gioui · inkeliz · Aug 20, 2022
diff --git a/app/internal/windows/windows.go b/app/internal/windows/windows.go
@@ -243,6 +243,7 @@ const (
 	WM_MOUSEMOVE            = 0x0200
 	WM_MOUSEWHEEL           = 0x020A
 	WM_MOUSEHWHEEL          = 0x020E
+	WM_NCACTIVATE           = 0x0086
 	WM_NCHITTEST            = 0x0084
 	WM_PAINT                = 0x000F
 	WM_QUIT                 = 0x0012

diff --git a/app/os_android.go b/app/os_android.go
@@ -552,7 +552,7 @@ 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 >= system.StageRunning {
+	if w.stage >= system.StageInactive {
 		w.draw(env, true)
 	}
 }
@@ -563,7 +563,7 @@ func Java_org_gioui_GioView_onFrameCallback(env *C.JNIEnv, class C.jclass, view
 	if !exist {
 		return
 	}
-	if w.stage < system.StageRunning {
+	if w.stage < system.StageInactive {
 		return
 	}
 	if w.animating {
@@ -596,7 +596,7 @@ func Java_org_gioui_GioView_onWindowInsets(env *C.JNIEnv, class C.jclass, view C
 		left:   int(left),
 		right:  int(right),
 	}
-	if w.stage >= system.StageRunning {
+	if w.stage >= system.StageInactive {
 		w.draw(env, true)
 	}
 }

diff --git a/app/os_macos.go b/app/os_macos.go
@@ -561,6 +561,13 @@ 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 >= system.StageInactive {
+		if focus == 0 {
+			w.setStage(system.StageInactive)
+		} else {
+			w.setStage(system.StageRunning)
+		}
+	}
 	w.SetCursor(w.cursor)
 }
 

diff --git a/app/os_windows.go b/app/os_windows.go
@@ -283,6 +283,14 @@ func windowProc(hwnd syscall.Handle, msg uint32, wParam, lParam uintptr) uintptr
 	case windows.WM_KILLFOCUS:
 		w.focused = false
 		w.w.Event(key.FocusEvent{Focus: false})
+	case windows.WM_NCACTIVATE:
+		if w.stage >= system.StageInactive {
+			if wParam == windows.TRUE {
+				w.setStage(system.StageRunning)
+			} else {
+				w.setStage(system.StageInactive)
+			}
+		}
 	case windows.WM_NCHITTEST:
 		if w.config.Decorated {
 			// Let the system handle it.

diff --git a/app/window.go b/app/window.go
@@ -426,7 +426,7 @@ func (w *Window) driverDefer(f func(d driver)) {
 
 func (w *Window) updateAnimation(d driver) {
 	animate := false
-	if w.stage >= system.StageRunning && w.hasNextFrame {
+	if w.stage >= system.StageInactive && w.hasNextFrame {
 		if dt := time.Until(w.nextFrame); dt <= 0 {
 			animate = true
 		} else {
@@ -826,7 +826,7 @@ func (w *Window) processEvent(d driver, e event.Event) bool {
 	}
 	switch e2 := e.(type) {
 	case system.StageEvent:
-		if e2.Stage < system.StageRunning {
+		if e2.Stage < system.StageInactive {
 			if w.gpu != nil {
 				w.ctx.Lock()
 				w.gpu.Release()
@@ -842,7 +842,7 @@ 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 < system.StageRunning {
+		if w.stage < system.StageInactive {
 			// No drawing if not visible.
 			break
 		}

diff --git a/io/system/system.go b/io/system/system.go
@@ -59,17 +59,24 @@ type StageEvent struct {
 type Stage uint8
 
 const (
-	// StagePaused is the Stage for inactive Windows.
-	// Inactive Windows don't receive FrameEvents.
+	// StagePaused is the stage for windows that have no on-screen representation.
+	// Paused windows don't receive FrameEvent.
 	StagePaused Stage = iota
-	// StateRunning is for active Windows.
+	// 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: