ui: Add SetWindowFloating / IsWindowFloating

Fixes #880

examples/windowsize/main.go

@@ -58,6 +58,7 @@ var (
 	flagWindowPosition    = flag.String("windowposition", "", "window position (e.g., 100,200)")
 	flagScreenTransparent = flag.Bool("screentransparent", false, "screen transparent")
 	flagAutoAdjusting     = flag.Bool("autoadjusting", false, "make the game screen auto-adjusting")
+	flagFloating          = flag.Bool("floating", false, "make the window floating")
 )
 
 func init() {
@@ -137,6 +138,7 @@ func (g *game) Update(screen *ebiten.Image) error {
 	decorated := ebiten.IsWindowDecorated()
 	positionX, positionY := ebiten.WindowPosition()
 	transparent := ebiten.IsScreenTransparent()
+	floating := ebiten.IsWindowFloating()
 	resizable := ebiten.IsWindowResizable()
 
 	const d = 16
@@ -218,6 +220,9 @@ func (g *game) Update(screen *ebiten.Image) error {
 	if inpututil.IsKeyJustPressed(ebiten.KeyD) {
 		decorated = !decorated
 	}
+	if inpututil.IsKeyJustPressed(ebiten.KeyL) {
+		floating = !floating
+	}
 	if inpututil.IsKeyJustPressed(ebiten.KeyR) {
 		resizable = !resizable
 	}
@@ -239,6 +244,7 @@ func (g *game) Update(screen *ebiten.Image) error {
 	ebiten.SetMaxTPS(tps)
 	ebiten.SetWindowDecorated(decorated)
 	ebiten.SetWindowPosition(positionX, positionY)
+	ebiten.SetWindowFloating(floating)
 	if !*flagLegacy {
 		// A resizable window is available only with RunGame.
 		ebiten.SetWindowResizable(resizable)
@@ -294,6 +300,7 @@ Press I key to change the window icon (only for desktops)
 Press V key to switch vsync
 Press T key to switch TPS (ticks per second)
 Press D key to switch the window decoration (only for desktops)
+Press L key to switch the window floating state (only for desktops)
 %s
 IsForeground?: %s
 Windows Position: (%d, %d)
@@ -363,6 +370,9 @@ func main() {
 	if *flagFullscreen {
 		ebiten.SetFullscreen(true)
 	}
+	if *flagFloating {
+		ebiten.SetWindowFloating(true)
+	}
 	if *flagAutoAdjusting {
 		if *flagLegacy {
 			log.Println("-autoadjusting flag cannot work with -legacy flag")

internal/driver/ui.go

@@ -68,6 +68,9 @@ type Window interface {
 	Size() (int, int)
 	SetSize(width, height int)
 
+	IsFloating() bool
+	SetFloating(floating bool)
+
 	SetIcon(iconImages []image.Image)
 	SetTitle(title string)
 }

internal/glfw/const.go

@@ -77,6 +77,7 @@ const (
 	ContextVersionMajor    = Hint(0x00022002)
 	ContextVersionMinor    = Hint(0x00022003)
 	Decorated              = Hint(0x00020005)
+	Floating               = Hint(0x00020007)
 	Focused                = Hint(0x00020001)
 	Resizable              = Hint(0x00020003)
 	TransparentFramebuffer = Hint(0x0002000A)

internal/uidriver/glfw/ui.go

@@ -66,6 +66,7 @@ type UserInterface struct {
 	initWindowPositionYInDP  int
 	initWindowWidthInDP      int
 	initWindowHeightInDP     int
+	initWindowFloating       bool
 	initScreenTransparent    bool
 	initIconImages           []image.Image
 
@@ -334,6 +335,19 @@ func (u *UserInterface) setInitWindowSize(width, height int) {
 	u.m.Unlock()
 }
 
+func (u *UserInterface) isInitWindowFloating() bool {
+	u.m.Lock()
+	f := u.initWindowFloating
+	u.m.Unlock()
+	return f
+}
+
+func (u *UserInterface) setInitWindowFloating(floating bool) {
+	u.m.Lock()
+	u.initWindowFloating = floating
+	u.m.Unlock()
+}
+
 // toDeviceIndependentPixel must be called from the main thread.
 func (u *UserInterface) toDeviceIndependentPixel(x float64) float64 {
 	return x / u.glfwScale()
@@ -628,6 +642,12 @@ func (u *UserInterface) run(context driver.UIContext) error {
 		}
 		glfw.WindowHint(glfw.Resizable, resizable)
 
+		floating := glfw.False
+		if u.isInitWindowFloating() {
+			floating = glfw.True
+		}
+		glfw.WindowHint(glfw.Floating, floating)
+
 		// Set the window visible explicitly or the application freezes on Wayland (#974).
 		if os.Getenv("WAYLAND_DISPLAY") != "" {
 			glfw.WindowHint(glfw.Visible, glfw.True)

internal/uidriver/glfw/window.go

@@ -89,6 +89,33 @@ func (w *window) SetResizable(resizable bool) {
 	})
 }
 
+func (w *window) IsFloating() bool {
+	if !w.ui.isRunning() {
+		return w.ui.isInitWindowFloating()
+	}
+	var v bool
+	_ = w.ui.t.Call(func() error {
+		v = w.ui.window.GetAttrib(glfw.Floating) == glfw.True
+		return nil
+	})
+	return v
+}
+
+func (w *window) SetFloating(floating bool) {
+	if !w.ui.isRunning() {
+		w.ui.setInitWindowFloating(floating)
+		return
+	}
+	_ = w.ui.t.Call(func() error {
+		v := glfw.False
+		if floating {
+			v = glfw.True
+		}
+		w.ui.window.SetAttrib(glfw.Floating, v)
+		return nil
+	})
+}
+
 func (w *window) Position() (int, int) {
 	if !w.ui.isRunning() {
 		panic("glfw: WindowPosition can't be called before the main loop starts")

window.go

@@ -25,6 +25,16 @@ const (
 	invalidPos = minInt
 )
 
+// IsWindowDecorated reports whether the window is decorated.
+//
+// IsWindowDecorated is concurrent-safe.
+func IsWindowDecorated() bool {
+	if w := uiDriver().Window(); w != nil {
+		return w.IsDecorated()
+	}
+	return false
+}
+
 // SetWindowDecorated sets the state if the window is decorated.
 //
 // The window is decorated by default.
@@ -39,16 +49,6 @@ func SetWindowDecorated(decorated bool) {
 	}
 }
 
-// IsWindowDecorated reports whether the window is decorated.
-//
-// IsWindowDecorated is concurrent-safe.
-func IsWindowDecorated() bool {
-	if w := uiDriver().Window(); w != nil {
-		return w.IsDecorated()
-	}
-	return false
-}
-
 // IsWindowResizable reports whether the window is resizable by the user's dragging on desktops.
 // On the other environments, IsWindowResizable always returns false.
 //
@@ -233,3 +233,22 @@ func SetWindowSize(width, height int) {
 		w.SetSize(width, height)
 	}
 }
+
+// IsWindowFloating reports whether the window is always shown above all the other windows.
+//
+// IsWindowFloating is concurrent-safe.
+func IsWindowFloating() bool {
+	if w := uiDriver().Window(); w != nil {
+		return w.IsFloating()
+	}
+	return false
+}
+
+// SetWindowFloating sets the state whether the window is always shown above all the other windows.
+//
+// SetWindowFloating is concurrent-safe.
+func SetWindowFloating(float bool) {
+	if w := uiDriver().Window(); w != nil {
+		w.SetFloating(float)
+	}
+}