app: replace Window.Config with ConfigEvent

Unlike Raise, Close and other fire-and-forget methods on Window,
Config calls driverRun because it needs to wait for the result.
However, driverRun isn't guaranteed to block in all contexts.

This change avoids the synchronization dance altogether by removing the
Config method and introducing a ConfigEvent event. The event also makes
it clear when the configuration changes.

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

app/os.go

@@ -46,6 +46,11 @@ type Config struct {
 	CustomRenderer bool
 }
 
+// ConfigEvent is sent whenever the configuration of a Window changes.
+type ConfigEvent struct {
+	Config Config
+}
+
 func (c *Config) apply(m unit.Metric, options []Option) {
 	for _, o := range options {
 		o(m, c)
@@ -135,9 +140,6 @@ type driver interface {
 	// Configure the window.
 	Configure([]Option)
 
-	// Config returns the current configuration.
-	Config() Config
-
 	// SetCursor updates the current cursor to name.
 	SetCursor(name pointer.CursorName)
 
@@ -187,4 +189,5 @@ func newWindowRendezvous() *windowRendezvous {
 	return wr
 }
 
-func (_ wakeupEvent) ImplementsEvent() {}
+func (wakeupEvent) ImplementsEvent() {}
+func (ConfigEvent) ImplementsEvent() {}

app/os_android.go

@@ -507,8 +507,12 @@ func (w *window) SetAnimating(anim bool) {
 }
 
 func (w *window) draw(sync bool) {
-	width, height := C.ANativeWindow_getWidth(w.win), C.ANativeWindow_getHeight(w.win)
+	size := image.Pt(int(C.ANativeWindow_getWidth(w.win)), int(C.ANativeWindow_getHeight(w.win)))
-	if width == 0 || height == 0 {
+	if size != w.config.Size {
+		w.config.Size = size
+		w.callbacks.Event(ConfigEvent{Config: w.config})
+	}
+	if size.X == 0 || size.Y == 0 {
 		return
 	}
 	const inchPrDp = 1.0 / 160
@@ -516,10 +520,7 @@ func (w *window) draw(sync bool) {
 	w.callbacks.Event(frameEvent{
 		FrameEvent: system.FrameEvent{
 			Now:    time.Now(),
-			Size: image.Point{
+			Size:   w.config.Size,
-				X: int(width),
-				Y: int(height),
-			},
 			Insets: w.insets,
 			Metric: unit.Metric{
 				PxPerDp: ppdp,
@@ -815,13 +816,12 @@ func (w *window) Configure(options []Option) {
 				w.config.Mode = Windowed
 			}
 		}
+		if w.config != prev {
+			w.callbacks.Event(ConfigEvent{Config: w.config})
+		}
 	})
 }
 
-func (w *window) Config() Config {
-	return w.config
-}
-
 func (w *window) Raise() {}
 
 func (w *window) SetCursor(name pointer.CursorName) {

app/os_ios.go

@@ -95,7 +95,6 @@ type window struct {
 
 	visible bool
 	cursor  pointer.CursorName
-	config  Config
 
 	pointerMap []C.CFTypeRef
 }
@@ -271,10 +270,6 @@ func (w *window) WriteClipboard(s string) {
 
 func (w *window) Configure([]Option) {}
 
-func (w *window) Config() Config {
-	return w.config
-}
-
 func (w *window) Raise() {}
 
 func (w *window) SetAnimating(anim bool) {

app/os_js.go

@@ -94,12 +94,12 @@ func newWindow(win *callbacks, options []Option) error {
 	})
 	w.addEventListeners()
 	w.addHistory()
-	w.Configure(options)
 	w.w = win
 
 	go func() {
 		defer w.cleanup()
 		w.w.SetDriver(w)
+		w.Configure(options)
 		w.blur()
 		w.w.Event(system.StageEvent{Stage: system.StageRunning})
 		w.resize()
@@ -528,10 +528,9 @@ func (w *window) Configure(options []Option) {
 		w.config.Orientation = cnf.Orientation
 		w.orientation(cnf.Orientation)
 	}
-}
+	if w.config != prev {
-
+		w.w.Event(ConfigEvent{Config: w.config})
-func (w *window) Config() Config {
+	}
-	return w.config
 }
 
 func (w *window) Raise() {}
@@ -571,8 +570,14 @@ func (w *window) resize() {
 	w.scale = float32(w.window.Get("devicePixelRatio").Float())
 
 	rect := w.cnv.Call("getBoundingClientRect")
-	w.config.Size.X = int(rect.Get("width").Float()) * int(w.scale)
+	size := image.Point{
-	w.config.Size.Y = int(rect.Get("height").Float()) * int(w.scale)
+		X: int(float32(rect.Get("width").Float()) * w.scale),
+		Y: int(float32(rect.Get("height").Float()) * w.scale),
+	}
+	if size != w.config.Size {
+		w.config.Size = size
+		w.w.Event(ConfigEvent{Config: w.config})
+	}
 
 	if vx, vy := w.visualViewport.Get("width"), w.visualViewport.Get("height"); !vx.IsUndefined() && !vy.IsUndefined() {
 		w.inset.X = float32(w.config.Size.X) - float32(vx.Float())*w.scale
@@ -588,18 +593,14 @@ func (w *window) resize() {
 }
 
 func (w *window) draw(sync bool) {
-	width, height, insets, metric := w.getConfig()
+	size, insets, metric := w.getConfig()
-	if metric == (unit.Metric{}) || width == 0 || height == 0 {
+	if metric == (unit.Metric{}) || size.X == 0 || size.Y == 0 {
 		return
 	}
-
 	w.w.Event(frameEvent{
 		FrameEvent: system.FrameEvent{
 			Now:    time.Now(),
-			Size: image.Point{
+			Size:   size,
-				X: width,
-				Y: height,
-			},
 			Insets: insets,
 			Metric: metric,
 		},
@@ -607,8 +608,8 @@ func (w *window) draw(sync bool) {
 	})
 }
 
-func (w *window) getConfig() (int, int, system.Insets, unit.Metric) {
+func (w *window) getConfig() (image.Point, system.Insets, unit.Metric) {
-	return w.config.Size.X, w.config.Size.Y, system.Insets{
+	return image.Pt(w.config.Size.X, w.config.Size.Y), system.Insets{
 			Bottom: unit.Px(w.inset.Y),
 			Right:  unit.Px(w.inset.X),
 		}, unit.Metric{

app/os_macos.go

@@ -252,10 +252,9 @@ func (w *window) Configure(options []Option) {
 			C.toggleFullScreen(w.window)
 		}
 	}
-}
+	if w.config != prev {
-
+		w.w.Event(ConfigEvent{Config: w.config})
-func (w *window) Config() Config {
+	}
-	return w.config
 }
 
 func (w *window) SetCursor(name pointer.CursorName) {
@@ -389,20 +388,23 @@ func gio_onChangeScreen(view C.CFTypeRef, did uint64) {
 func (w *window) draw() {
 	w.scale = float32(C.getViewBackingScale(w.view))
 	wf, hf := float32(C.viewWidth(w.view)), float32(C.viewHeight(w.view))
-	if wf == 0 || hf == 0 {
+	sz := image.Point{
+		X: int(wf*w.scale + .5),
+		Y: int(hf*w.scale + .5),
+	}
+	if sz != w.config.Size {
+		w.config.Size = sz
+		w.w.Event(ConfigEvent{Config: w.config})
+	}
+	if sz.X == 0 || sz.Y == 0 {
 		return
 	}
-	width := int(wf*w.scale + .5)
-	height := int(hf*w.scale + .5)
 	cfg := configFor(w.scale)
 	w.setStage(system.StageRunning)
 	w.w.Event(frameEvent{
 		FrameEvent: system.FrameEvent{
 			Now:    time.Now(),
-			Size: image.Point{
+			Size:   w.config.Size,
-				X: width,
-				Y: height,
-			},
 			Metric: cfg,
 		},
 		Sync: true,

app/os_wayland.go

@@ -187,6 +187,8 @@ type window struct {
 	serial   C.uint32_t
 	newScale bool
 	scale    int
+	// size is the unscaled window size (unlike config.Size which is scaled).
+	size   image.Point
 	config Config
 
 	wakeups chan struct{}
@@ -222,7 +224,7 @@ func init() {
 	wlDriver = newWLWindow
 }
 
-func newWLWindow(window *callbacks, options []Option) error {
+func newWLWindow(callbacks *callbacks, options []Option) error {
 	d, err := newWLDisplay()
 	if err != nil {
 		return err
@@ -232,10 +234,14 @@ func newWLWindow(window *callbacks, options []Option) error {
 		d.destroy()
 		return err
 	}
-	w.w = window
+	w.w = callbacks
 	go func() {
 		defer d.destroy()
 		defer w.destroy()
+		// Finish and commit setup from createNativeWindow.
+		w.Configure(options)
+		C.wl_surface_commit(w.surf)
+
 		w.w.SetDriver(w)
 		if err := w.loop(); err != nil {
 			panic(err)
@@ -356,15 +362,12 @@ func (d *wlDisplay) createNativeWindow(options []Option) (*window, error) {
 	C.xdg_surface_add_listener(w.wmSurf, &C.gio_xdg_surface_listener, unsafe.Pointer(w.surf))
 	C.xdg_toplevel_add_listener(w.topLvl, &C.gio_xdg_toplevel_listener, unsafe.Pointer(w.surf))
 
-	w.Configure(options)
-
 	if d.decor != nil {
 		// Request server side decorations.
 		w.decor = C.zxdg_decoration_manager_v1_get_toplevel_decoration(d.decor, w.topLvl)
 		C.zxdg_toplevel_decoration_v1_set_mode(w.decor, C.ZXDG_TOPLEVEL_DECORATION_V1_MODE_SERVER_SIDE)
 	}
 	w.updateOpaqueRegion()
-	C.wl_surface_commit(w.surf)
 	return w, nil
 }
 
@@ -487,8 +490,7 @@ func gio_onToplevelClose(data unsafe.Pointer, topLvl *C.struct_xdg_toplevel) {
 func gio_onToplevelConfigure(data unsafe.Pointer, topLvl *C.struct_xdg_toplevel, width, height C.int32_t, states *C.struct_wl_array) {
 	w := callbackLoad(data).(*window)
 	if width != 0 && height != 0 {
-		w.config.Size.X = int(width)
+		w.size = image.Pt(int(width), int(height))
-		w.config.Size.Y = int(height)
 		w.updateOpaqueRegion()
 	}
 }
@@ -855,7 +857,7 @@ func (w *window) flushFling() {
 	w.fling.xExtrapolation = fling.Extrapolation{}
 	w.fling.yExtrapolation = fling.Extrapolation{}
 	vel := float32(math.Sqrt(float64(estx.Velocity*estx.Velocity + esty.Velocity*esty.Velocity)))
-	_, _, c := w.getConfig()
+	_, c := w.getConfig()
 	if !w.fling.anim.Start(c, time.Now(), vel) {
 		return
 	}
@@ -908,11 +910,12 @@ func (w *window) WriteClipboard(s string) {
 }
 
 func (w *window) Configure(options []Option) {
-	_, _, cfg := w.getConfig()
+	_, cfg := w.getConfig()
 	prev := w.config
 	cnf := w.config
 	cnf.apply(cfg, options)
 	if prev.Size != cnf.Size {
+		w.size = image.Pt(cnf.Size.X/w.scale, cnf.Size.Y/w.scale)
 		w.config.Size = cnf.Size
 	}
 	if prev.Title != cnf.Title {
@@ -921,10 +924,9 @@ func (w *window) Configure(options []Option) {
 		C.xdg_toplevel_set_title(w.topLvl, title)
 		C.free(unsafe.Pointer(title))
 	}
-}
+	if w.config != prev {
-
+		w.w.Event(ConfigEvent{Config: w.config})
-func (w *window) Config() Config {
+	}
-	return w.config
 }
 
 func (w *window) Raise() {}
@@ -1374,7 +1376,7 @@ func (w *window) onPointerMotion(x, y C.wl_fixed_t, t C.uint32_t) {
 
 func (w *window) updateOpaqueRegion() {
 	reg := C.wl_compositor_create_region(w.disp.compositor)
-	C.wl_region_add(reg, 0, 0, C.int32_t(w.config.Size.X), C.int32_t(w.config.Size.Y))
+	C.wl_region_add(reg, 0, 0, C.int32_t(w.size.X), C.int32_t(w.size.Y))
 	C.wl_surface_set_opaque_region(w.surf, reg)
 	C.wl_region_destroy(reg)
 }
@@ -1404,9 +1406,9 @@ func (w *window) updateOutputs() {
 	}
 }
 
-func (w *window) getConfig() (int, int, unit.Metric) {
+func (w *window) getConfig() (image.Point, unit.Metric) {
-	width, height := w.config.Size.X*w.scale, w.config.Size.Y*w.scale
+	size := w.size.Mul(w.scale)
-	return width, height, unit.Metric{
+	return size, unit.Metric{
 		PxPerDp: w.ppdp * float32(w.scale),
 		PxPerSp: w.ppsp * float32(w.scale),
 	}
@@ -1419,7 +1421,11 @@ func (w *window) draw(sync bool) {
 	if dead || (!anim && !sync) {
 		return
 	}
-	width, height, cfg := w.getConfig()
+	size, cfg := w.getConfig()
+	if size != w.config.Size {
+		w.config.Size = size
+		w.w.Event(ConfigEvent{Config: w.config})
+	}
 	if cfg == (unit.Metric{}) {
 		return
 	}
@@ -1431,10 +1437,7 @@ func (w *window) draw(sync bool) {
 	w.w.Event(frameEvent{
 		FrameEvent: system.FrameEvent{
 			Now:    time.Now(),
-			Size: image.Point{
+			Size:   w.config.Size,
-				X: width,
-				Y: height,
-			},
 			Metric: cfg,
 		},
 		Sync: sync,
@@ -1458,12 +1461,12 @@ func (w *window) surface() (*C.struct_wl_surface, int, int) {
 		C.xdg_surface_ack_configure(w.wmSurf, w.serial)
 		w.needAck = false
 	}
-	width, height, scale := w.config.Size.X, w.config.Size.Y, w.scale
 	if w.newScale {
-		C.wl_surface_set_buffer_scale(w.surf, C.int32_t(scale))
+		C.wl_surface_set_buffer_scale(w.surf, C.int32_t(w.scale))
 		w.newScale = false
 	}
-	return w.surf, width * scale, height * scale
+	sz, _ := w.getConfig()
+	return w.surf, sz.X, sz.Y
 }
 
 func (w *window) ShowTextInput(show bool) {}

app/os_windows.go

@@ -428,20 +428,23 @@ func (w *window) setStage(s system.Stage) {
 func (w *window) draw(sync bool) {
 	var r windows.Rect
 	windows.GetClientRect(w.hwnd, &r)
-	w.config.Size.X = int(r.Right - r.Left)
+	size := image.Point{
-	w.config.Size.Y = int(r.Bottom - r.Top)
+		X: int(r.Right - r.Left),
+		Y: int(r.Bottom - r.Top),
+	}
 	if w.config.Size.X == 0 || w.config.Size.Y == 0 {
 		return
 	}
+	if size != w.config.Size {
+		w.config.Size = size
+		w.w.Event(ConfigEvent{Config: w.config})
+	}
 	dpi := windows.GetWindowDPI(w.hwnd)
 	cfg := configForDPI(dpi)
 	w.w.Event(frameEvent{
 		FrameEvent: system.FrameEvent{
 			Now:    time.Now(),
-			Size: image.Point{
+			Size:   w.config.Size,
-				X: w.config.Size.X,
-				Y: w.config.Size.Y,
-			},
 			Metric: cfg,
 		},
 		Sync: sync,
@@ -531,10 +534,9 @@ func (w *window) Configure(options []Option) {
 	if prev.Mode != cnf.Mode {
 		w.SetWindowMode(cnf.Mode)
 	}
-}
+	if w.config != prev {
-
+		w.w.Event(ConfigEvent{Config: w.config})
-func (w *window) Config() Config {
+	}
-	return w.config
 }
 
 func (w *window) SetWindowMode(mode WindowMode) {

app/os_x11.go

@@ -161,10 +161,9 @@ func (w *x11Window) Configure(options []Option) {
 	if prev.Mode != cnf.Mode {
 		w.SetWindowMode(cnf.Mode)
 	}
-}
+	if w.config != prev {
-
+		w.w.Event(ConfigEvent{Config: w.config})
-func (w *x11Window) Config() Config {
+	}
-	return w.config
 }
 
 func (w *x11Window) Raise() {
@@ -356,10 +355,7 @@ loop:
 			w.w.Event(frameEvent{
 				FrameEvent: system.FrameEvent{
 					Now:    time.Now(),
-					Size: image.Point{
+					Size:   w.config.Size,
-						X: w.config.Size.X,
-						Y: w.config.Size.Y,
-					},
 					Metric: w.metric,
 				},
 				Sync: syn,
@@ -516,7 +512,10 @@ func (h *x11EventHandler) handleEvents() bool {
 			w.w.Event(key.FocusEvent{Focus: false})
 		case C.ConfigureNotify: // window configuration change
 			cevt := (*C.XConfigureEvent)(unsafe.Pointer(xev))
-			w.config.Size = image.Pt(int(cevt.width), int(cevt.height))
+			if sz := image.Pt(int(cevt.width), int(cevt.height)); sz != w.config.Size {
+				w.config.Size = sz
+				w.w.Event(ConfigEvent{Config: w.config})
+			}
 			// redraw will be done by a later expose event
 		case C.SelectionNotify:
 			cevt := (*C.XSelectionEvent)(unsafe.Pointer(xev))

app/window.go

@@ -263,17 +263,6 @@ func (w *Window) Option(opts ...Option) {
 	})
 }
 
-// Config returns the Window configuration.
-//
-// A FrameEvent will occur whenever the configuration changes.
-func (w *Window) Config() Config {
-	var cnf Config
-	w.driverRun(func(d driver) {
-		cnf = d.Config()
-	})
-	return cnf
-}
-
 // ReadClipboard initiates a read of the clipboard in the form
 // of a clipboard.Event. Multiple reads may be coalesced
 // to a single event.