Add(gtx.Ops)
 			}
 			b.history = append(b.history, Press{
 				Position: e.Position,
@@ -150,22 +168,15 @@ func (b *Clickable) update(t event.Tag, gtx layout.Context) (Click, bool) {
 			})
 		}
 	}
-	for {
+	for _, e := range gtx.Events(&b.keyTag) {
-		e, ok := gtx.Event(
-			key.FocusFilter{Target: t},
-			key.Filter{Focus: t, Name: key.NameReturn},
-			key.Filter{Focus: t, Name: key.NameSpace},
-		)
-		if !ok {
-			break
-		}
 		switch e := e.(type) {
 		case key.FocusEvent:
-			if e.Focus {
+			b.focused = e.Focus
+			if !b.focused {
 				b.pressedKey = ""
 			}
 		case key.Event:
-			if !gtx.Focused(t) {
+			if !b.focused {
 				break
 			}
 			if e.Name != key.NameReturn && e.Name != key.NameSpace {
@@ -180,12 +191,12 @@ func (b *Clickable) update(t event.Tag, gtx layout.Context) (Click, bool) {
 				}
 				// only register a key as a click if the key was pressed and released while this button was focused
 				b.pressedKey = ""
-				return Click{
+				clicks = append(clicks, Click{
 					Modifiers: e.Modifiers,
 					NumClicks: 1,
-				}, true
+				})
 			}
 		}
 	}
-	return Click{}, false
+	return clicks
 }

widget/button_test.go

@@ -6,8 +6,9 @@ import (
 	"image"
 	"testing"
 
-	"gioui.org/io/input"
 	"gioui.org/io/key"
+	"gioui.org/io/router"
+	"gioui.org/io/system"
 	"gioui.org/layout"
 	"gioui.org/op"
 	"gioui.org/widget"
@@ -15,14 +16,12 @@ import (
 
 func TestClickable(t *testing.T) {
 	var (
-		r  input.Router
+		ops op.Ops
-		b1 widget.Clickable
+		r   router.Router
-		b2 widget.Clickable
+		b1  widget.Clickable
+		b2  widget.Clickable
 	)
-	gtx := layout.Context{
+	gtx := layout.NewContext(&ops, system.FrameEvent{Queue: &r})
-		Ops:    new(op.Ops),
-		Source: r.Source(),
-	}
 	layout := func() {
 		b1.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
 			return layout.Dimensions{Size: image.Pt(100, 100)}
@@ -33,18 +32,23 @@ func TestClickable(t *testing.T) {
 		})
 	}
 	frame := func() {
-		gtx.Reset()
+		ops.Reset()
 		layout()
 		r.Frame(gtx.Ops)
 	}
-	gtx.Execute(key.FocusCmd{Tag: &b1})
+	// frame: request focus for button 1
+	b1.Focus()
 	frame()
-	if !gtx.Focused(&b1) {
+	// frame: gain focus for button 1
+	frame()
+	if !b1.Focused() {
 		t.Error("button 1 did not gain focus")
 	}
-	if gtx.Focused(&b2) {
+	if b2.Focused() {
 		t.Error("button 2 should not have focus")
 	}
+	// frame: press & release return
+	frame()
 	r.Queue(
 		key.Event{
 			Name:  key.NameReturn,
@@ -61,30 +65,36 @@ func TestClickable(t *testing.T) {
 	if b2.Clicked(gtx) {
 		t.Error("button 2 got clicked when it did not have focus")
 	}
+	// frame: press return down
 	r.Queue(
 		key.Event{
 			Name:  key.NameReturn,
 			State: key.Press,
 		},
 	)
+	frame()
 	if b1.Clicked(gtx) {
 		t.Error("button 1 got clicked, even if it only got return press")
 	}
+	// frame: request focus for button 2
+	b2.Focus()
 	frame()
-	gtx.Execute(key.FocusCmd{Tag: &b2})
+	// frame: gain focus for button 2
 	frame()
-	if gtx.Focused(&b1) {
+	if b1.Focused() {
 		t.Error("button 1 should not have focus")
 	}
-	if !gtx.Focused(&b2) {
+	if !b2.Focused() {
 		t.Error("button 2 did not gain focus")
 	}
+	// frame: release return
 	r.Queue(
 		key.Event{
 			Name:  key.NameReturn,
 			State: key.Release,
 		},
 	)
+	frame()
 	if b1.Clicked(gtx) {
 		t.Error("button 1 got clicked, even if it had lost focus")
 	}

widget/decorations.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"math/bits"
 
+	"gioui.org/gesture"
 	"gioui.org/io/system"
 	"gioui.org/layout"
 	"gioui.org/op/clip"
@@ -11,7 +12,11 @@ import (
 
 // Decorations handles the states of window decorations.
 type Decorations struct {
-	clicks    map[int]*Clickable
+	clicks map[int]*Clickable
+	resize [8]struct {
+		gesture.Hover
+		gesture.Drag
+	}
 	maximized bool
 }
 

widget/dnd.go

@@ -5,7 +5,6 @@ import (
 
 	"gioui.org/f32"
 	"gioui.org/gesture"
-	"gioui.org/io/event"
 	"gioui.org/io/pointer"
 	"gioui.org/io/transfer"
 	"gioui.org/layout"
@@ -18,20 +17,24 @@ type Draggable struct {
 	// Type contains the MIME type and matches transfer.SourceOp.
 	Type string
 
-	drag  gesture.Drag
+	handle struct{}
-	click f32.Point
+	drag   gesture.Drag
-	pos   f32.Point
+	click  f32.Point
+	pos    f32.Point
 }
 
 func (d *Draggable) Layout(gtx layout.Context, w, drag layout.Widget) layout.Dimensions {
-	if !gtx.Enabled() {
+	if gtx.Queue == nil {
 		return w(gtx)
 	}
 	dims := w(gtx)
 
 	stack := clip.Rect{Max: dims.Size}.Push(gtx.Ops)
 	d.drag.Add(gtx.Ops)
-	event.Op(gtx.Ops, d)
+	transfer.SourceOp{
+		Tag:  &d.handle,
+		Type: d.Type,
+	}.Add(gtx.Ops)
 	stack.Pop()
 
 	if drag != nil && d.drag.Pressed() {
@@ -53,11 +56,7 @@ func (d *Draggable) Dragging() bool {
 // requested to offer data, if any
 func (d *Draggable) Update(gtx layout.Context) (mime string, requested bool) {
 	pos := d.pos
-	for {
+	for _, ev := range d.drag.Update(gtx.Metric, gtx.Queue, gesture.Both) {
-		ev, ok := d.drag.Update(gtx.Metric, gtx.Source, gesture.Both)
-		if !ok {
-			break
-		}
 		switch ev.Kind {
 		case pointer.Press:
 			d.click = ev.Position
@@ -68,12 +67,8 @@ func (d *Draggable) Update(gtx layout.Context) (mime string, requested bool) {
 	}
 	d.pos = pos
 
-	for {
+	for _, ev := range gtx.Queue.Events(&d.handle) {
-		e, ok := gtx.Event(transfer.SourceFilter{Target: d, Type: d.Type})
+		if e, ok := ev.(transfer.RequestEvent); ok {
-		if !ok {
-			break
-		}
-		if e, ok := e.(transfer.RequestEvent); ok {
 			return e.Type, true
 		}
 	}
@@ -82,8 +77,12 @@ func (d *Draggable) Update(gtx layout.Context) (mime string, requested bool) {
 
 // Offer the data ready for a drop. Must be called after being Requested.
 // The mime must be one in the requested list.
-func (d *Draggable) Offer(gtx layout.Context, mime string, data io.ReadCloser) {
+func (d *Draggable) Offer(ops *op.Ops, mime string, data io.ReadCloser) {
-	gtx.Execute(transfer.OfferCmd{Tag: d, Type: mime, Data: data})
+	transfer.OfferOp{
+		Tag:  &d.handle,
+		Type: mime,
+		Data: data,
+	}.Add(ops)
 }
 
 // Pos returns the drag position relative to its initial click position.

widget/dnd_test.go

@@ -5,9 +5,8 @@ import (
 	"testing"
 
 	"gioui.org/f32"
-	"gioui.org/io/event"
-	"gioui.org/io/input"
 	"gioui.org/io/pointer"
+	"gioui.org/io/router"
 	"gioui.org/io/transfer"
 	"gioui.org/layout"
 	"gioui.org/op"
@@ -15,27 +14,27 @@ import (
 )
 
 func TestDraggable(t *testing.T) {
-	var r input.Router
+	var r router.Router
 	gtx := layout.Context{
 		Constraints: layout.Exact(image.Pt(100, 100)),
-		Source:      r.Source(),
+		Queue:       &r,
 		Ops:         new(op.Ops),
 	}
 
 	drag := &Draggable{
 		Type: "file",
 	}
-	tgt := new(int)
 	defer pointer.PassOp{}.Push(gtx.Ops).Pop()
 	dims := drag.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
 		return layout.Dimensions{Size: gtx.Constraints.Min}
 	}, nil)
 	stack := clip.Rect{Max: dims.Size}.Push(gtx.Ops)
-	event.Op(gtx.Ops, tgt)
+	transfer.TargetOp{
+		Tag:  drag,
+		Type: drag.Type,
+	}.Add(gtx.Ops)
 	stack.Pop()
 
-	drag.Update(gtx)
-	r.Event(transfer.TargetFilter{Target: tgt, Type: drag.Type})
 	r.Frame(gtx.Ops)
 	r.Queue(
 		pointer.Event{
@@ -52,28 +51,21 @@ func TestDraggable(t *testing.T) {
 		},
 	)
 	ofr := &offer{data: "hello"}
-	drag.Update(gtx)
+	drag.Offer(gtx.Ops, "file", ofr)
-	r.Event(transfer.TargetFilter{Target: tgt, Type: drag.Type})
+	r.Frame(gtx.Ops)
-	drag.Offer(gtx, "file", ofr)
 
-	e, ok := r.Event(transfer.TargetFilter{Target: tgt, Type: drag.Type})
+	evs := r.Events(drag)
-	if !ok {
+	if len(evs) != 1 {
-		t.Fatalf("expected event")
+		t.Fatalf("expected 1 event, got %d", len(evs))
 	}
-	ev := e.(transfer.DataEvent)
+	ev := evs[0].(transfer.DataEvent)
+	ev.Open = nil
 	if got, want := ev.Type, "file"; got != want {
 		t.Errorf("expected %v; got %v", got, want)
 	}
 	if ofr.closed {
 		t.Error("offer closed prematurely")
 	}
-	e, ok = r.Event(transfer.TargetFilter{Target: tgt, Type: drag.Type})
-	if !ok {
-		t.Fatalf("expected event")
-	}
-	if _, ok := e.(transfer.CancelEvent); !ok {
-		t.Fatalf("expected transfer.CancelEvent event")
-	}
 	r.Frame(gtx.Ops)
 	if !ofr.closed {
 		t.Error("offer was not closed")

widget/doc.go

@@ -2,5 +2,5 @@
 
 // Package widget implements state tracking and event handling of
 // common user interface controls. To draw widgets, use a theme
-// packages such as package [gioui.org/widget/material].
+// packages such as package gioui.org/widget/material.
 package widget

widget/editor.go

@@ -21,7 +21,6 @@ import (
 	"gioui.org/io/pointer"
 	"gioui.org/io/semantic"
 	"gioui.org/io/system"
-	"gioui.org/io/transfer"
 	"gioui.org/layout"
 	"gioui.org/op"
 	"gioui.org/op/clip"
@@ -70,8 +69,11 @@ type Editor struct {
 	buffer *editBuffer
 	// scratch is a byte buffer that is reused to efficiently read portions of text
 	// from the textView.
-	scratch    []byte
+	scratch      []byte
-	blinkStart time.Time
+	eventKey     int
+	blinkStart   time.Time
+	focused      bool
+	requestFocus bool
 
 	// ime tracks the state relevant to input methods.
 	ime struct {
@@ -87,14 +89,16 @@ type Editor struct {
 
 	clicker gesture.Click
 
+	// events is the list of events not yet processed.
+	events []EditorEvent
+	// prevEvents is the number of events from the previous frame.
+	prevEvents int
 	// history contains undo history.
 	history []modification
 	// nextHistoryIdx is the index within the history of the next modification. This
 	// is only not len(history) immediately after undo operations occur. It is framed as the "next" value
 	// to make the zero value consistent.
 	nextHistoryIdx int
-
-	pending []EditorEvent
 }
 
 type offEntry struct {
@@ -187,37 +191,30 @@ const (
 	maxBlinkDuration = 10 * time.Second
 )
 
-func (e *Editor) processEvents(gtx layout.Context) (ev EditorEvent, ok bool) {
+// Events returns available editor events.
-	if len(e.pending) > 0 {
+func (e *Editor) Events() []EditorEvent {
-		out := e.pending[0]
+	events := e.events
-		e.pending = e.pending[:copy(e.pending, e.pending[1:])]
+	e.events = nil
-		return out, true
+	e.prevEvents = 0
-	}
+	return events
-	selStart, selEnd := e.Selection()
-	defer func() {
-		afterSelStart, afterSelEnd := e.Selection()
-		if selStart != afterSelStart || selEnd != afterSelEnd {
-			if ok {
-				e.pending = append(e.pending, SelectEvent{})
-			} else {
-				ev = SelectEvent{}
-				ok = true
-			}
-		}
-	}()
-
-	ev, ok = e.processPointer(gtx)
-	if ok {
-		return ev, ok
-	}
-	ev, ok = e.processKey(gtx)
-	if ok {
-		return ev, ok
-	}
-	return nil, false
 }
 
-func (e *Editor) processPointer(gtx layout.Context) (EditorEvent, bool) {
+func (e *Editor) processEvents(gtx layout.Context) {
+	// Flush events from before the previous Layout.
+	n := copy(e.events, e.events[e.prevEvents:])
+	e.events = e.events[:n]
+	e.prevEvents = n
+
+	oldStart, oldLen := min(e.text.Selection()), e.text.SelectionLen()
+	e.processPointer(gtx)
+	e.processKey(gtx)
+	// Queue a SelectEvent if the selection changed, including if it went away.
+	if newStart, newLen := min(e.text.Selection()), e.text.SelectionLen(); oldStart != newStart || oldLen != newLen {
+		e.events = append(e.events, SelectEvent{})
+	}
+}
+
+func (e *Editor) processPointer(gtx layout.Context) {
 	sbounds := e.text.ScrollBounds()
 	var smin, smax int
 	var axis gesture.Axis
@@ -228,19 +225,7 @@ func (e *Editor) processPointer(gtx layout.Context) (EditorEvent, bool) {
 		axis = gesture.Vertical
 		smin, smax = sbounds.Min.Y, sbounds.Max.Y
 	}
-	var scrollRange image.Rectangle
+	sdist := e.scroller.Update(gtx.Metric, gtx, gtx.Now, axis)
-	textDims := e.text.FullDimensions()
-	visibleDims := e.text.Dimensions()
-	if e.SingleLine {
-		scrollOffX := e.text.ScrollOff().X
-		scrollRange.Min.X = min(-scrollOffX, 0)
-		scrollRange.Max.X = max(0, textDims.Size.X-(scrollOffX+visibleDims.Size.X))
-	} else {
-		scrollOffY := e.text.ScrollOff().Y
-		scrollRange.Min.Y = -scrollOffY
-		scrollRange.Max.Y = max(0, textDims.Size.Y-(scrollOffY+visibleDims.Size.Y))
-	}
-	sdist := e.scroller.Update(gtx.Metric, gtx.Source, gtx.Now, axis, scrollRange)
 	var soff int
 	if e.SingleLine {
 		e.text.ScrollRel(sdist, 0)
@@ -249,173 +234,115 @@ func (e *Editor) processPointer(gtx layout.Context) (EditorEvent, bool) {
 		e.text.ScrollRel(0, sdist)
 		soff = e.text.ScrollOff().Y
 	}
-	for {
+	for _, evt := range e.clickDragEvents(gtx) {
-		evt, ok := e.clicker.Update(gtx.Source)
+		switch evt := evt.(type) {
-		if !ok {
+		case gesture.ClickEvent:
-			break
+			switch {
-		}
+			case evt.Kind == gesture.KindPress && evt.Source == pointer.Mouse,
-		ev, ok := e.processPointerEvent(gtx, evt)
+				evt.Kind == gesture.KindClick && evt.Source != pointer.Mouse:
-		if ok {
+				prevCaretPos, _ := e.text.Selection()
-			return ev, ok
+				e.blinkStart = gtx.Now
-		}
+				e.text.MoveCoord(image.Point{
-	}
+					X: int(math.Round(float64(evt.Position.X))),
-	for {
+					Y: int(math.Round(float64(evt.Position.Y))),
-		evt, ok := e.dragger.Update(gtx.Metric, gtx.Source, gesture.Both)
+				})
-		if !ok {
+				e.requestFocus = true
-			break
+				if e.scroller.State() != gesture.StateFlinging {
-		}
+					e.scrollCaret = true
-		ev, ok := e.processPointerEvent(gtx, evt)
+				}
-		if ok {
+
-			return ev, ok
+				if evt.Modifiers == key.ModShift {
+					start, end := e.text.Selection()
+					// If they clicked closer to the end, then change the end to
+					// where the caret used to be (effectively swapping start & end).
+					if abs(end-start) < abs(start-prevCaretPos) {
+						e.text.SetCaret(start, prevCaretPos)
+					}
+				} else {
+					e.text.ClearSelection()
+				}
+				e.dragging = true
+
+				// Process multi-clicks.
+				switch {
+				case evt.NumClicks == 2:
+					e.text.MoveWord(-1, selectionClear)
+					e.text.MoveWord(1, selectionExtend)
+					e.dragging = false
+				case evt.NumClicks >= 3:
+					e.text.MoveStart(selectionClear)
+					e.text.MoveEnd(selectionExtend)
+					e.dragging = false
+				}
+			}
+		case pointer.Event:
+			release := false
+			switch {
+			case evt.Kind == pointer.Release && evt.Source == pointer.Mouse:
+				release = true
+				fallthrough
+			case evt.Kind == pointer.Drag && evt.Source == pointer.Mouse:
+				if e.dragging {
+					e.blinkStart = gtx.Now
+					e.text.MoveCoord(image.Point{
+						X: int(math.Round(float64(evt.Position.X))),
+						Y: int(math.Round(float64(evt.Position.Y))),
+					})
+					e.scrollCaret = true
+
+					if release {
+						e.dragging = false
+					}
+				}
+			}
 		}
 	}
 
 	if (sdist > 0 && soff >= smax) || (sdist < 0 && soff <= smin) {
 		e.scroller.Stop()
 	}
-	return nil, false
 }
 
-func (e *Editor) processPointerEvent(gtx layout.Context, ev event.Event) (EditorEvent, bool) {
+func (e *Editor) clickDragEvents(gtx layout.Context) []event.Event {
-	switch evt := ev.(type) {
+	var combinedEvents []event.Event
-	case gesture.ClickEvent:
+	for _, evt := range e.clicker.Update(gtx) {
-		switch {
+		combinedEvents = append(combinedEvents, evt)
-		case evt.Kind == gesture.KindPress && evt.Source == pointer.Mouse,
-			evt.Kind == gesture.KindClick && evt.Source != pointer.Mouse:
-			prevCaretPos, _ := e.text.Selection()
-			e.blinkStart = gtx.Now
-			e.text.MoveCoord(image.Point{
-				X: int(math.Round(float64(evt.Position.X))),
-				Y: int(math.Round(float64(evt.Position.Y))),
-			})
-			gtx.Execute(key.FocusCmd{Tag: e})
-			if e.scroller.State() != gesture.StateFlinging {
-				e.scrollCaret = true
-			}
-
-			if evt.Modifiers == key.ModShift {
-				start, end := e.text.Selection()
-				// If they clicked closer to the end, then change the end to
-				// where the caret used to be (effectively swapping start & end).
-				if abs(end-start) < abs(start-prevCaretPos) {
-					e.text.SetCaret(start, prevCaretPos)
-				}
-			} else {
-				e.text.ClearSelection()
-			}
-			e.dragging = true
-
-			// Process multi-clicks.
-			switch {
-			case evt.NumClicks == 2:
-				e.text.MoveWord(-1, selectionClear)
-				e.text.MoveWord(1, selectionExtend)
-				e.dragging = false
-			case evt.NumClicks >= 3:
-				e.text.MoveStart(selectionClear)
-				e.text.MoveEnd(selectionExtend)
-				e.dragging = false
-			}
-		}
-	case pointer.Event:
-		release := false
-		switch {
-		case evt.Kind == pointer.Release && evt.Source == pointer.Mouse:
-			release = true
-			fallthrough
-		case evt.Kind == pointer.Drag && evt.Source == pointer.Mouse:
-			if e.dragging {
-				e.blinkStart = gtx.Now
-				e.text.MoveCoord(image.Point{
-					X: int(math.Round(float64(evt.Position.X))),
-					Y: int(math.Round(float64(evt.Position.Y))),
-				})
-				e.scrollCaret = true
-
-				if release {
-					e.dragging = false
-				}
-			}
-		}
 	}
-	return nil, false
+	for _, evt := range e.dragger.Update(gtx.Metric, gtx, gesture.Both) {
-}
+		combinedEvents = append(combinedEvents, evt)
-
-func condFilter(pred bool, f key.Filter) event.Filter {
-	if pred {
-		return f
-	} else {
-		return nil
 	}
+	return combinedEvents
 }
 
-func (e *Editor) processKey(gtx layout.Context) (EditorEvent, bool) {
+func (e *Editor) processKey(gtx layout.Context) {
 	if e.text.Changed() {
-		return ChangeEvent{}, true
+		e.events = append(e.events, ChangeEvent{})
-	}
-	caret, _ := e.text.Selection()
-	atBeginning := caret == 0
-	atEnd := caret == e.text.Len()
-	if gtx.Locale.Direction.Progression() != system.FromOrigin {
-		atEnd, atBeginning = atBeginning, atEnd
-	}
-	filters := []event.Filter{
-		key.FocusFilter{Target: e},
-		transfer.TargetFilter{Target: e, Type: "application/text"},
-		key.Filter{Focus: e, Name: key.NameEnter, Optional: key.ModShift},
-		key.Filter{Focus: e, Name: key.NameReturn, Optional: key.ModShift},
-
-		key.Filter{Focus: e, Name: "Z", Required: key.ModShortcut, Optional: key.ModShift},
-		key.Filter{Focus: e, Name: "C", Required: key.ModShortcut},
-		key.Filter{Focus: e, Name: "V", Required: key.ModShortcut},
-		key.Filter{Focus: e, Name: "X", Required: key.ModShortcut},
-		key.Filter{Focus: e, Name: "A", Required: key.ModShortcut},
-
-		key.Filter{Focus: e, Name: key.NameDeleteBackward, Optional: key.ModShortcutAlt | key.ModShift},
-		key.Filter{Focus: e, Name: key.NameDeleteForward, Optional: key.ModShortcutAlt | key.ModShift},
-
-		key.Filter{Focus: e, Name: key.NameHome, Optional: key.ModShift},
-		key.Filter{Focus: e, Name: key.NameEnd, Optional: key.ModShift},
-		key.Filter{Focus: e, Name: key.NamePageDown, Optional: key.ModShift},
-		key.Filter{Focus: e, Name: key.NamePageUp, Optional: key.ModShift},
-		condFilter(!atBeginning, key.Filter{Focus: e, Name: key.NameLeftArrow, Optional: key.ModShortcutAlt | key.ModShift}),
-		condFilter(!atBeginning, key.Filter{Focus: e, Name: key.NameUpArrow, Optional: key.ModShortcutAlt | key.ModShift}),
-		condFilter(!atEnd, key.Filter{Focus: e, Name: key.NameRightArrow, Optional: key.ModShortcutAlt | key.ModShift}),
-		condFilter(!atEnd, key.Filter{Focus: e, Name: key.NameDownArrow, Optional: key.ModShortcutAlt | key.ModShift}),
 	}
 	// adjust keeps track of runes dropped because of MaxLen.
 	var adjust int
-	for {
+	for _, ke := range gtx.Events(&e.eventKey) {
-		ke, ok := gtx.Event(filters...)
-		if !ok {
-			break
-		}
 		e.blinkStart = gtx.Now
 		switch ke := ke.(type) {
 		case key.FocusEvent:
+			e.focused = ke.Focus
 			// Reset IME state.
 			e.ime.imeState = imeState{}
-			if ke.Focus {
-				gtx.Execute(key.SoftKeyboardCmd{Show: true})
-			}
 		case key.Event:
-			if !gtx.Focused(e) || ke.State != key.Press {
+			if !e.focused || ke.State != key.Press {
 				break
 			}
 			if !e.ReadOnly && e.Submit && (ke.Name == key.NameReturn || ke.Name == key.NameEnter) {
 				if !ke.Modifiers.Contain(key.ModShift) {
 					e.scratch = e.text.Text(e.scratch)
-					return SubmitEvent{
+					e.events = append(e.events, SubmitEvent{
 						Text: string(e.scratch),
-					}, true
+					})
+					continue
 				}
 			}
+			e.command(gtx, ke)
 			e.scrollCaret = true
 			e.scroller.Stop()
-			ev, ok := e.command(gtx, ke)
-			if ok {
-				return ev, ok
-			}
 		case key.SnippetEvent:
 			e.updateSnippet(gtx, ke.Start, ke.End)
 		case key.EditEvent:
@@ -442,26 +369,19 @@ func (e *Editor) processKey(gtx layout.Context) (EditorEvent, bool) {
 			// Reset caret xoff.
 			e.text.MoveCaret(0, 0)
 			if submit {
-				e.scratch = e.text.Text(e.scratch)
-				submitEvent := SubmitEvent{
-					Text: string(e.scratch),
-				}
 				if e.text.Changed() {
-					e.pending = append(e.pending, submitEvent)
+					e.events = append(e.events, ChangeEvent{})
-					return ChangeEvent{}, true
 				}
-				return submitEvent, true
+				e.scratch = e.text.Text(e.scratch)
+				e.events = append(e.events, SubmitEvent{
+					Text: string(e.scratch),
+				})
 			}
 		// Complete a paste event, initiated by Shortcut-V in Editor.command().
-		case transfer.DataEvent:
+		case clipboard.Event:
 			e.scrollCaret = true
 			e.scroller.Stop()
-			content, err := io.ReadAll(ke.Open())
+			e.Insert(ke.Text)
-			if err == nil {
-				if e.Insert(string(content)) != 0 {
-					return ChangeEvent{}, true
-				}
-			}
 		case key.SelectionEvent:
 			e.scrollCaret = true
 			e.scroller.Stop()
@@ -472,12 +392,11 @@ func (e *Editor) processKey(gtx layout.Context) (EditorEvent, bool) {
 		}
 	}
 	if e.text.Changed() {
-		return ChangeEvent{}, true
+		e.events = append(e.events, ChangeEvent{})
 	}
-	return nil, false
 }
 
-func (e *Editor) command(gtx layout.Context, k key.Event) (EditorEvent, bool) {
+func (e *Editor) command(gtx layout.Context, k key.Event) {
 	direction := 1
 	if gtx.Locale.Direction.Progression() == system.TowardOrigin {
 		direction = -1
@@ -493,17 +412,15 @@ func (e *Editor) command(gtx layout.Context, k key.Event) (EditorEvent, bool) {
 		// half is in Editor.processKey() under clipboard.Event.
 		case "V":
 			if !e.ReadOnly {
-				gtx.Execute(clipboard.ReadCmd{Tag: e})
+				clipboard.ReadOp{Tag: &e.eventKey}.Add(gtx.Ops)
 			}
 		// Copy or Cut selection -- ignored if nothing selected.
 		case "C", "X":
 			e.scratch = e.text.SelectedText(e.scratch)
 			if text := string(e.scratch); text != "" {
-				gtx.Execute(clipboard.WriteCmd{Type: "application/text", Data: io.NopCloser(strings.NewReader(text))})
+				clipboard.WriteOp{Text: text}.Add(gtx.Ops)
 				if k.Name == "X" && !e.ReadOnly {
-					if e.Delete(1) != 0 {
+					e.Delete(1)
-						return ChangeEvent{}, true
-					}
 				}
 			}
 		// Select all
@@ -512,47 +429,33 @@ func (e *Editor) command(gtx layout.Context, k key.Event) (EditorEvent, bool) {
 		case "Z":
 			if !e.ReadOnly {
 				if k.Modifiers.Contain(key.ModShift) {
-					if ev, ok := e.redo(); ok {
+					e.redo()
-						return ev, ok
-					}
 				} else {
-					if ev, ok := e.undo(); ok {
+					e.undo()
-						return ev, ok
-					}
 				}
 			}
 		}
-		return nil, false
+		return
 	}
 	switch k.Name {
 	case key.NameReturn, key.NameEnter:
 		if !e.ReadOnly {
-			if e.Insert("\n") != 0 {
+			e.Insert("\n")
-				return ChangeEvent{}, true
-			}
 		}
 	case key.NameDeleteBackward:
 		if !e.ReadOnly {
 			if moveByWord {
-				if e.deleteWord(-1) != 0 {
+				e.deleteWord(-1)
-					return ChangeEvent{}, true
-				}
 			} else {
-				if e.Delete(-1) != 0 {
+				e.Delete(-1)
-					return ChangeEvent{}, true
-				}
 			}
 		}
 	case key.NameDeleteForward:
 		if !e.ReadOnly {
 			if moveByWord {
-				if e.deleteWord(1) != 0 {
+				e.deleteWord(1)
-					return ChangeEvent{}, true
-				}
 			} else {
-				if e.Delete(1) != 0 {
+				e.Delete(1)
-					return ChangeEvent{}, true
-				}
 			}
 		}
 	case key.NameUpArrow:
@@ -586,7 +489,16 @@ func (e *Editor) command(gtx layout.Context, k key.Event) (EditorEvent, bool) {
 	case key.NameEnd:
 		e.text.MoveEnd(selAct)
 	}
-	return nil, false
+}
+
+// Focus requests the input focus for the Editor.
+func (e *Editor) Focus() {
+	e.requestFocus = true
+}
+
+// Focused returns whether the editor is focused or not.
+func (e *Editor) Focused() bool {
+	return e.focused
 }
 
 // initBuffer should be invoked first in every exported function that accesses
@@ -605,51 +517,48 @@ func (e *Editor) initBuffer() {
 	e.text.WrapPolicy = e.WrapPolicy
 }
 
-// Update the state of the editor in response to input events. Update consumes editor
+// Update the state of the editor in response to input events.
-// input events until there are no remaining events or an editor event is generated.
+func (e *Editor) Update(gtx layout.Context) {
-// To fully update the state of the editor, callers should call Update until it returns
-// false.
-func (e *Editor) Update(gtx layout.Context) (EditorEvent, bool) {
 	e.initBuffer()
-	event, ok := e.processEvents(gtx)
+	e.processEvents(gtx)
-	// Notify IME of selection if it changed.
+	if e.focused {
-	newSel := e.ime.selection
+		// Notify IME of selection if it changed.
-	start, end := e.text.Selection()
+		newSel := e.ime.selection
-	newSel.rng = key.Range{
+		start, end := e.text.Selection()
-		Start: start,
+		newSel.rng = key.Range{
-		End:   end,
+			Start: start,
-	}
+			End:   end,
-	caretPos, carAsc, carDesc := e.text.CaretInfo()
+		}
-	newSel.caret = key.Caret{
+		caretPos, carAsc, carDesc := e.text.CaretInfo()
-		Pos:     layout.FPt(caretPos),
+		newSel.caret = key.Caret{
-		Ascent:  float32(carAsc),
+			Pos:     layout.FPt(caretPos),
-		Descent: float32(carDesc),
+			Ascent:  float32(carAsc),
-	}
+			Descent: float32(carDesc),
-	if newSel != e.ime.selection {
+		}
-		e.ime.selection = newSel
+		if newSel != e.ime.selection {
-		gtx.Execute(key.SelectionCmd{Tag: e, Range: newSel.rng, Caret: newSel.caret})
+			e.ime.selection = newSel
-	}
+			key.SelectionOp{
+				Tag:   &e.eventKey,
+				Range: newSel.rng,
+				Caret: newSel.caret,
+			}.Add(gtx.Ops)
+		}
 
-	e.updateSnippet(gtx, e.ime.start, e.ime.end)
+		e.updateSnippet(gtx, e.ime.start, e.ime.end)
-	return event, ok
+	}
 }
 
 // Layout lays out the editor using the provided textMaterial as the paint material
 // for the text glyphs+caret and the selectMaterial as the paint material for the
 // selection rectangle.
 func (e *Editor) Layout(gtx layout.Context, lt *text.Shaper, font font.Font, size unit.Sp, textMaterial, selectMaterial op.CallOp) layout.Dimensions {
-	for {
+	e.Update(gtx)
-		_, ok := e.Update(gtx)
-		if !ok {
-			break
-		}
-	}
 
 	e.text.Layout(gtx, lt, font, size)
 	return e.layout(gtx, textMaterial, selectMaterial)
 }
 
-// updateSnippet queues a key.SnippetCmd if the snippet content or position
+// updateSnippet adds a key.SnippetOp if the snippet content or position
 // have changed. off and len are in runes.
 func (e *Editor) updateSnippet(gtx layout.Context, start, end int) {
 	if start > end {
@@ -689,7 +598,10 @@ func (e *Editor) updateSnippet(gtx layout.Context, start, end int) {
 		return
 	}
 	e.ime.snippet = newSnip
-	gtx.Execute(key.SnippetCmd{Tag: e, Snippet: newSnip})
+	key.SnippetOp{
+		Tag:     &e.eventKey,
+		Snippet: newSnip,
+	}.Add(gtx.Ops)
 }
 
 func (e *Editor) layout(gtx layout.Context, textMaterial, selectMaterial op.CallOp) layout.Dimensions {
@@ -700,35 +612,79 @@ func (e *Editor) layout(gtx layout.Context, textMaterial, selectMaterial op.Call
 		e.scrollCaret = false
 		e.text.ScrollToCaret()
 	}
+	textDims := e.text.FullDimensions()
 	visibleDims := e.text.Dimensions()
 
 	defer clip.Rect(image.Rectangle{Max: visibleDims.Size}).Push(gtx.Ops).Pop()
 	pointer.CursorText.Add(gtx.Ops)
-	event.Op(gtx.Ops, e)
+	var keys key.Set
-	key.InputHintOp{Tag: e, Hint: e.InputHint}.Add(gtx.Ops)
+	if e.focused {
+		const keyFilterNoLeftUp = "(ShortAlt)-(Shift)-[→,↓]|(Shift)-[⏎,⌤]|(ShortAlt)-(Shift)-[⌫,⌦]|(Shift)-[⇞,⇟,⇱,⇲]|Short-[C,V,X,A]|Short-(Shift)-Z"
+		const keyFilterNoRightDown = "(ShortAlt)-(Shift)-[←,↑]|(Shift)-[⏎,⌤]|(ShortAlt)-(Shift)-[⌫,⌦]|(Shift)-[⇞,⇟,⇱,⇲]|Short-[C,V,X,A]|Short-(Shift)-Z"
+		const keyFilterNoArrows = "(Shift)-[⏎,⌤]|(ShortAlt)-(Shift)-[⌫,⌦]|(Shift)-[⇞,⇟,⇱,⇲]|Short-[C,V,X,A]|Short-(Shift)-Z"
+		const keyFilterAllArrows = "(ShortAlt)-(Shift)-[←,→,↑,↓]|(Shift)-[⏎,⌤]|(ShortAlt)-(Shift)-[⌫,⌦]|(Shift)-[⇞,⇟,⇱,⇲]|Short-[C,V,X,A]|Short-(Shift)-Z"
+		caret, _ := e.text.Selection()
+		switch {
+		case caret == 0 && caret == e.text.Len():
+			keys = keyFilterNoArrows
+		case caret == 0:
+			if gtx.Locale.Direction.Progression() == system.FromOrigin {
+				keys = keyFilterNoLeftUp
+			} else {
+				keys = keyFilterNoRightDown
+			}
+		case caret == e.text.Len():
+			if gtx.Locale.Direction.Progression() == system.FromOrigin {
+				keys = keyFilterNoRightDown
+			} else {
+				keys = keyFilterNoLeftUp
+			}
+		default:
+			keys = keyFilterAllArrows
+		}
+	}
+	key.InputOp{Tag: &e.eventKey, Hint: e.InputHint, Keys: keys}.Add(gtx.Ops)
+	if e.requestFocus {
+		key.FocusOp{Tag: &e.eventKey}.Add(gtx.Ops)
+		key.SoftKeyboardOp{Show: true}.Add(gtx.Ops)
+	}
+	e.requestFocus = false
 
-	e.scroller.Add(gtx.Ops)
+	var scrollRange image.Rectangle
+	if e.SingleLine {
+		scrollOffX := e.text.ScrollOff().X
+		scrollRange.Min.X = min(-scrollOffX, 0)
+		scrollRange.Max.X = max(0, textDims.Size.X-(scrollOffX+visibleDims.Size.X))
+	} else {
+		scrollOffY := e.text.ScrollOff().Y
+		scrollRange.Min.Y = -scrollOffY
+		scrollRange.Max.Y = max(0, textDims.Size.Y-(scrollOffY+visibleDims.Size.Y))
+	}
+	e.scroller.Add(gtx.Ops, scrollRange)
 
 	e.clicker.Add(gtx.Ops)
 	e.dragger.Add(gtx.Ops)
 	e.showCaret = false
-	if gtx.Focused(e) {
+	if e.focused {
 		now := gtx.Now
 		dt := now.Sub(e.blinkStart)
 		blinking := dt < maxBlinkDuration
 		const timePerBlink = time.Second / blinksPerSecond
 		nextBlink := now.Add(timePerBlink/2 - dt%(timePerBlink/2))
 		if blinking {
-			gtx.Execute(op.InvalidateCmd{At: nextBlink})
+			redraw := op.InvalidateOp{At: nextBlink}
+			redraw.Add(gtx.Ops)
 		}
-		e.showCaret = !blinking || dt%timePerBlink < timePerBlink/2
+		e.showCaret = e.focused && (!blinking || dt%timePerBlink < timePerBlink/2)
 	}
+	disabled := gtx.Queue == nil
+
 	semantic.Editor.Add(gtx.Ops)
 	if e.Len() > 0 {
 		e.paintSelection(gtx, selectMaterial)
 		e.paintText(gtx, textMaterial)
 	}
-	if gtx.Enabled() {
+	if !disabled {
 		e.paintCaret(gtx, textMaterial)
 	}
 	return visibleDims
@@ -738,7 +694,7 @@ func (e *Editor) layout(gtx layout.Context, textMaterial, selectMaterial op.Call
 // material to set the painting material for the selection.
 func (e *Editor) paintSelection(gtx layout.Context, material op.CallOp) {
 	e.initBuffer()
-	if !gtx.Focused(e) {
+	if !e.focused {
 		return
 	}
 	e.text.PaintSelection(gtx, material)
@@ -802,10 +758,10 @@ func (e *Editor) CaretCoords() f32.Point {
 //
 // If there is a selection, it is deleted and counts as a single grapheme
 // cluster.
-func (e *Editor) Delete(graphemeClusters int) (deletedRunes int) {
+func (e *Editor) Delete(graphemeClusters int) {
 	e.initBuffer()
 	if graphemeClusters == 0 {
-		return 0
+		return
 	}
 
 	start, end := e.text.Selection()
@@ -821,10 +777,9 @@ func (e *Editor) Delete(graphemeClusters int) (deletedRunes int) {
 	// Reset xoff.
 	e.text.MoveCaret(0, 0)
 	e.ClearSelection()
-	return end - start
 }
 
-func (e *Editor) Insert(s string) (insertedRunes int) {
+func (e *Editor) Insert(s string) {
 	e.initBuffer()
 	if e.SingleLine {
 		s = strings.ReplaceAll(s, "\n", " ")
@@ -838,7 +793,6 @@ func (e *Editor) Insert(s string) (insertedRunes int) {
 	e.text.MoveCaret(0, 0)
 	e.SetCaret(start+moves, start+moves)
 	e.scrollCaret = true
-	return moves
 }
 
 // modification represents a change to the contents of the editor buffer.
@@ -858,10 +812,10 @@ type modification struct {
 
 // undo applies the modification at e.history[e.historyIdx] and decrements
 // e.historyIdx.
-func (e *Editor) undo() (EditorEvent, bool) {
+func (e *Editor) undo() {
 	e.initBuffer()
 	if len(e.history) < 1 || e.nextHistoryIdx == 0 {
-		return nil, false
+		return
 	}
 	mod := e.history[e.nextHistoryIdx-1]
 	replaceEnd := mod.StartRune + utf8.RuneCountInString(mod.ApplyContent)
@@ -869,15 +823,14 @@ func (e *Editor) undo() (EditorEvent, bool) {
 	caretEnd := mod.StartRune + utf8.RuneCountInString(mod.ReverseContent)
 	e.SetCaret(caretEnd, mod.StartRune)
 	e.nextHistoryIdx--
-	return ChangeEvent{}, true
 }
 
 // redo applies the modification at e.history[e.historyIdx] and increments
 // e.historyIdx.
-func (e *Editor) redo() (EditorEvent, bool) {
+func (e *Editor) redo() {
 	e.initBuffer()
 	if len(e.history) < 1 || e.nextHistoryIdx == len(e.history) {
-		return nil, false
+		return
 	}
 	mod := e.history[e.nextHistoryIdx]
 	end := mod.StartRune + utf8.RuneCountInString(mod.ReverseContent)
@@ -885,7 +838,6 @@ func (e *Editor) redo() (EditorEvent, bool) {
 	caretEnd := mod.StartRune + utf8.RuneCountInString(mod.ApplyContent)
 	e.SetCaret(caretEnd, mod.StartRune)
 	e.nextHistoryIdx++
-	return ChangeEvent{}, true
 }
 
 // replace the text between start and end with s. Indices are in runes.
@@ -969,18 +921,18 @@ func (e *Editor) MoveCaret(startDelta, endDelta int) {
 // Positive is forward, negative is backward.
 // Absolute values greater than one will delete that many words.
 // The selection counts as a single word.
-func (e *Editor) deleteWord(distance int) (deletedRunes int) {
+func (e *Editor) deleteWord(distance int) {
 	if distance == 0 {
 		return
 	}
 
 	start, end := e.text.Selection()
 	if start != end {
-		deletedRunes = e.Delete(1)
+		e.Delete(1)
 		distance -= sign(distance)
 	}
 	if distance == 0 {
-		return deletedRunes
+		return
 	}
 
 	// split the distance information into constituent parts to be
@@ -1020,8 +972,7 @@ func (e *Editor) deleteWord(distance int) (deletedRunes int) {
 			runes += 1
 		}
 	}
-	deletedRunes += e.Delete(runes * direction)
+	e.Delete(runes * direction)
-	return deletedRunes
 }
 
 // SelectionLen returns the length of the selection, in runes; it is

widget/editor_test.go

@@ -20,7 +20,7 @@ import (
 	"gioui.org/font"
 	"gioui.org/font/gofont"
 	"gioui.org/font/opentype"
-	"gioui.org/io/input"
+	"gioui.org/io/event"
 	"gioui.org/io/key"
 	"gioui.org/io/pointer"
 	"gioui.org/io/system"
@@ -96,14 +96,17 @@ func assertContents(t *testing.T, e *Editor, contents string, selectionStart, se
 // TestEditorReadOnly ensures that mouse and keyboard interactions with readonly
 // editors do nothing but manipulate the text selection.
 func TestEditorReadOnly(t *testing.T) {
-	r := new(input.Router)
 	gtx := layout.Context{
 		Ops: new(op.Ops),
 		Constraints: layout.Constraints{
 			Max: image.Pt(100, 100),
 		},
 		Locale: english,
-		Source: r.Source(),
+	}
+	gtx.Queue = &testQueue{
+		events: []event.Event{
+			key.FocusEvent{Focus: true},
+		},
 	}
 	cache := text.NewShaper(text.NoSystemFonts(), text.WithCollection(gofont.Collection()))
 	fontSize := unit.Sp(10)
@@ -115,23 +118,12 @@ func TestEditorReadOnly(t *testing.T) {
 	if cStart != cEnd {
 		t.Errorf("unexpected initial caret positions")
 	}
-	gtx.Execute(key.FocusCmd{Tag: e})
+	e.Layout(gtx, cache, font, fontSize, op.CallOp{}, op.CallOp{})
-	layoutEditor := func() layout.Dimensions {
-		return e.Layout(gtx, cache, font, fontSize, op.CallOp{}, op.CallOp{})
-	}
-	layoutEditor()
-	r.Frame(gtx.Ops)
-	gtx.Ops.Reset()
-	layoutEditor()
-	r.Frame(gtx.Ops)
-	gtx.Ops.Reset()
-	layoutEditor()
-	r.Frame(gtx.Ops)
 
 	// Select everything.
 	gtx.Ops.Reset()
-	r.Queue(key.Event{Name: "A", Modifiers: key.ModShortcut})
+	gtx.Queue = &testQueue{events: []event.Event{key.Event{Name: "A", Modifiers: key.ModShortcut}}}
-	layoutEditor()
+	e.Layout(gtx, cache, font, fontSize, op.CallOp{}, op.CallOp{})
 	textContent := e.Text()
 	cStart2, cEnd2 := e.Selection()
 	if cStart2 > cEnd2 {
@@ -146,7 +138,7 @@ func TestEditorReadOnly(t *testing.T) {
 
 	// Type some new characters.
 	gtx.Ops.Reset()
-	r.Queue(key.EditEvent{Range: key.Range{Start: cStart2, End: cEnd2}, Text: "something else"})
+	gtx.Queue = &testQueue{events: []event.Event{key.EditEvent{Range: key.Range{Start: cStart2, End: cEnd2}, Text: "something else"}}}
 	e.Update(gtx)
 	textContent2 := e.Text()
 	if textContent2 != textContent {
@@ -155,8 +147,8 @@ func TestEditorReadOnly(t *testing.T) {
 
 	// Try to delete selection.
 	gtx.Ops.Reset()
-	r.Queue(key.Event{Name: key.NameDeleteBackward})
+	gtx.Queue = &testQueue{events: []event.Event{key.Event{Name: key.NameDeleteBackward}}}
-	dims := layoutEditor()
+	dims := e.Layout(gtx, cache, font, fontSize, op.CallOp{}, op.CallOp{})
 	textContent2 = e.Text()
 	if textContent2 != textContent {
 		t.Errorf("readonly editor modified by delete key.Event")
@@ -165,14 +157,14 @@ func TestEditorReadOnly(t *testing.T) {
 	// Click and drag from the middle of the first line
 	// to the center.
 	gtx.Ops.Reset()
-	r.Queue(
+	gtx.Queue = &testQueue{events: []event.Event{
 		pointer.Event{
 			Kind:     pointer.Press,
 			Buttons:  pointer.ButtonPrimary,
 			Position: f32.Pt(float32(dims.Size.X)*.5, 5),
 		},
 		pointer.Event{
-			Kind:     pointer.Move,
+			Kind:     pointer.Drag,
 			Buttons:  pointer.ButtonPrimary,
 			Position: layout.FPt(dims.Size).Mul(.5),
 		},
@@ -181,7 +173,7 @@ func TestEditorReadOnly(t *testing.T) {
 			Buttons:  pointer.ButtonPrimary,
 			Position: layout.FPt(dims.Size).Mul(.5),
 		},
-	)
+	}}
 	e.Update(gtx)
 	cStart3, cEnd3 := e.Selection()
 	if cStart3 == cStart2 || cEnd3 == cEnd2 {
@@ -504,22 +496,22 @@ func TestEditorLigature(t *testing.T) {
 
 func TestEditorDimensions(t *testing.T) {
 	e := new(Editor)
-	r := new(input.Router)
+	tq := &testQueue{
+		events: []event.Event{
+			key.EditEvent{Text: "A"},
+		},
+	}
 	gtx := layout.Context{
 		Ops:         new(op.Ops),
 		Constraints: layout.Constraints{Max: image.Pt(100, 100)},
-		Source:      r.Source(),
+		Queue:       tq,
 		Locale:      english,
 	}
 	cache := text.NewShaper(text.NoSystemFonts(), text.WithCollection(gofont.Collection()))
 	fontSize := unit.Sp(10)
 	font := font.Font{}
-	gtx.Execute(key.FocusCmd{Tag: e})
-	e.Layout(gtx, cache, font, fontSize, op.CallOp{}, op.CallOp{})
-	r.Frame(gtx.Ops)
-	r.Queue(key.EditEvent{Text: "A"})
 	dims := e.Layout(gtx, cache, font, fontSize, op.CallOp{}, op.CallOp{})
-	if dims.Size.X < 5 {
+	if dims.Size.X == 0 {
 		t.Errorf("EditEvent was not reflected in Editor width")
 	}
 }
@@ -890,11 +882,9 @@ f 2 4 6 8 f
 g 2 4 6 8 g
 `)
 
-	r := new(input.Router)
 	gtx := layout.Context{
 		Ops:    new(op.Ops),
 		Locale: english,
-		Source: r.Source(),
 	}
 	cache := text.NewShaper(text.NoSystemFonts(), text.WithCollection(gofont.Collection()))
 	font := font.Font{}
@@ -902,39 +892,42 @@ g 2 4 6 8 g
 
 	var tim time.Duration
 	selected := func(start, end int) string {
-		gtx.Execute(key.FocusCmd{Tag: e})
 		// Layout once with no events; populate e.lines.
+		gtx.Queue = nil
 		e.Layout(gtx, cache, font, fontSize, op.CallOp{}, op.CallOp{})
+		_ = e.Events() // throw away any events from this layout
 
-		r.Frame(gtx.Ops)
-		gtx.Source = r.Source()
 		// Build the selection events
 		startPos := e.text.closestToRune(start)
 		endPos := e.text.closestToRune(end)
-		r.Queue(
+		tq := &testQueue{
-			pointer.Event{
+			events: []event.Event{
-				Buttons:  pointer.ButtonPrimary,
+				pointer.Event{
-				Kind:     pointer.Press,
+					Buttons:  pointer.ButtonPrimary,
-				Source:   pointer.Mouse,
+					Kind:     pointer.Press,
-				Time:     tim,
+					Source:   pointer.Mouse,
-				Position: f32.Pt(textWidth(e, startPos.lineCol.line, 0, startPos.lineCol.col), textBaseline(e, startPos.lineCol.line)),
+					Time:     tim,
+					Position: f32.Pt(textWidth(e, startPos.lineCol.line, 0, startPos.lineCol.col), textBaseline(e, startPos.lineCol.line)),
+				},
+				pointer.Event{
+					Kind:     pointer.Release,
+					Source:   pointer.Mouse,
+					Time:     tim,
+					Position: f32.Pt(textWidth(e, endPos.lineCol.line, 0, endPos.lineCol.col), textBaseline(e, endPos.lineCol.line)),
+				},
 			},
-			pointer.Event{
+		}
-				Kind:     pointer.Release,
-				Source:   pointer.Mouse,
-				Time:     tim,
-				Position: f32.Pt(textWidth(e, endPos.lineCol.line, 0, endPos.lineCol.col), textBaseline(e, endPos.lineCol.line)),
-			},
-		)
 		tim += time.Second // Avoid multi-clicks.
+		gtx.Queue = tq
 
-		for {
+		e.Layout(gtx, cache, font, fontSize, op.CallOp{}, op.CallOp{})
-			_, ok := e.Update(gtx) // throw away any events from this layout
+		for _, evt := range e.Events() {
-			if !ok {
+			switch evt.(type) {
-				break
+			case SelectEvent:
+				return e.SelectedText()
 			}
 		}
-		return e.SelectedText()
+		return ""
 	}
 	type screenPos image.Point
 	logicalPosMatch := func(t *testing.T, n int, label string, expected screenPos, actual combinedPos) {
@@ -972,7 +965,7 @@ g 2 4 6 8 g
 		// Constrain the editor to roughly 6 columns wide and redraw
 		gtx.Constraints = layout.Exact(image.Pt(36, 36))
 		// Keep existing selection
-		gtx = gtx.Disabled()
+		gtx.Queue = nil
 		e.Layout(gtx, cache, font, fontSize, op.CallOp{}, op.CallOp{})
 
 		caretStart := e.text.closestToRune(e.text.caret.start)
@@ -987,30 +980,19 @@ func TestSelectMove(t *testing.T) {
 	e := new(Editor)
 	e.SetText(`0123456789`)
 
-	r := new(input.Router)
 	gtx := layout.Context{
 		Ops:    new(op.Ops),
 		Locale: english,
-		Source: r.Source(),
 	}
 	cache := text.NewShaper(text.NoSystemFonts(), text.WithCollection(gofont.Collection()))
 	font := font.Font{}
 	fontSize := unit.Sp(10)
 
 	// Layout once to populate e.lines and get focus.
-	gtx.Execute(key.FocusCmd{Tag: e})
+	gtx.Queue = newQueue(key.FocusEvent{Focus: true})
 	e.Layout(gtx, cache, font, fontSize, op.CallOp{}, op.CallOp{})
-	r.Frame(gtx.Ops)
-	// Set up selecton so the Editor key handler filters for all 4 directional keys.
-	e.SetCaret(3, 6)
-	gtx.Ops.Reset()
-	e.Layout(gtx, cache, font, fontSize, op.CallOp{}, op.CallOp{})
-	r.Frame(gtx.Ops)
-	gtx.Ops.Reset()
-	e.Layout(gtx, cache, font, fontSize, op.CallOp{}, op.CallOp{})
-	r.Frame(gtx.Ops)
 
-	for _, keyName := range []key.Name{key.NameLeftArrow, key.NameRightArrow, key.NameUpArrow, key.NameDownArrow} {
+	testKey := func(keyName string) {
 		// Select 345
 		e.SetCaret(3, 6)
 		if expected, got := "345", e.SelectedText(); expected != got {
@@ -1018,15 +1000,18 @@ func TestSelectMove(t *testing.T) {
 		}
 
 		// Press the key
-		r.Queue(key.Event{State: key.Press, Name: keyName})
+		gtx.Queue = newQueue(key.Event{State: key.Press, Name: keyName})
-		gtx.Ops.Reset()
 		e.Layout(gtx, cache, font, fontSize, op.CallOp{}, op.CallOp{})
-		r.Frame(gtx.Ops)
 
 		if expected, got := "", e.SelectedText(); expected != got {
 			t.Errorf("KeyName %s, expected %q, got %q", keyName, expected, got)
 		}
 	}
+
+	testKey(key.NameLeftArrow)
+	testKey(key.NameRightArrow)
+	testKey(key.NameUpArrow)
+	testKey(key.NameDownArrow)
 }
 
 func TestEditor_Read(t *testing.T) {
@@ -1079,22 +1064,17 @@ func TestEditor_MaxLen(t *testing.T) {
 	}
 
 	e.SetText("2345678")
-	r := new(input.Router)
 	gtx := layout.Context{
 		Ops:         new(op.Ops),
 		Constraints: layout.Exact(image.Pt(100, 100)),
-		Source:      r.Source(),
+		Queue: newQueue(
+			key.EditEvent{Range: key.Range{Start: 0, End: 2}, Text: "1234"},
+			key.SelectionEvent{Start: 4, End: 4},
+		),
 	}
 	cache := text.NewShaper(text.NoSystemFonts(), text.WithCollection(gofont.Collection()))
 	fontSize := unit.Sp(10)
 	font := font.Font{}
-	gtx.Execute(key.FocusCmd{Tag: e})
-	e.Layout(gtx, cache, font, fontSize, op.CallOp{}, op.CallOp{})
-	r.Frame(gtx.Ops)
-	r.Queue(
-		key.EditEvent{Range: key.Range{Start: 0, End: 2}, Text: "1234"},
-		key.SelectionEvent{Start: 4, End: 4},
-	)
 	e.Layout(gtx, cache, font, fontSize, op.CallOp{}, op.CallOp{})
 
 	if got, want := e.Text(), "12345678"; got != want {
@@ -1115,22 +1095,17 @@ func TestEditor_Filter(t *testing.T) {
 	}
 
 	e.SetText("2345678")
-	r := new(input.Router)
 	gtx := layout.Context{
 		Ops:         new(op.Ops),
 		Constraints: layout.Exact(image.Pt(100, 100)),
-		Source:      r.Source(),
+		Queue: newQueue(
+			key.EditEvent{Range: key.Range{Start: 0, End: 0}, Text: "ab1"},
+			key.SelectionEvent{Start: 4, End: 4},
+		),
 	}
 	cache := text.NewShaper(text.NoSystemFonts(), text.WithCollection(gofont.Collection()))
 	fontSize := unit.Sp(10)
 	font := font.Font{}
-	gtx.Execute(key.FocusCmd{Tag: e})
-	e.Layout(gtx, cache, font, fontSize, op.CallOp{}, op.CallOp{})
-	r.Frame(gtx.Ops)
-	r.Queue(
-		key.EditEvent{Range: key.Range{Start: 0, End: 0}, Text: "ab1"},
-		key.SelectionEvent{Start: 4, End: 4},
-	)
 	e.Layout(gtx, cache, font, fontSize, op.CallOp{}, op.CallOp{})
 
 	if got, want := e.Text(), "12345678"; got != want {
@@ -1145,33 +1120,22 @@ func TestEditor_Submit(t *testing.T) {
 	e := new(Editor)
 	e.Submit = true
 
-	r := new(input.Router)
 	gtx := layout.Context{
 		Ops:         new(op.Ops),
 		Constraints: layout.Exact(image.Pt(100, 100)),
-		Source:      r.Source(),
+		Queue: newQueue(
+			key.EditEvent{Range: key.Range{Start: 0, End: 0}, Text: "ab1\n"},
+		),
 	}
 	cache := text.NewShaper(text.NoSystemFonts(), text.WithCollection(gofont.Collection()))
 	fontSize := unit.Sp(10)
 	font := font.Font{}
-	gtx.Execute(key.FocusCmd{Tag: e})
 	e.Layout(gtx, cache, font, fontSize, op.CallOp{}, op.CallOp{})
-	r.Frame(gtx.Ops)
-	r.Queue(
-		key.EditEvent{Range: key.Range{Start: 0, End: 0}, Text: "ab1\n"},
-	)
 
-	got := []EditorEvent{}
-	for {
-		ev, ok := e.Update(gtx)
-		if !ok {
-			break
-		}
-		got = append(got, ev)
-	}
 	if got, want := e.Text(), "ab1"; got != want {
 		t.Errorf("editor failed to filter newline")
 	}
+	got := e.Events()
 	want := []EditorEvent{
 		ChangeEvent{},
 		SubmitEvent{Text: e.Text()},
@@ -1181,29 +1145,6 @@ func TestEditor_Submit(t *testing.T) {
 	}
 }
 
-func TestNoFilterAllocs(t *testing.T) {
-	b := testing.Benchmark(func(b *testing.B) {
-		r := new(input.Router)
-		e := new(Editor)
-		gtx := layout.Context{
-			Ops: new(op.Ops),
-			Constraints: layout.Constraints{
-				Max: image.Pt(100, 100),
-			},
-			Locale: english,
-			Source: r.Source(),
-		}
-		b.ReportAllocs()
-		b.ResetTimer()
-		for i := 0; i < b.N; i++ {
-			e.Update(gtx)
-		}
-	})
-	if allocs := b.AllocsPerOp(); allocs != 0 {
-		t.Fatalf("expected 0 AllocsPerOp, got %d", allocs)
-	}
-}
-
 // textWidth is a text helper for building simple selection events.
 // It assumes single-run lines, which isn't safe with non-test text
 // data.
@@ -1223,3 +1164,15 @@ func textBaseline(e *Editor, lineNum int) float32 {
 	start := e.text.closestToLineCol(lineNum, 0)
 	return float32(start.y)
 }
+
+type testQueue struct {
+	events []event.Event
+}
+
+func newQueue(e ...event.Event) *testQueue {
+	return &testQueue{events: e}
+}
+
+func (q *testQueue) Events(_ event.Tag) []event.Event {
+	return q.events
+}

widget/enum.go

@@ -4,7 +4,6 @@ package widget
 
 import (
 	"gioui.org/gesture"
-	"gioui.org/io/event"
 	"gioui.org/io/key"
 	"gioui.org/io/pointer"
 	"gioui.org/io/semantic"
@@ -41,21 +40,17 @@ func (e *Enum) index(k string) *enumKey {
 
 // Update the state and report whether Value has changed by user interaction.
 func (e *Enum) Update(gtx layout.Context) bool {
-	if !gtx.Enabled() {
+	if gtx.Queue == nil {
 		e.focused = false
 	}
 	e.hovering = false
 	changed := false
 	for _, state := range e.keys {
-		for {
+		for _, ev := range state.click.Update(gtx) {
-			ev, ok := state.click.Update(gtx.Source)
-			if !ok {
-				break
-			}
 			switch ev.Kind {
 			case gesture.KindPress:
 				if ev.Source == pointer.Mouse {
-					gtx.Execute(key.FocusCmd{Tag: &state.tag})
+					key.FocusOp{Tag: &state.tag}.Add(gtx.Ops)
 				}
 			case gesture.KindClick:
 				if state.key != e.Value {
@@ -64,15 +59,7 @@ func (e *Enum) Update(gtx layout.Context) bool {
 				}
 			}
 		}
-		for {
+		for _, ev := range gtx.Events(&state.tag) {
-			ev, ok := gtx.Event(
-				key.FocusFilter{Target: &state.tag},
-				key.Filter{Focus: &state.tag, Name: key.NameReturn},
-				key.Filter{Focus: &state.tag, Name: key.NameSpace},
-			)
-			if !ok {
-				break
-			}
 			switch ev := ev.(type) {
 			case key.FocusEvent:
 				if ev.Focus {
@@ -82,7 +69,7 @@ func (e *Enum) Update(gtx layout.Context) bool {
 					e.focused = false
 				}
 			case key.Event:
-				if ev.State != key.Release {
+				if !e.focused || ev.State != key.Release {
 					break
 				}
 				if ev.Name != key.NameReturn && ev.Name != key.NameSpace {
@@ -130,9 +117,12 @@ func (e *Enum) Layout(gtx layout.Context, k string, content layout.Widget) layou
 	}
 	clk := &state.click
 	clk.Add(gtx.Ops)
-	event.Op(gtx.Ops, &state.tag)
+	enabled := gtx.Queue != nil
+	if enabled {
+		key.InputOp{Tag: &state.tag, Keys: "⏎|Space"}.Add(gtx.Ops)
+	}
 	semantic.SelectedOp(k == e.Value).Add(gtx.Ops)
-	semantic.EnabledOp(gtx.Enabled()).Add(gtx.Ops)
+	semantic.EnabledOp(enabled).Add(gtx.Ops)
 	c.Add(gtx.Ops)
 
 	return dims

widget/example_test.go

@@ -5,13 +5,10 @@ package widget_test
 import (
 	"fmt"
 	"image"
-	"io"
-	"strings"
 
 	"gioui.org/f32"
-	"gioui.org/io/event"
-	"gioui.org/io/input"
 	"gioui.org/io/pointer"
+	"gioui.org/io/router"
 	"gioui.org/io/transfer"
 	"gioui.org/layout"
 	"gioui.org/op"
@@ -24,11 +21,11 @@ func ExampleClickable_passthrough() {
 	// pointer events can be passed down for the underlying
 	// widgets to pick them up.
 	var button1, button2 widget.Clickable
-	var r input.Router
+	var r router.Router
 	gtx := layout.Context{
 		Ops:         new(op.Ops),
 		Constraints: layout.Exact(image.Pt(100, 100)),
-		Source:      r.Source(),
+		Queue:       &r,
 	}
 
 	// widget lays out two buttons on top of each other.
@@ -74,15 +71,15 @@ func ExampleClickable_passthrough() {
 }
 
 func ExampleDraggable_Layout() {
-	var r input.Router
+	var r router.Router
 	gtx := layout.Context{
 		Ops:         new(op.Ops),
 		Constraints: layout.Exact(image.Pt(100, 100)),
-		Source:      r.Source(),
+		Queue:       &r,
 	}
 	// mime is the type used to match drag and drop operations.
 	// It could be left empty in this example.
-	const mime = "MyMime"
+	mime := "MyMime"
 	drag := &widget.Draggable{Type: mime}
 	var drop int
 	// widget lays out the drag and drop handlers and processes
@@ -97,7 +94,7 @@ func ExampleDraggable_Layout() {
 		// drag must respond with an Offer event when requested.
 		// Use the drag method for this.
 		if m, ok := drag.Update(gtx); ok {
-			drag.Offer(gtx, m, io.NopCloser(strings.NewReader("hello world")))
+			drag.Offer(gtx.Ops, m, offer{Data: "hello world"})
 		}
 
 		// Setup the area for drops.
@@ -105,21 +102,17 @@ func ExampleDraggable_Layout() {
 			Min: image.Pt(20, 20),
 			Max: image.Pt(40, 40),
 		}.Push(gtx.Ops)
-		event.Op(gtx.Ops, &drop)
+		transfer.TargetOp{
+			Tag:  &drop,
+			Type: mime, // this must match the drag Type for the drop to succeed
+		}.Add(gtx.Ops)
 		ds.Pop()
-
 		// Check for the received data.
-		for {
+		for _, ev := range gtx.Events(&drop) {
-			ev, ok := gtx.Event(transfer.TargetFilter{Target: &drop, Type: mime})
-			if !ok {
-				break
-			}
 			switch e := ev.(type) {
 			case transfer.DataEvent:
 				data := e.Open()
-				defer data.Close()
+				fmt.Println(data.(offer).Data)
-				content, _ := io.ReadAll(data)
-				fmt.Println(string(content))
 			}
 		}
 	}
@@ -152,3 +145,10 @@ func ExampleDraggable_Layout() {
 	// Output:
 	// hello world
 }
+
+type offer struct {
+	Data string
+}
+
+func (offer) Read([]byte) (int, error) { return 0, nil }
+func (offer) Close() error             { return nil }

widget/float.go

@@ -48,11 +48,7 @@ func (f *Float) Layout(gtx layout.Context, axis layout.Axis, pointerMargin unit.
 // The range of f is set by the minimum constraints main axis value.
 func (f *Float) Update(gtx layout.Context) bool {
 	changed := false
-	for {
+	for _, e := range f.drag.Update(gtx.Metric, gtx, gesture.Axis(f.axis)) {
-		e, ok := f.drag.Update(gtx.Metric, gtx.Source, gesture.Axis(f.axis))
-		if !ok {
-			break
-		}
 		if f.length > 0 && (e.Kind == pointer.Press || e.Kind == pointer.Drag) {
 			pos := e.Position.X
 			if f.axis == layout.Vertical {

widget/index.go

@@ -347,6 +347,10 @@ type Region struct {
 	Baseline int
 }
 
+// region is identical to Region except that its coordinates are in document
+// space instead of a widget coordinate space.
+type region = Region
+
 // locate returns highlight regions covering the glyphs that represent the runes in
 // [startRune,endRune). If the rects parameter is non-nil, locate will use it to
 // return results instead of allocating, provided that there is enough capacity.

widget/label.go

@@ -97,6 +97,10 @@ func (l Label) LayoutDetailed(gtx layout.Context, lt *text.Shaper, font font.Fon
 	return dims, TextInfo{Truncated: it.truncated}
 }
 
+func r2p(r clip.Rect) clip.Op {
+	return clip.Stroke{Path: r.Path(), Width: 1}.Op()
+}
+
 // textIterator computes the bounding box of and paints text.
 type textIterator struct {
 	// viewport is the rectangle of document coordinates that the iterator is

widget/list.go

@@ -29,8 +29,8 @@ type Scrollbar struct {
 	oldDragPos float32
 }
 
-// Update updates the internal state of the scrollbar based on events
+// Layout updates the internal state of the scrollbar based on events
-// since the previous call to Update. The provided axis will be used to
+// since the previous call to Layout. The provided axis will be used to
 // normalize input event coordinates and constraints into an axis-
 // independent format. viewportStart is the position of the beginning
 // of the scrollable viewport relative to the underlying content expressed
@@ -39,7 +39,7 @@ type Scrollbar struct {
 // as a value in the range [0,1]. For example, if viewportStart is 0.25
 // and viewportEnd is .5, the viewport described by the scrollbar is
 // currently showing the second quarter of the underlying content.
-func (s *Scrollbar) Update(gtx layout.Context, axis layout.Axis, viewportStart, viewportEnd float32) {
+func (s *Scrollbar) Layout(gtx layout.Context, axis layout.Axis, viewportStart, viewportEnd float32) layout.Dimensions {
 	// Calculate the length of the major axis of the scrollbar. This is
 	// the length of the track within which pointer events occur, and is
 	// used to scale those interactions.
@@ -61,11 +61,7 @@ func (s *Scrollbar) Update(gtx layout.Context, axis layout.Axis, viewportStart,
 	}
 
 	// Jump to a click in the track.
-	for {
+	for _, event := range s.track.Update(gtx) {
-		event, ok := s.track.Update(gtx.Source)
-		if !ok {
-			break
-		}
 		if event.Kind != gesture.KindClick ||
 			event.Modifiers != key.Modifiers(0) ||
 			event.NumClicks > 1 {
@@ -84,11 +80,7 @@ func (s *Scrollbar) Update(gtx layout.Context, axis layout.Axis, viewportStart,
 	}
 
 	// Offset to account for any drags.
-	for {
+	for _, event := range s.drag.Update(gtx.Metric, gtx, gesture.Axis(axis)) {
-		event, ok := s.drag.Update(gtx.Metric, gtx.Source, gesture.Axis(axis))
-		if !ok {
-			break
-		}
 		switch event.Kind {
 		case pointer.Drag:
 		case pointer.Release, pointer.Cancel:
@@ -144,11 +136,9 @@ func (s *Scrollbar) Update(gtx layout.Context, axis layout.Axis, viewportStart,
 
 	// Process events from the indicator so that hover is
 	// detected properly.
-	for {
+	_ = s.indicator.Update(gtx)
-		if _, ok := s.indicator.Update(gtx.Source); !ok {
+
-			break
+	return layout.Dimensions{}
-		}
-	}
 }
 
 // AddTrack configures the track click listener for the scrollbar to use

widget/material/button.go

@@ -96,7 +96,7 @@ func Clickable(gtx layout.Context, button *widget.Clickable, w layout.Widget) la
 		return layout.Background{}.Layout(gtx,
 			func(gtx layout.Context) layout.Dimensions {
 				defer clip.Rect{Max: gtx.Constraints.Min}.Push(gtx.Ops).Pop()
-				if button.Hovered() || gtx.Focused(button) {
+				if button.Hovered() || button.Focused() {
 					paint.Fill(gtx.Ops, f32color.Hovered(color.NRGBA{}))
 				}
 				for _, c := range button.History() {
@@ -133,9 +133,9 @@ func (b ButtonLayoutStyle) Layout(gtx layout.Context, w layout.Widget) layout.Di
 				defer clip.UniformRRect(image.Rectangle{Max: gtx.Constraints.Min}, rr).Push(gtx.Ops).Pop()
 				background := b.Background
 				switch {
-				case !gtx.Enabled():
+				case gtx.Queue == nil:
 					background = f32color.Disabled(b.Background)
-				case b.Button.Hovered() || gtx.Focused(b.Button):
+				case b.Button.Hovered() || b.Button.Focused():
 					background = f32color.Hovered(b.Background)
 				}
 				paint.Fill(gtx.Ops, background)
@@ -165,9 +165,9 @@ func (b IconButtonStyle) Layout(gtx layout.Context) layout.Dimensions {
 				defer clip.UniformRRect(image.Rectangle{Max: gtx.Constraints.Min}, rr).Push(gtx.Ops).Pop()
 				background := b.Background
 				switch {
-				case !gtx.Enabled():
+				case gtx.Queue == nil:
 					background = f32color.Disabled(b.Background)
-				case b.Button.Hovered() || gtx.Focused(b.Button):
+				case b.Button.Hovered() || b.Button.Focused():
 					background = f32color.Hovered(b.Background)
 				}
 				paint.Fill(gtx.Ops, background)
@@ -258,7 +258,7 @@ func drawInk(gtx layout.Context, c widget.Press) {
 
 	// Animate only ended presses, and presses that are fading in.
 	if !c.End.IsZero() || sizet <= 1.0 {
-		gtx.Execute(op.InvalidateCmd{})
+		op.InvalidateOp{}.Add(gtx.Ops)
 	}
 
 	if sizet > 1.0 {

widget/material/checkable.go

@@ -60,7 +60,7 @@ func (c *checkable) layout(gtx layout.Context, checked, hovered bool) layout.Dim
 					return layout.UniformInset(2).Layout(gtx, func(gtx layout.Context) layout.Dimensions {
 						size := gtx.Dp(c.Size)
 						col := c.IconColor
-						if !gtx.Enabled() {
+						if gtx.Queue == nil {
 							col = f32color.Disabled(col)
 						}
 						gtx.Constraints.Min = image.Point{X: size}

widget/material/checkbox.go

@@ -35,6 +35,6 @@ func CheckBox(th *Theme, checkBox *widget.Bool, label string) CheckBoxStyle {
 func (c CheckBoxStyle) Layout(gtx layout.Context) layout.Dimensions {
 	return c.CheckBox.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
 		semantic.CheckBox.Add(gtx.Ops)
-		return c.layout(gtx, c.CheckBox.Value, c.CheckBox.Hovered() || gtx.Focused(c.CheckBox))
+		return c.layout(gtx, c.CheckBox.Value, c.CheckBox.Hovered() || c.CheckBox.Focused())
 	})
 }

widget/material/doc.go

@@ -22,7 +22,7 @@
 //
 //	theme := material.NewTheme(...)
 //
-//	material.Button(theme, button, "Click me!").Layout(gtx)
+//	material.Button(theme, "Click me!").Layout(gtx, button)
 //
 // # Customization
 //
@@ -36,22 +36,22 @@
 // Theme-global parameters: For changing the look of all widgets drawn with a
 // particular theme, adjust the `Theme` fields:
 //
-//	theme.Palette.Fg = color.NRGBA{...}
+//	theme.Color.Primary = color.NRGBA{...}
 //
 // Widget-local parameters: For changing the look of a particular widget,
 // adjust the widget specific theme object:
 //
-//	btn := material.Button(theme, button, "Click me!")
+//	btn := material.Button(theme, "Click me!")
 //	btn.Font.Style = text.Italic
-//	btn.Layout(gtx)
+//	btn.Layout(gtx, button)
 //
 // Widget variants: A widget can have several distinct representations even
 // though the underlying state is the same. A widget.Clickable can be drawn as a
 // round icon button:
 //
-//	icon := widget.NewIcon(...)
+//	icon := material.NewIcon(...)
 //
-//	material.IconButton(theme, button, icon, "Click me!").Layout(gtx)
+//	material.IconButton(theme, icon).Layout(gtx, button)
 //
 // Specialized widgets: Theme both define a generic Label method
 // that takes a text size, and specialized methods for standard text

widget/material/editor.go

@@ -61,7 +61,7 @@ func (e EditorStyle) Layout(gtx layout.Context) layout.Dimensions {
 	paint.ColorOp{Color: e.HintColor}.Add(gtx.Ops)
 	hintColor := hintColorMacro.Stop()
 	selectionColorMacro := op.Record(gtx.Ops)
-	paint.ColorOp{Color: blendDisabledColor(!gtx.Enabled(), e.SelectionColor)}.Add(gtx.Ops)
+	paint.ColorOp{Color: blendDisabledColor(gtx.Queue == nil, e.SelectionColor)}.Add(gtx.Ops)
 	selectionColor := selectionColorMacro.Stop()
 
 	var maxlines int

widget/material/list.go

@@ -144,7 +144,7 @@ func (s ScrollbarStyle) Layout(gtx layout.Context, axis layout.Axis, viewportSta
 	gtx.Constraints.Min = convert(gtx.Constraints.Min)
 	gtx.Constraints.Max = gtx.Constraints.Min
 
-	s.Scrollbar.Update(gtx, axis, viewportStart, viewportEnd)
+	s.Scrollbar.Layout(gtx, axis, viewportStart, viewportEnd)
 
 	// Darken indicator if hovered.
 	if s.Scrollbar.IndicatorHovered() {

widget/material/list_test.go

@@ -3,7 +3,9 @@ package material_test
 import (
 	"image"
 	"testing"
+	"time"
 
+	"gioui.org/io/system"
 	"gioui.org/layout"
 	"gioui.org/op"
 	"gioui.org/unit"
@@ -12,17 +14,18 @@ import (
 )
 
 func TestListAnchorStrategies(t *testing.T) {
-	gtx := layout.Context{
+	var ops op.Ops
-		Ops: new(op.Ops),
+	gtx := layout.NewContext(&ops, system.FrameEvent{
 		Metric: unit.Metric{
 			PxPerDp: 1,
 			PxPerSp: 1,
 		},
-		Constraints: layout.Exact(image.Point{
+		Now: time.Now(),
+		Size: image.Point{
 			X: 500,
 			Y: 500,
-		}),
+		},
-	}
+	})
 	gtx.Constraints.Min = image.Point{}
 
 	var spaceConstraints layout.Constraints

widget/material/loader.go

@@ -47,7 +47,7 @@ func (l LoaderStyle) Layout(gtx layout.Context) layout.Dimensions {
 	}.Add(gtx.Ops)
 	defer op.Offset(image.Pt(-radius, -radius)).Push(gtx.Ops).Pop()
 	paint.PaintOp{}.Add(gtx.Ops)
-	gtx.Execute(op.InvalidateCmd{})
+	op.InvalidateOp{}.Add(gtx.Ops)
 	return layout.Dimensions{
 		Size: sz,
 	}

widget/material/progressbar.go

@@ -15,8 +15,6 @@ import (
 
 type ProgressBarStyle struct {
 	Color      color.NRGBA
-	Height     unit.Dp
-	Radius     unit.Dp
 	TrackColor color.NRGBA
 	Progress   float32
 }
@@ -24,8 +22,6 @@ type ProgressBarStyle struct {
 func ProgressBar(th *Theme, progress float32) ProgressBarStyle {
 	return ProgressBarStyle{
 		Progress:   progress,
-		Height:     unit.Dp(4),
-		Radius:     unit.Dp(2),
 		Color:      th.Palette.ContrastBg,
 		TrackColor: f32color.MulAlpha(th.Palette.Fg, 0x88),
 	}
@@ -33,8 +29,10 @@ func ProgressBar(th *Theme, progress float32) ProgressBarStyle {
 
 func (p ProgressBarStyle) Layout(gtx layout.Context) layout.Dimensions {
 	shader := func(width int, color color.NRGBA) layout.Dimensions {
-		d := image.Point{X: width, Y: gtx.Dp(p.Height)}
+		const maxHeight = unit.Dp(4)
-		rr := gtx.Dp(p.Radius)
+		rr := gtx.Dp(2)
+
+		d := image.Point{X: width, Y: gtx.Dp(maxHeight)}
 
 		defer clip.UniformRRect(image.Rectangle{Max: image.Pt(width, d.Y)}, rr).Push(gtx.Ops).Pop()
 		paint.ColorOp{Color: color}.Add(gtx.Ops)
@@ -51,7 +49,7 @@ func (p ProgressBarStyle) Layout(gtx layout.Context) layout.Dimensions {
 		layout.Stacked(func(gtx layout.Context) layout.Dimensions {
 			fillWidth := int(float32(progressBarWidth) * clamp1(p.Progress))
 			fillColor := p.Color
-			if !gtx.Enabled() {
+			if gtx.Queue == nil {
 				fillColor = f32color.Disabled(fillColor)
 			}
 			return shader(fillWidth, fillColor)

widget/material/slider.go

@@ -56,7 +56,7 @@ func (s SliderStyle) Layout(gtx layout.Context) layout.Dimensions {
 	trans.Pop()
 
 	color := s.Color
-	if !gtx.Enabled() {
+	if gtx.Queue == nil {
 		color = f32color.Disabled(color)
 	}
 

widget/material/switch.go

@@ -55,7 +55,7 @@ func (s SwitchStyle) Layout(gtx layout.Context) layout.Dimensions {
 	if s.Switch.Value {
 		col = s.Color.Enabled
 	}
-	if !gtx.Enabled() {
+	if gtx.Queue == nil {
 		col = f32color.Disabled(col)
 	}
 	trackColor := s.Color.Track
@@ -98,7 +98,7 @@ func (s SwitchStyle) Layout(gtx layout.Context) layout.Dimensions {
 		return clip.Ellipse(b).Op(gtx.Ops)
 	}
 	// Draw hover.
-	if s.Switch.Hovered() || gtx.Focused(s.Switch) {
+	if s.Switch.Hovered() || s.Switch.Focused() {
 		r := thumbRadius * 10 / 17
 		background := f32color.MulAlpha(s.Color.Enabled, 70)
 		paint.FillShape(gtx.Ops, background, circle(thumbRadius, thumbRadius, r))

widget/selectable.go

@@ -2,7 +2,6 @@ package widget
 
 import (
 	"image"
-	"io"
 	"math"
 	"strings"
 
@@ -71,14 +70,21 @@ type Selectable struct {
 	source          stringSource
 	// scratch is a buffer reused to efficiently read text out of the
 	// textView.
-	scratch   []byte
+	scratch      []byte
-	lastValue string
+	lastValue    string
-	text      textView
+	text         textView
-	focused   bool
+	focused      bool
-	dragging  bool
+	requestFocus bool
-	dragger   gesture.Drag
+	dragging     bool
+	dragger      gesture.Drag
+	scroller     gesture.Scroll
+	scrollOff    image.Point
 
 	clicker gesture.Click
+	// events is the list of events not yet processed.
+	events []EditorEvent
+	// prevEvents is the number of events from the previous frame.
+	prevEvents int
 }
 
 // initialize must be called at the beginning of any exported method that
@@ -92,6 +98,11 @@ func (l *Selectable) initialize() {
 	}
 }
 
+// Focus requests the input focus for the label.
+func (l *Selectable) Focus() {
+	l.requestFocus = true
+}
+
 // Focused returns whether the label is focused or not.
 func (l *Selectable) Focused() bool {
 	return l.focused
@@ -171,11 +182,10 @@ func (l *Selectable) Truncated() bool {
 	return l.text.Truncated()
 }
 
-// Update the state of the selectable in response to input events. It returns whether the
+// Update the state of the selectable in response to input events.
-// text selection changed during event processing.
+func (l *Selectable) Update(gtx layout.Context) {
-func (l *Selectable) Update(gtx layout.Context) bool {
 	l.initialize()
-	return l.handleEvents(gtx)
+	l.handleEvents(gtx)
 }
 
 // Layout clips to the dimensions of the selectable, updates the shaped text, configures input handling, and paints
@@ -193,7 +203,17 @@ func (l *Selectable) Layout(gtx layout.Context, lt *text.Shaper, font font.Font,
 	dims := l.text.Dimensions()
 	defer clip.Rect(image.Rectangle{Max: dims.Size}).Push(gtx.Ops).Pop()
 	pointer.CursorText.Add(gtx.Ops)
-	event.Op(gtx.Ops, l)
+	var keys key.Set
+	if l.focused {
+		const keyFilter = "(ShortAlt)-(Shift)-[←,→,↑,↓]|(Shift)-[⇞,⇟,⇱,⇲]|Short-[C,X,A]"
+		keys = keyFilter
+	}
+	key.InputOp{Tag: l, Keys: keys}.Add(gtx.Ops)
+	if l.requestFocus {
+		key.FocusOp{Tag: l}.Add(gtx.Ops)
+		key.SoftKeyboardOp{Show: true}.Add(gtx.Ops)
+	}
+	l.requestFocus = false
 
 	l.clicker.Add(gtx.Ops)
 	l.dragger.Add(gtx.Ops)
@@ -203,16 +223,18 @@ func (l *Selectable) Layout(gtx layout.Context, lt *text.Shaper, font font.Font,
 	return dims
 }
 
-func (l *Selectable) handleEvents(gtx layout.Context) (selectionChanged bool) {
+func (l *Selectable) handleEvents(gtx layout.Context) {
+	// Flush events from before the previous Layout.
+	n := copy(l.events, l.events[l.prevEvents:])
+	l.events = l.events[:n]
+	l.prevEvents = n
 	oldStart, oldLen := min(l.text.Selection()), l.text.SelectionLen()
-	defer func() {
-		if newStart, newLen := min(l.text.Selection()), l.text.SelectionLen(); oldStart != newStart || oldLen != newLen {
-			selectionChanged = true
-		}
-	}()
 	l.processPointer(gtx)
 	l.processKey(gtx)
-	return selectionChanged
+	// Queue a SelectEvent if the selection changed, including if it went away.
+	if newStart, newLen := min(l.text.Selection()), l.text.SelectionLen(); oldStart != newStart || oldLen != newLen {
+		l.events = append(l.events, SelectEvent{})
+	}
 }
 
 func (e *Selectable) processPointer(gtx layout.Context) {
@@ -227,7 +249,7 @@ func (e *Selectable) processPointer(gtx layout.Context) {
 					X: int(math.Round(float64(evt.Position.X))),
 					Y: int(math.Round(float64(evt.Position.Y))),
 				})
-				gtx.Execute(key.FocusCmd{Tag: e})
+				e.requestFocus = true
 				if evt.Modifiers == key.ModShift {
 					start, end := e.text.Selection()
 					// If they clicked closer to the end, then change the end to
@@ -276,44 +298,17 @@ func (e *Selectable) processPointer(gtx layout.Context) {
 
 func (e *Selectable) clickDragEvents(gtx layout.Context) []event.Event {
 	var combinedEvents []event.Event
-	for {
+	for _, evt := range e.clicker.Update(gtx) {
-		evt, ok := e.clicker.Update(gtx.Source)
-		if !ok {
-			break
-		}
 		combinedEvents = append(combinedEvents, evt)
 	}
-	for {
+	for _, evt := range e.dragger.Update(gtx.Metric, gtx, gesture.Both) {
-		evt, ok := e.dragger.Update(gtx.Metric, gtx.Source, gesture.Both)
-		if !ok {
-			break
-		}
 		combinedEvents = append(combinedEvents, evt)
 	}
 	return combinedEvents
 }
 
 func (e *Selectable) processKey(gtx layout.Context) {
-	for {
+	for _, ke := range gtx.Events(e) {
-		ke, ok := gtx.Event(
-			key.FocusFilter{Target: e},
-			key.Filter{Focus: e, Name: key.NameLeftArrow, Optional: key.ModShortcutAlt | key.ModShift},
-			key.Filter{Focus: e, Name: key.NameRightArrow, Optional: key.ModShortcutAlt | key.ModShift},
-			key.Filter{Focus: e, Name: key.NameUpArrow, Optional: key.ModShortcutAlt | key.ModShift},
-			key.Filter{Focus: e, Name: key.NameDownArrow, Optional: key.ModShortcutAlt | key.ModShift},
-
-			key.Filter{Focus: e, Name: key.NamePageUp, Optional: key.ModShift},
-			key.Filter{Focus: e, Name: key.NamePageDown, Optional: key.ModShift},
-			key.Filter{Focus: e, Name: key.NameEnd, Optional: key.ModShift},
-			key.Filter{Focus: e, Name: key.NameHome, Optional: key.ModShift},
-
-			key.Filter{Focus: e, Name: "C", Required: key.ModShortcut},
-			key.Filter{Focus: e, Name: "X", Required: key.ModShortcut},
-			key.Filter{Focus: e, Name: "A", Required: key.ModShortcut},
-		)
-		if !ok {
-			break
-		}
 		switch ke := ke.(type) {
 		case key.FocusEvent:
 			e.focused = ke.Focus
@@ -342,7 +337,7 @@ func (e *Selectable) command(gtx layout.Context, k key.Event) {
 		case "C", "X":
 			e.scratch = e.text.SelectedText(e.scratch)
 			if text := string(e.scratch); text != "" {
-				gtx.Execute(clipboard.WriteCmd{Type: "application/text", Data: io.NopCloser(strings.NewReader(text))})
+				clipboard.WriteOp{Text: text}.Add(gtx.Ops)
 			}
 		// Select all
 		case "A":
@@ -384,6 +379,14 @@ func (e *Selectable) command(gtx layout.Context, k key.Event) {
 	}
 }
 
+// Events returns available text events.
+func (l *Selectable) Events() []EditorEvent {
+	events := l.events
+	l.events = nil
+	l.prevEvents = 0
+	return events
+}
+
 // Regions returns visible regions covering the rune range [start,end).
 func (l *Selectable) Regions(start, end int, regions []Region) []Region {
 	l.initialize()

widget/selectable_test.go

@@ -7,7 +7,6 @@ import (
 
 	"gioui.org/font"
 	"gioui.org/font/gofont"
-	"gioui.org/io/input"
 	"gioui.org/io/key"
 	"gioui.org/layout"
 	"gioui.org/op"
@@ -34,11 +33,9 @@ func TestSelectableZeroValue(t *testing.T) {
 
 // Verify that an existing selection is dismissed when you press arrow keys.
 func TestSelectableMove(t *testing.T) {
-	r := new(input.Router)
 	gtx := layout.Context{
 		Ops:    new(op.Ops),
 		Locale: english,
-		Source: r.Source(),
 	}
 	cache := text.NewShaper(text.NoSystemFonts(), text.WithCollection(gofont.Collection()))
 	fnt := font.Font{}
@@ -47,20 +44,13 @@ func TestSelectableMove(t *testing.T) {
 	str := `0123456789`
 
 	// Layout once to populate e.lines and get focus.
+	gtx.Queue = newQueue(key.FocusEvent{Focus: true})
 	s := new(Selectable)
 
-	gtx.Execute(key.FocusCmd{Tag: s})
 	s.SetText(str)
-	// Set up selection so the Selectable filters for all 4 directional keys.
 	s.Layout(gtx, cache, font.Font{}, fontSize, op.CallOp{}, op.CallOp{})
-	r.Frame(gtx.Ops)
-	s.SetCaret(3, 6)
-	s.Layout(gtx, cache, font.Font{}, fontSize, op.CallOp{}, op.CallOp{})
-	r.Frame(gtx.Ops)
-	s.Layout(gtx, cache, font.Font{}, fontSize, op.CallOp{}, op.CallOp{})
-	r.Frame(gtx.Ops)
 
-	for _, keyName := range []key.Name{key.NameLeftArrow, key.NameRightArrow, key.NameUpArrow, key.NameDownArrow} {
+	testKey := func(keyName string) {
 		// Select 345
 		s.SetCaret(3, 6)
 		if start, end := s.Selection(); start != 3 || end != 6 {
@@ -71,15 +61,19 @@ func TestSelectableMove(t *testing.T) {
 		}
 
 		// Press the key
-		r.Queue(key.Event{State: key.Press, Name: keyName})
+		gtx.Queue = newQueue(key.Event{State: key.Press, Name: keyName})
 		s.SetText(str)
 		s.Layout(gtx, cache, fnt, fontSize, op.CallOp{}, op.CallOp{})
-		r.Frame(gtx.Ops)
 
 		if expected, got := "", s.SelectedText(); expected != got {
 			t.Errorf("KeyName %s, expected %q, got %q", keyName, expected, got)
 		}
 	}
+
+	testKey(key.NameLeftArrow)
+	testKey(key.NameRightArrow)
+	testKey(key.NameUpArrow)
+	testKey(key.NameDownArrow)
 }
 
 func TestSelectableConfigurations(t *testing.T) {

widget/widget_test.go

@@ -7,9 +7,10 @@ import (
 	"testing"
 
 	"gioui.org/f32"
-	"gioui.org/io/input"
 	"gioui.org/io/pointer"
+	"gioui.org/io/router"
 	"gioui.org/io/semantic"
+	"gioui.org/io/system"
 	"gioui.org/layout"
 	"gioui.org/op"
 	"gioui.org/widget"
@@ -17,13 +18,11 @@ import (
 
 func TestBool(t *testing.T) {
 	var (
-		r input.Router
+		ops op.Ops
-		b widget.Bool
+		r   router.Router
+		b   widget.Bool
 	)
-	gtx := layout.Context{
+	gtx := layout.NewContext(&ops, system.FrameEvent{Queue: &r})
-		Ops:    new(op.Ops),
-		Source: r.Source(),
-	}
 	layout := func() {
 		b.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
 			semantic.CheckBox.Add(gtx.Ops)
@@ -45,7 +44,7 @@ func TestBool(t *testing.T) {
 			Position: f32.Pt(50, 50),
 		},
 	)
-	gtx.Reset()
+	ops.Reset()
 	layout()
 	r.Frame(gtx.Ops)
 	tree := r.AppendSemantics(nil)