ui,ui/app: convert Config to an interface

To keep the interface slim, remove the helper methods and shorten
the essential method, Pixels, to Px.

Add and use unexported Config implementation in the app package.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

ui/app/app.go

@@ -4,8 +4,10 @@ package app
 
 import (
 	"image"
+	"math"
 	"os"
 	"strings"
+	"time"
 
 	"gioui.org/ui"
 )
@@ -15,7 +17,7 @@ type Event interface {
 }
 
 type DrawEvent struct {
-	Config ui.Config
+	Config Config
 	Size   image.Point
 	// Insets is the window space taken up by
 	// system decoration such as translucent
@@ -131,3 +133,34 @@ func init() {
 func DataDir() (string, error) {
 	return dataDir()
 }
+
+// Config implements the ui.Config interface.
+type Config struct {
+	// Device pixels per dp.
+	pxPerDp float32
+	// Device pixels per sp.
+	pxPerSp float32
+	now     time.Time
+}
+
+func (c *Config) Now() time.Time {
+	return c.now
+}
+
+func (c *Config) Px(v ui.Value) int {
+	var r float32
+	switch v.U {
+	case ui.UnitPx:
+		r = v.V
+	case ui.UnitDp:
+		r = c.pxPerDp * v.V
+	case ui.UnitSp:
+		r = c.pxPerSp * v.V
+	default:
+		panic("unknown unit")
+	}
+	if math.IsInf(float64(r), +1) {
+		return ui.Inf
+	}
+	return int(math.Round(float64(r)))
+}

ui/app/os_android.go

@@ -24,7 +24,6 @@ import (
 	"time"
 	"unsafe"
 
-	"gioui.org/ui"
 	"gioui.org/ui/f32"
 	"gioui.org/ui/key"
 	"gioui.org/ui/pointer"
@@ -289,10 +288,10 @@ func (w *window) draw(sync bool) {
 			Y: int(height),
 		},
 		Insets: w.insets,
-		Config: ui.Config{
+		Config: Config{
-			PxPerDp: ppdp,
+			pxPerDp: ppdp,
-			PxPerSp: w.fontScale * ppdp,
+			pxPerSp: w.fontScale * ppdp,
-			Now:     time.Now(),
+			now:     time.Now(),
 		},
 		sync: sync,
 	})

ui/app/os_ios.go

@@ -22,7 +22,6 @@ import (
 	"sync/atomic"
 	"time"
 
-	"gioui.org/ui"
 	"gioui.org/ui/f32"
 	"gioui.org/ui/key"
 	"gioui.org/ui/pointer"
@@ -87,10 +86,10 @@ func onDraw(view C.CFTypeRef, dpi, sdpi, width, height C.CGFloat, sync C.int, to
 			Min: image.Point{X: int(left + .5), Y: int(top + .5)},
 			Max: image.Point{X: int(right + .5), Y: int(bottom + .5)},
 		},
-		Config: ui.Config{
+		Config: Config{
-			PxPerDp: float32(dpi) * inchPrDp,
+			pxPerDp: float32(dpi) * inchPrDp,
-			PxPerSp: float32(sdpi) * inchPrDp,
+			pxPerSp: float32(sdpi) * inchPrDp,
-			Now:     time.Now(),
+			now:     time.Now(),
 		},
 		sync: isSync,
 	})

ui/app/os_js.go

@@ -7,7 +7,6 @@ import (
 	"syscall/js"
 	"time"
 
-	"gioui.org/ui"
 	"gioui.org/ui/f32"
 	"gioui.org/ui/key"
 	"gioui.org/ui/pointer"
@@ -329,13 +328,13 @@ func (w *window) setTextInput(s key.TextInputState) {
 
 func (w *window) draw(sync bool) {
 	width, height, scale, cfg := w.config()
-	if cfg == (ui.Config{}) {
+	if cfg == (Config{}) {
 		return
 	}
 	w.mu.Lock()
 	w.scale = float32(scale)
 	w.mu.Unlock()
-	cfg.Now = time.Now()
+	cfg.now = time.Now()
 	w.w.event(DrawEvent{
 		Size: image.Point{
 			X: width,
@@ -346,7 +345,7 @@ func (w *window) draw(sync bool) {
 	})
 }
 
-func (w *window) config() (int, int, float32, ui.Config) {
+func (w *window) config() (int, int, float32, Config) {
 	rect := w.cnv.Call("getBoundingClientRect")
 	width, height := rect.Get("width").Float(), rect.Get("height").Float()
 	scale := w.window.Get("devicePixelRatio").Float()
@@ -359,9 +358,9 @@ func (w *window) config() (int, int, float32, ui.Config) {
 		w.cnv.Set("height", ih)
 	}
 	const ppdp = 96 * inchPrDp * monitorScale
-	return iw, ih, float32(scale), ui.Config{
+	return iw, ih, float32(scale), Config{
-		PxPerDp: ppdp * float32(scale),
+		pxPerDp: ppdp * float32(scale),
-		PxPerSp: ppdp * float32(scale),
+		pxPerSp: ppdp * float32(scale),
 	}
 }
 

ui/app/os_macos.go

@@ -19,7 +19,6 @@ import (
 	"time"
 	"unsafe"
 
-	"gioui.org/ui"
 	"gioui.org/ui/f32"
 	"gioui.org/ui/key"
 	"gioui.org/ui/pointer"
@@ -142,7 +141,7 @@ func (w *window) draw(sync bool) {
 		return
 	}
 	cfg := getConfig()
-	cfg.Now = time.Now()
+	cfg.now = time.Now()
 	w.setStage(StageRunning)
 	w.w.event(DrawEvent{
 		Size: image.Point{
@@ -154,15 +153,15 @@ func (w *window) draw(sync bool) {
 	})
 }
 
-func getConfig() ui.Config {
+func getConfig() Config {
 	ppdp := float32(C.gio_getPixelsPerDP())
 	ppdp *= monitorScale
 	if ppdp < minDensity {
 		ppdp = minDensity
 	}
-	return ui.Config{
+	return Config{
-		PxPerDp: ppdp,
+		pxPerDp: ppdp,
-		PxPerSp: ppdp,
+		pxPerSp: ppdp,
 	}
 }
 
@@ -216,8 +215,8 @@ func Main() {
 	}
 	cfg := getConfig()
 	opts := singleWindow.opts
-	w := cfg.Pixels(opts.Width)
+	w := cfg.Px(opts.Width)
-	h := cfg.Pixels(opts.Height)
+	h := cfg.Px(opts.Height)
 	title := C.CString(opts.Title)
 	defer C.free(unsafe.Pointer(title))
 	C.gio_main(view, title, C.CGFloat(w), C.CGFloat(h))

ui/app/os_wayland.go

@@ -19,7 +19,6 @@ import (
 	"unicode/utf8"
 	"unsafe"
 
-	"gioui.org/ui"
 	"gioui.org/ui/f32"
 	"gioui.org/ui/key"
 	"gioui.org/ui/pointer"
@@ -237,8 +236,8 @@ func createNativeWindow(opts *WindowOptions) (*window, error) {
 	C.free(unsafe.Pointer(title))
 
 	_, _, cfg := w.config()
-	w.width = cfg.Pixels(opts.Width)
+	w.width = cfg.Px(opts.Width)
-	w.height = cfg.Pixels(opts.Height)
+	w.height = cfg.Px(opts.Height)
 	if conn.decor != nil {
 		// Request server side decorations.
 		w.decor = C.zxdg_decoration_manager_v1_get_toplevel_decoration(conn.decor, w.topLvl)
@@ -1020,11 +1019,11 @@ func (w *window) updateOutputs() {
 	}
 }
 
-func (w *window) config() (int, int, ui.Config) {
+func (w *window) config() (int, int, Config) {
 	width, height := w.width*w.scale, w.height*w.scale
-	return width, height, ui.Config{
+	return width, height, Config{
-		PxPerDp: w.ppdp * float32(w.scale),
+		pxPerDp: w.ppdp * float32(w.scale),
-		PxPerSp: w.ppsp * float32(w.scale),
+		pxPerSp: w.ppsp * float32(w.scale),
 	}
 }
 
@@ -1036,7 +1035,7 @@ func (w *window) draw(sync bool) {
 		return
 	}
 	width, height, cfg := w.config()
-	if cfg == (ui.Config{}) {
+	if cfg == (Config{}) {
 		return
 	}
 	if animating && w.lastFrameCallback == nil {
@@ -1044,7 +1043,7 @@ func (w *window) draw(sync bool) {
 		// Use the surface as listener data for gio_onFrameDone.
 		C.gio_wl_callback_add_listener(w.lastFrameCallback, unsafe.Pointer(w.surf))
 	}
-	cfg.Now = time.Now()
+	cfg.now = time.Now()
 	w.w.event(DrawEvent{
 		Size: image.Point{
 			X: width,

ui/app/os_windows.go

@@ -13,7 +13,6 @@ import (
 
 	syscall "golang.org/x/sys/windows"
 
-	"gioui.org/ui"
 	"gioui.org/ui/f32"
 	"gioui.org/ui/key"
 	"gioui.org/ui/pointer"
@@ -220,8 +219,8 @@ func createNativeWindow(opts *WindowOptions) (*window, error) {
 	}
 	defer unregisterClass(cls, hInst)
 	wr := rect{
-		right:  int32(cfg.Pixels(opts.Width)),
+		right:  int32(cfg.Px(opts.Width)),
-		bottom: int32(cfg.Pixels(opts.Height)),
+		bottom: int32(cfg.Px(opts.Height)),
 	}
 	dwStyle := uint32(_WS_OVERLAPPEDWINDOW)
 	dwExStyle := uint32(_WS_EX_APPWINDOW | _WS_EX_WINDOWEDGE)
@@ -419,7 +418,7 @@ func (w *window) draw(sync bool) {
 	w.width = int(r.right - r.left)
 	w.height = int(r.bottom - r.top)
 	cfg := configForDC(w.hdc)
-	cfg.Now = time.Now()
+	cfg.now = time.Now()
 	w.w.event(DrawEvent{
 		Size: image.Point{
 			X: w.width,
@@ -487,16 +486,16 @@ func convertKeyCode(code uintptr) (rune, bool) {
 	return r, true
 }
 
-func configForDC(hdc syscall.Handle) ui.Config {
+func configForDC(hdc syscall.Handle) Config {
 	dpi := getDeviceCaps(hdc, _LOGPIXELSX)
 	ppdp := float32(dpi) * inchPrDp * monitorScale
 	// Force a minimum density to keep text legible and to handle bogus output geometry.
 	if ppdp < minDensity {
 		ppdp = minDensity
 	}
-	return ui.Config{
+	return Config{
-		PxPerDp: ppdp,
+		pxPerDp: ppdp,
-		PxPerSp: ppdp,
+		pxPerSp: ppdp,
 	}
 }
 

ui/gesture/gestures.go

@@ -133,7 +133,7 @@ func (s *Scroll) Dragging() bool {
 	return s.dragging
 }
 
-func (s *Scroll) Scroll(cfg *ui.Config, q input.Events, axis Axis) int {
+func (s *Scroll) Scroll(cfg ui.Config, q input.Events, axis Axis) int {
 	if s.axis != axis {
 		s.axis = axis
 		return 0
@@ -165,15 +165,15 @@ func (s *Scroll) Scroll(cfg *ui.Config, q input.Events, axis Axis) int {
 				break
 			}
 			fling := s.estimator.Estimate()
-			if slop, d := float32(cfg.Pixels(touchSlop)), fling.Distance; d >= slop || -slop >= d {
+			if slop, d := float32(cfg.Px(touchSlop)), fling.Distance; d >= slop || -slop >= d {
-				if min, v := float32(cfg.Pixels(minFlingVelocity)), fling.Velocity; v >= min || -min >= v {
+				if min, v := float32(cfg.Px(minFlingVelocity)), fling.Velocity; v >= min || -min >= v {
-					max := float32(cfg.Pixels(maxFlingVelocity))
+					max := float32(cfg.Px(maxFlingVelocity))
 					if v > max {
 						v = max
 					} else if v < -max {
 						v = -max
 					}
-					s.flinger.Init(cfg.Now, v)
+					s.flinger.Init(cfg.Now(), v)
 				}
 			}
 			fallthrough
@@ -200,7 +200,7 @@ func (s *Scroll) Scroll(cfg *ui.Config, q input.Events, axis Axis) int {
 			v := int(math.Round(float64(val)))
 			dist := s.last - v
 			if e.Priority < pointer.Grabbed {
-				slop := cfg.Pixels(touchSlop)
+				slop := cfg.Px(touchSlop)
 				if dist := dist; dist >= slop || -slop >= dist {
 					s.grab = true
 				}
@@ -210,7 +210,7 @@ func (s *Scroll) Scroll(cfg *ui.Config, q input.Events, axis Axis) int {
 			}
 		}
 	}
-	total += s.flinger.Tick(cfg.Now)
+	total += s.flinger.Tick(cfg.Now())
 	return total
 }
 

ui/layout/layout.go

@@ -96,14 +96,14 @@ type Insets struct {
 	cs                       Constraints
 }
 
-func (in *Insets) Begin(c *ui.Config, ops *ui.Ops, cs Constraints) Constraints {
+func (in *Insets) Begin(c ui.Config, ops *ui.Ops, cs Constraints) Constraints {
 	if in.begun {
 		panic("must End before Begin")
 	}
-	in.top = c.Pixels(in.Top)
+	in.top = c.Px(in.Top)
-	in.right = c.Pixels(in.Right)
+	in.right = c.Px(in.Right)
-	in.bottom = c.Pixels(in.Bottom)
+	in.bottom = c.Px(in.Bottom)
-	in.left = c.Pixels(in.Left)
+	in.left = c.Px(in.Left)
 	in.begun = true
 	in.ops = ops
 	in.cs = cs

ui/layout/list.go

@@ -18,7 +18,7 @@ type scrollChild struct {
 }
 
 type List struct {
-	Config             *ui.Config
+	Config             ui.Config
 	Inputs             input.Events
 	Axis               Axis
 	Invert             bool

ui/measure/measure.go

@@ -17,7 +17,7 @@ import (
 )
 
 type Faces struct {
-	Config      *ui.Config
+	Config      ui.Config
 	faceCache   map[faceKey]*textFace
 	layoutCache map[layoutKey]cachedLayout
 	pathCache   map[pathKey]cachedPath
@@ -102,7 +102,7 @@ func (f *Faces) init() {
 }
 
 func (f *textFace) Layout(str string, opts text.LayoutOptions) *text.Layout {
-	ppem := fixed.Int26_6(f.faces.Config.Pixels(f.size) * 64)
+	ppem := fixed.Int26_6(f.faces.Config.Px(f.size) * 64)
 	lk := layoutKey{
 		f:    f.font.Font,
 		ppem: ppem,
@@ -120,7 +120,7 @@ func (f *textFace) Layout(str string, opts text.LayoutOptions) *text.Layout {
 }
 
 func (f *textFace) Path(str text.String) ui.BlockOp {
-	ppem := fixed.Int26_6(f.faces.Config.Pixels(f.size) * 64)
+	ppem := fixed.Int26_6(f.faces.Config.Px(f.size) * 64)
 	pk := pathKey{
 		f:    f.font.Font,
 		ppem: ppem,

ui/text/editor.go

@@ -21,7 +21,7 @@ import (
 )
 
 type Editor struct {
-	Config     *ui.Config
+	Config     ui.Config
 	Inputs     input.Events
 	Face       Face
 	Alignment  Alignment
@@ -32,7 +32,7 @@ type Editor struct {
 	Hint         string
 	HintMaterial ui.BlockOp
 
-	oldCfg            ui.Config
+	oldScale          int
 	blinkStart        time.Time
 	focused           bool
 	rr                editBuffer
@@ -73,9 +73,10 @@ func (s ChangeEvent) isEditorEvent() {}
 func (s SubmitEvent) isEditorEvent() {}
 
 func (e *Editor) Next() (EditorEvent, bool) {
-	if cfg := *e.Config; cfg != e.oldCfg {
+	// Crude configuration change detection.
+	if scale := e.Config.Px(ui.Sp(100)); scale != e.oldScale {
 		e.invalidate()
-		e.oldCfg = cfg
+		e.oldScale = scale
 	}
 	sbounds := e.scrollBounds()
 	var smin, smax int
@@ -104,7 +105,7 @@ func (e *Editor) Next() (EditorEvent, bool) {
 		switch {
 		case evt.Type == gesture.TypePress && evt.Source == pointer.Mouse,
 			evt.Type == gesture.TypeClick && evt.Source == pointer.Touch:
-			e.blinkStart = e.Config.Now
+			e.blinkStart = e.Config.Now()
 			e.moveCoord(image.Point{
 				X: int(math.Round(float64(evt.Position.X))),
 				Y: int(math.Round(float64(evt.Position.Y))),
@@ -123,7 +124,7 @@ func (e *Editor) Next() (EditorEvent, bool) {
 		if !ok {
 			break
 		}
-		e.blinkStart = e.Config.Now
+		e.blinkStart = e.Config.Now()
 		switch ke := ke.(type) {
 		case key.FocusEvent:
 			e.focused = ke.Focus
@@ -153,7 +154,7 @@ func (e *Editor) Next() (EditorEvent, bool) {
 }
 
 func (e *Editor) caretWidth() fixed.Int26_6 {
-	oneDp := e.Config.Dp(1)
+	oneDp := e.Config.Px(ui.Dp(1))
 	return fixed.Int26_6(oneDp * 64)
 }
 
@@ -167,7 +168,7 @@ func (e *Editor) Layout(ops *ui.Ops, cs layout.Constraints) layout.Dimens {
 			break
 		}
 	}
-	twoDp := e.Config.Dp(2)
+	twoDp := e.Config.Px(ui.Dp(2))
 	e.padLeft, e.padRight = twoDp, twoDp
 	maxWidth := cs.Width.Max
 	if e.SingleLine {
@@ -225,7 +226,7 @@ func (e *Editor) Layout(ops *ui.Ops, cs layout.Constraints) layout.Dimens {
 		ui.PopOp{}.Add(ops)
 	}
 	if e.focused {
-		now := e.Config.Now
+		now := e.Config.Now()
 		dt := now.Sub(e.blinkStart)
 		blinking := dt < maxBlinkDuration
 		const timePerBlink = time.Second / blinksPerSecond

ui/ui.go

@@ -11,41 +11,13 @@ import (
 	"gioui.org/ui/internal/ops"
 )
 
-// Config contains the essential configuration for
+// Config represents the essential configuration for
 // updating and drawing a user interface.
-type Config struct {
+type Config interface {
-	// Device pixels per dp.
+	// Now returns the current animation time.
-	PxPerDp float32
+	Now() time.Time
-	// Device pixels per sp.
+	// Px converts a Value to pixels.
-	PxPerSp float32
+	Px(v Value) int
-	// The current time for animation.
-	Now time.Time
-}
-
-// Dp converts a value in dp units to pixels.
-func (c *Config) Dp(dp float32) int {
-	return c.Pixels(Dp(dp))
-}
-
-// Sp converts a value in sp units to pixels.
-func (c *Config) Sp(sp float32) int {
-	return c.Pixels(Sp(sp))
-}
-
-// Pixels converts a value to pixels.
-func (c *Config) Pixels(v Value) int {
-	var r float32
-	switch v.U {
-	case UnitPx:
-		r = v.V
-	case UnitDp:
-		r = c.PxPerDp * v.V
-	case UnitSp:
-		r = c.PxPerSp * v.V
-	default:
-		panic("unknown unit")
-	}
-	return int(math.Round(float64(r)))
 }
 
 // LayerOp represents a semantic layer of UI.

ui/widget/image.go

@@ -23,13 +23,13 @@ type Image struct {
 	Scale float32
 }
 
-func (im Image) Layout(c *ui.Config, ops *ui.Ops, cs layout.Constraints) layout.Dimens {
+func (im Image) Layout(c ui.Config, ops *ui.Ops, cs layout.Constraints) layout.Dimens {
 	size := im.Src.Bounds()
 	wf, hf := float32(size.Dx()), float32(size.Dy())
 	var w, h int
 	if im.Scale == 0 {
 		const dpPrPx = 160 / 72
-		w, h = c.Dp(wf*dpPrPx), c.Dp(hf*dpPrPx)
+		w, h = c.Px(ui.Dp(wf*dpPrPx)), c.Px(ui.Dp(hf*dpPrPx))
 	} else {
 		w, h = int(wf*im.Scale+.5), int(hf*im.Scale+.5)
 	}