io/input: support direct pointer leave events

Allow platform backends to send pointer.Leave directly.
The router delivers it to entered handlers so hover state is cleared normally.

app/os_windows.go

@@ -369,8 +369,7 @@ func windowProc(hwnd syscall.Handle, msg uint32, wParam, lParam uintptr) uintptr
 		w.update()
 	case windows.WM_WINDOWPOSCHANGED:
 		w.update()
-	case windows.WM_SIZE:
-		w.update()
+		return 0
 	case windows.WM_GETMINMAXINFO:
 		mm := (*windows.MinMaxInfo)(unsafe.Pointer(lParam))
 
@@ -495,34 +494,32 @@ func getModifiers() key.Modifiers {
 // hitTest returns the non-client area hit by the point, needed to
 // process WM_NCHITTEST.
 func (w *window) hitTest(x, y int) uintptr {
-	if w.config.Mode != Windowed {
-		// Only windowed mode should allow resizing.
-		return windows.HTCLIENT
-	}
-	// Check for resize handle before system actions; otherwise it can be impossible to
-	// resize a custom-decorations window when the system move area is flush with the
-	// edge of the window.
-	top := y <= w.borderSize.Y
-	bottom := y >= w.config.Size.Y-w.borderSize.Y
-	left := x <= w.borderSize.X
-	right := x >= w.config.Size.X-w.borderSize.X
-	switch {
-	case top && left:
-		return windows.HTTOPLEFT
-	case top && right:
-		return windows.HTTOPRIGHT
-	case bottom && left:
-		return windows.HTBOTTOMLEFT
-	case bottom && right:
-		return windows.HTBOTTOMRIGHT
-	case top:
-		return windows.HTTOP
-	case bottom:
-		return windows.HTBOTTOM
-	case left:
-		return windows.HTLEFT
-	case right:
-		return windows.HTRIGHT
+	if w.config.Mode == Windowed {
+		// Check for resize handle before system actions; otherwise it can be impossible to
+		// resize a custom-decorations window when the system move area is flush with the
+		// edge of the window.
+		top := y <= w.borderSize.Y
+		bottom := y >= w.config.Size.Y-w.borderSize.Y
+		left := x <= w.borderSize.X
+		right := x >= w.config.Size.X-w.borderSize.X
+		switch {
+		case top && left:
+			return windows.HTTOPLEFT
+		case top && right:
+			return windows.HTTOPRIGHT
+		case bottom && left:
+			return windows.HTBOTTOMLEFT
+		case bottom && right:
+			return windows.HTBOTTOMRIGHT
+		case top:
+			return windows.HTTOP
+		case bottom:
+			return windows.HTBOTTOM
+		case left:
+			return windows.HTLEFT
+		case right:
+			return windows.HTRIGHT
+		}
 	}
 	p := f32.Pt(float32(x), float32(y))
 	if a, ok := w.w.ActionAt(p); ok && a == system.ActionMove {

internal/egl/egl_windows.go

@@ -41,14 +41,10 @@ var (
 	_eglWaitClient          *syscall.Proc
 )
 
-var loadOnce sync.Once
+var loadOnce = sync.OnceValue(loadDLLs)
 
 func loadEGL() error {
-	var err error
-	loadOnce.Do(func() {
-		err = loadDLLs()
-	})
-	return err
+	return loadOnce()
 }
 
 func loadDLLs() error {

io/input/pointer.go

@@ -760,6 +760,8 @@ func (q *pointerQueue) Push(handlers map[event.Tag]*handler, state pointerState,
 		if p.pressed {
 			p, evts = q.deliverDragEvent(handlers, p, evts)
 		}
+	case pointer.Leave:
+		p, evts, state.cursor, _ = q.deliverEnterLeaveEvents(handlers, state.cursor, p, evts, e)
 	case pointer.Release:
 		evts = q.deliverEvent(handlers, p, evts, e)
 		p.pressed = false
@@ -823,7 +825,7 @@ func (q *pointerQueue) deliverEvent(handlers map[event.Tag]*handler, p pointerIn
 func (q *pointerQueue) deliverEnterLeaveEvents(handlers map[event.Tag]*handler, cursor pointer.Cursor, p pointerInfo, evts []taggedEvent, e pointer.Event) (pointerInfo, []taggedEvent, pointer.Cursor, bool) {
 	changed := false
 	var hits []event.Tag
-	if e.Source != pointer.Mouse && !p.pressed && e.Kind != pointer.Press {
+	if e.Kind == pointer.Leave || e.Source != pointer.Mouse && !p.pressed && e.Kind != pointer.Press {
 		// Consider non-mouse pointers leaving when they're released.
 	} else {
 		var transSrc *pointerFilter

io/input/pointer_test.go

@@ -255,6 +255,45 @@ func TestPointerMove(t *testing.T) {
 	assertEventPointerTypeSequence(t, events(&r, -1, filter(handler2)), pointer.Enter, pointer.Move, pointer.Leave, pointer.Cancel)
 }
 
+func TestPointerLeave(t *testing.T) {
+	handler := new(int)
+	var ops op.Ops
+
+	filter := pointer.Filter{
+		Target: handler,
+		Kinds:  pointer.Move | pointer.Enter | pointer.Leave | pointer.Cancel,
+	}
+	defer clip.Rect(image.Rect(0, 0, 100, 100)).Push(&ops).Pop()
+	event.Op(&ops, handler)
+
+	var r Router
+	events(&r, -1, filter)
+	r.Frame(&ops)
+	r.Queue(
+		pointer.Event{
+			Kind:      pointer.Move,
+			Source:    pointer.Mouse,
+			PointerID: 1,
+			Position:  f32.Pt(50, 50),
+		},
+		pointer.Event{
+			Kind:      pointer.Leave,
+			Source:    pointer.Mouse,
+			PointerID: 1,
+			Position:  f32.Pt(50, 50),
+		},
+	)
+	assertEventPointerTypeSequence(t, events(&r, -1, filter), pointer.Enter, pointer.Move, pointer.Leave)
+
+	r.Queue(pointer.Event{
+		Kind:      pointer.Move,
+		Source:    pointer.Mouse,
+		PointerID: 1,
+		Position:  f32.Pt(50, 50),
+	})
+	assertEventPointerTypeSequence(t, events(&r, -1, filter), pointer.Enter, pointer.Move)
+}
+
 func TestPointerTypes(t *testing.T) {
 	handler := new(int)
 	var ops op.Ops

widget/material/decorations.go

@@ -5,7 +5,6 @@ import (
 	"image/color"
 
 	"gioui.org/f32"
-	"gioui.org/io/semantic"
 	"gioui.org/io/system"
 	"gioui.org/layout"
 	"gioui.org/op"
@@ -86,21 +85,10 @@ func (d DecorationsStyle) layoutDecorations(gtx layout.Context) layout.Dimension
 					continue
 				}
 				cl := d.Decorations.Clickable(a)
-				dims := cl.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
-					semantic.Button.Add(gtx.Ops)
-					return layout.Background{}.Layout(gtx,
-						func(gtx layout.Context) layout.Dimensions {
-							defer clip.Rect{Max: gtx.Constraints.Min}.Push(gtx.Ops).Pop()
-							for _, c := range cl.History() {
-								drawInk(gtx, c)
-							}
-							return layout.Dimensions{Size: gtx.Constraints.Min}
-						},
-						func(gtx layout.Context) layout.Dimensions {
-							paint.ColorOp{Color: d.Foreground}.Add(gtx.Ops)
-							return inset.Layout(gtx, w)
-						},
-					)
+				dims := Clickable(gtx, cl, func(gtx layout.Context) layout.Dimensions {
+					system.ActionInputOp(a).Add(gtx.Ops)
+					paint.ColorOp{Color: d.Foreground}.Add(gtx.Ops)
+					return inset.Layout(gtx, w)
 				})
 				size.X += dims.Size.X
 				if size.Y < dims.Size.Y {