oh mmy god

backends/x/event.go

@@ -42,6 +42,14 @@ func (sum *scrollSum) add (button xproto.Button, window *Window, state uint16) {
 
 }
 
+func (window *Window) handleExpose (
+	connection *xgbutil.XUtil,
+	event xevent.ExposeEvent,
+) {
+	_ = window.compressExpose(*event.ExposeEvent)
+	window.redrawChildEntirely()
+}
+
 func (window *Window) handleConfigureNotify (
 	connection *xgbutil.XUtil,
 	event xevent.ConfigureNotifyEvent,
@@ -64,9 +72,29 @@ func (window *Window) handleConfigureNotify (
 		window.metrics.height = int(configureEvent.Height)
 		window.reallocateCanvas()
 		window.resizeChildToFit()
+
+		if !window.exposeEventFollows(configureEvent) {
+			window.redrawChildEntirely()
+		}
 	}
 }
 
+func (window *Window) exposeEventFollows (event xproto.ConfigureNotifyEvent) (found bool) {	
+	nextEvents := xevent.Peek(window.backend.connection)
+	if len(nextEvents) > 0 {
+		untypedEvent := nextEvents[0]
+		if untypedEvent.Err == nil {
+			typedEvent, ok :=
+				untypedEvent.Event.(xproto.ConfigureNotifyEvent)
+			
+			if ok && typedEvent.Window == event.Window {
+				return true
+			}
+		}
+	}
+	return false
+}
+
 func (window *Window) modifiersFromState (
 	state uint16,
 ) (
@@ -201,6 +229,32 @@ func (window *Window) handleMotionNotify (
 	}
 }
 
+func (window *Window) compressExpose (
+	firstEvent xproto.ExposeEvent,
+) (
+	lastEvent xproto.ExposeEvent,
+) {
+	window.backend.connection.Sync()
+	xevent.Read(window.backend.connection, false)
+	lastEvent = firstEvent
+	
+	for index, untypedEvent := range xevent.Peek(window.backend.connection) {
+		if untypedEvent.Err != nil { continue }
+		
+		typedEvent, ok := untypedEvent.Event.(xproto.ExposeEvent)
+		if !ok { continue }
+
+		// FIXME: union all areas into the last event
+		if firstEvent.Window == typedEvent.Window {
+			lastEvent = typedEvent
+			defer func (index int) {
+				xevent.DequeueAt(window.backend.connection, index)
+			} (index)
+		}
+	}
+
+	return
+}
 
 func (window *Window) compressConfigureNotify (
 	firstEvent xproto.ConfigureNotifyEvent,

backends/x/window.go

@@ -39,6 +39,7 @@ func (backend *Backend) NewWindow (
 		backend.connection.RootWin(),
 		0, 0, width, height, 0)
 	err = window.xWindow.Listen (
+		xproto.EventMaskExposure,
 		xproto.EventMaskStructureNotify,
 		xproto.EventMaskPointerMotion,
 		xproto.EventMaskKeyPress,
@@ -50,7 +51,9 @@ func (backend *Backend) NewWindow (
 	window.xWindow.WMGracefulClose (func (xWindow *xwindow.Window) {
 		window.Close()
 	})
-	
+
+	xevent.ExposeFun(window.handleExpose).
+		Connect(backend.connection, window.xWindow.Id)
 	xevent.ConfigureNotifyFun(window.handleConfigureNotify).
 		Connect(backend.connection, window.xWindow.Id)
 	xevent.KeyPressFun(window.handleKeyPress).
@@ -108,6 +111,7 @@ func (window *Window) Adopt (child tomo.Element) {
 		})
 		window.resizeChildToFit()
 		window.childMinimumSizeChangeCallback(child.MinimumSize())
+		window.redrawChildEntirely()
 	}
 }
 
@@ -200,12 +204,14 @@ func (window *Window) reallocateCanvas () {
 			window.metrics.width,
 			window.metrics.height))
 	
-	window.xCanvas.XSurfaceSet(window.xWindow.Id)
+	window.xCanvas.CreatePixmap()
 }
 
 func (window *Window) redrawChildEntirely () {
 	data, stride := window.child.Buffer()
+	bounds := window.child.Bounds()
 	window.xCanvas.For (func (x, y int) (c xgraphics.BGRA) {
+		if !(image.Point { x, y }).In(bounds) { return }
 		rgba := data[x + y * stride]
 		c.R, c.G, c.B, c.A = rgba.R, rgba.G, rgba.B, rgba.A
 		return
@@ -235,13 +241,11 @@ func (window *Window) resizeChildToFit () {
 			window.child.Resize (
 				window.metrics.width,
 				window.metrics.height)
-				window.redrawChildEntirely()
 		}
 	} else {
 		window.child.Resize (
 			window.metrics.width,
 			window.metrics.height)
-			window.redrawChildEntirely()
 	}
 	window.skipChildDrawCallback = false
 }
@@ -310,6 +314,9 @@ func (window *Window) pushRegion (region image.Rectangle) {
 	image, ok := window.xCanvas.SubImage(region).(*xgraphics.Image)
 	if ok {
 		image.XDraw()
-		window.xCanvas.XPaint(window.xWindow.Id)
+		image.XExpPaint (
+			window.xWindow.Id,
+			image.Bounds().Min.X,
+			image.Bounds().Min.Y)
 	}
 }