app: update TopMost comment

TopMost is also supported on Windows.

Signed-off-by: qiannian <qianniancn@gmail.com>

app/internal/windows/windows.go

@@ -207,7 +207,9 @@ const (
 	CFS_POINT        = 0x0002
 	CFS_CANDIDATEPOS = 0x0040
 
-	HWND_TOPMOST = ^(uint32(1) - 1) // -1
+	HWND_TOP       = syscall.Handle(0)
+	HWND_TOPMOST   = ^(syscall.Handle(1) - 1) // -1
+	HWND_NOTOPMOST = ^(syscall.Handle(2) - 1) // -2
 
 	HTCAPTION     = 2
 	HTCLIENT      = 1
@@ -782,7 +784,7 @@ func SetWindowPlacement(hwnd syscall.Handle, wp *WindowPlacement) {
 	_SetWindowPlacement.Call(uintptr(hwnd), uintptr(unsafe.Pointer(wp)))
 }
 
-func SetWindowPos(hwnd syscall.Handle, hwndInsertAfter uint32, x, y, dx, dy int32, style uintptr) {
+func SetWindowPos(hwnd, hwndInsertAfter syscall.Handle, x, y, dx, dy int32, style uintptr) {
 	_SetWindowPos.Call(uintptr(hwnd), uintptr(hwndInsertAfter),
 		uintptr(x), uintptr(y),
 		uintptr(dx), uintptr(dy),

app/os_windows.go

@@ -412,6 +412,7 @@ func windowProc(hwnd syscall.Handle, msg uint32, wParam, lParam uintptr) uintptr
 		icaret := image.Pt(int(caret.X+.5), int(caret.Y+.5))
 		windows.ImmSetCompositionWindow(imc, icaret.X, icaret.Y)
 		windows.ImmSetCandidateWindow(imc, icaret.X, icaret.Y)
+		return windows.TRUE
 	case windows.WM_IME_COMPOSITION:
 		imc := windows.ImmGetContext(w.hwnd)
 		if imc == 0 {
@@ -698,7 +699,13 @@ func (w *window) ReadClipboard() {
 	w.readClipboard()
 }
 
-func (w *window) readClipboard() error {
+func (w *window) readClipboard() (cerr error) {
+	defer func() {
+		if cerr != nil {
+			w.processDataEvent("")
+		}
+	}()
+
 	if err := windows.OpenClipboard(w.hwnd); err != nil {
 		return err
 	}
@@ -713,13 +720,17 @@ func (w *window) readClipboard() error {
 	}
 	defer windows.GlobalUnlock(mem)
 	content := gowindows.UTF16PtrToString((*uint16)(unsafe.Pointer(ptr)))
+	w.processDataEvent(content)
+	return nil
+}
+
+func (w *window) processDataEvent(content string) {
 	w.ProcessEvent(transfer.DataEvent{
 		Type: "application/text",
 		Open: func() io.ReadCloser {
 			return io.NopCloser(strings.NewReader(content))
 		},
 	})
-	return nil
 }
 
 func (w *window) Configure(options []Option) {
@@ -736,7 +747,16 @@ func (w *window) Configure(options []Option) {
 	style := windows.GetWindowLong(w.hwnd, windows.GWL_STYLE)
 	var showMode int32
 	var x, y, width, height int32
-	swpStyle := uintptr(windows.SWP_NOZORDER | windows.SWP_FRAMECHANGED)
+	swpStyle := uintptr(windows.SWP_FRAMECHANGED)
+	if cnf.TopMost == w.config.TopMost {
+		// Don't change the z-order if TopMost didn't change.
+		swpStyle |= windows.SWP_NOZORDER
+	}
+	hwndAfter := windows.HWND_NOTOPMOST
+	if cnf.TopMost {
+		hwndAfter = windows.HWND_TOPMOST
+	}
+	w.config.TopMost = cnf.TopMost
 	winStyle := uintptr(windows.WS_OVERLAPPEDWINDOW)
 	style &^= winStyle
 	switch cnf.Mode {
@@ -788,7 +808,7 @@ func (w *window) Configure(options []Option) {
 
 	// Note: these invocation all trigger the windows callback method which may process a pending system.ActionCenter
 	// action, so SetWindowPos should come first so as to not "overwrite" system.ActionCenter.
-	windows.SetWindowPos(w.hwnd, 0, x, y, width, height, swpStyle)
+	windows.SetWindowPos(w.hwnd, hwndAfter, x, y, width, height, swpStyle)
 	windows.SetWindowLong(w.hwnd, windows.GWL_STYLE, style)
 	windows.ShowWindow(w.hwnd, showMode)
 }
@@ -909,19 +929,15 @@ func (w *window) Perform(acts system.Action) {
 			y := (mi.Bottom - mi.Top - dy) / 2
 			windows.SetWindowPos(w.hwnd, 0, x, y, dx, dy, windows.SWP_NOZORDER|windows.SWP_FRAMECHANGED)
 		case system.ActionRaise:
-			w.raise()
+			windows.SetForegroundWindow(w.hwnd)
+			windows.SetWindowPos(w.hwnd, windows.HWND_TOP, 0, 0, 0, 0,
+				windows.SWP_NOMOVE|windows.SWP_NOSIZE|windows.SWP_SHOWWINDOW)
 		case system.ActionClose:
 			windows.PostMessage(w.hwnd, windows.WM_CLOSE, 0, 0)
 		}
 	})
 }
 
-func (w *window) raise() {
-	windows.SetForegroundWindow(w.hwnd)
-	windows.SetWindowPos(w.hwnd, windows.HWND_TOPMOST, 0, 0, 0, 0,
-		windows.SWP_NOMOVE|windows.SWP_NOSIZE|windows.SWP_SHOWWINDOW)
-}
-
 func convertKeyCode(code uintptr) (key.Name, bool) {
 	if '0' <= code && code <= '9' || 'A' <= code && code <= 'Z' {
 		return key.Name(rune(code)), true

app/window.go

@@ -439,6 +439,7 @@ func (c *callbacks) EditorState() editorState {
 
 func (c *callbacks) SetComposingRegion(r key.Range) {
 	c.w.imeState.compose = r
+	c.w.driver.ProcessEvent(key.CompositionEvent(r))
 }
 
 func (c *callbacks) EditorInsert(text string) {
@@ -971,7 +972,7 @@ func Decorated(enabled bool) Option {
 
 // TopMost windows will be rendered above all other non-top-most windows.
 //
-// TopMost windows are only supported on MacOS currently.
+// TopMost windows are supported on macOS, Windows.
 func TopMost(enabled bool) Option {
 	return func(_ unit.Metric, cnf *Config) {
 		cnf.TopMost = enabled

io/input/router.go

@@ -419,7 +419,7 @@ func (f *filter) Merge(f2 filter) {
 
 func (f *filter) Matches(e event.Event) bool {
 	switch e.(type) {
-	case key.FocusEvent, key.SnippetEvent, key.EditEvent, key.SelectionEvent:
+	case key.FocusEvent, key.SnippetEvent, key.EditEvent, key.SelectionEvent, key.CompositionEvent:
 		return f.focusable
 	default:
 		return f.pointer.Matches(e)
@@ -463,6 +463,13 @@ func (q *Router) processEvent(e event.Event, system bool) {
 			evts = append(evts, taggedEvent{tag: f, event: e})
 		}
 		q.changeState(e, state, evts)
+	case key.CompositionEvent:
+		e = key.CompositionEvent(rangeNorm(key.Range(e)))
+		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 {

io/key/key.go

@@ -77,6 +77,9 @@ type Caret struct {
 // SelectionEvent is generated when an input method changes the selection.
 type SelectionEvent Range
 
+// CompositionEvent is generated when an input method changes the composing range.
+type CompositionEvent Range
+
 // SnippetEvent is generated when the snippet range is updated by an
 // input method.
 type SnippetEvent Range
@@ -243,11 +246,12 @@ func (h InputHintOp) Add(o *op.Ops) {
 	data[1] = byte(h.Hint)
 }
 
-func (EditEvent) ImplementsEvent()      {}
-func (Event) ImplementsEvent()          {}
-func (FocusEvent) ImplementsEvent()     {}
-func (SnippetEvent) ImplementsEvent()   {}
-func (SelectionEvent) ImplementsEvent() {}
+func (EditEvent) ImplementsEvent()        {}
+func (Event) ImplementsEvent()            {}
+func (FocusEvent) ImplementsEvent()       {}
+func (CompositionEvent) ImplementsEvent() {}
+func (SnippetEvent) ImplementsEvent()     {}
+func (SelectionEvent) ImplementsEvent()   {}
 
 func (FocusCmd) ImplementsCommand()        {}
 func (SoftKeyboardCmd) ImplementsCommand() {}

widget/editor.go

@@ -25,6 +25,7 @@ import (
 	"gioui.org/layout"
 	"gioui.org/op"
 	"gioui.org/op/clip"
+	"gioui.org/op/paint"
 	"gioui.org/text"
 	"gioui.org/unit"
 )
@@ -107,8 +108,9 @@ type imeState struct {
 		rng   key.Range
 		caret key.Caret
 	}
-	snippet    key.Snippet
-	start, end int
+	snippet     key.Snippet
+	composition key.Range
+	start, end  int
 }
 
 type maskReader struct {
@@ -398,9 +400,12 @@ func (e *Editor) processKey(gtx layout.Context) (EditorEvent, bool) {
 		case key.FocusEvent:
 			// Reset IME state.
 			e.ime.imeState = imeState{}
+			e.ime.composition = key.Range{Start: -1, End: -1}
 			if ke.Focus && !e.ReadOnly {
 				gtx.Execute(key.SoftKeyboardCmd{Show: true})
 			}
+		case key.CompositionEvent:
+			e.ime.composition = key.Range(ke)
 		case key.Event:
 			if !gtx.Focused(e) || ke.State != key.Press {
 				break
@@ -735,6 +740,7 @@ func (e *Editor) layout(gtx layout.Context, textMaterial, selectMaterial op.Call
 	if e.Len() > 0 {
 		e.paintSelection(gtx, selectMaterial)
 		e.paintText(gtx, textMaterial)
+		e.paintComposition(gtx, textMaterial)
 	}
 	if gtx.Enabled() {
 		e.paintCaret(gtx, textMaterial)
@@ -759,6 +765,28 @@ func (e *Editor) paintText(gtx layout.Context, material op.CallOp) {
 	e.text.PaintText(gtx, material)
 }
 
+func (e *Editor) paintComposition(gtx layout.Context, material op.CallOp) {
+	e.initBuffer()
+	r := e.ime.composition
+	if r.Start == -1 || r.Start == r.End {
+		return
+	}
+	e.text.regions = e.text.Regions(r.Start, r.End, e.text.regions)
+	thickness := max(gtx.Dp(unit.Dp(1)), 1)
+	for _, region := range e.text.regions {
+		y := region.Bounds.Max.Y - max(region.Baseline/3, thickness)
+		underline := image.Rect(region.Bounds.Min.X, y, region.Bounds.Max.X, y+thickness)
+		underline = underline.Intersect(image.Rectangle{Max: e.text.viewSize})
+		if underline.Empty() {
+			continue
+		}
+		stack := clip.Rect(underline).Push(gtx.Ops)
+		material.Add(gtx.Ops)
+		paint.PaintOp{}.Add(gtx.Ops)
+		stack.Pop()
+	}
+}
+
 // paintCaret paints the text glyphs using the provided material to set the fill material
 // of the caret rectangle.
 func (e *Editor) paintCaret(gtx layout.Context, material op.CallOp) {