Draw background color in window

backends/x/x.go

@@ -32,6 +32,8 @@ type Backend struct {
 	font struct {
 		face font.Face
 	}
+
+	colors [4]xgraphics.BGRA
 	
 	metrics struct {
 		windowWidth  int
@@ -134,20 +136,7 @@ func (backend *Backend) handleXEvent (event xgb.Event) {
 				backend.compressConfigureNotify(configureEvent)
 		
 			// resize and rebind canvas
-			backend.canvas.Destroy()
+			backend.reallocateCanvas()
-			backend.canvas = xgraphics.New (
-				backend.connection,
-				image.Rect (
-					0, 0,
-					backend.metrics.windowWidth,
-					backend.metrics.windowHeight))
-			// FIXME (?): this doesn't work. if it were to work, it
-			// would possibly be a cleaner way to resize the canvas.
-			// backend.canvas.Scale (
-				// backend.metrics.windowWidth,
-				// backend.metrics.windowHeight)
-			backend.drawRune(8, 16, 'X')
-			backend.bindCanvas()
 		}
 	}
 }
@@ -193,14 +182,32 @@ func (backend *Backend) calculateWindowSize () (x, y int) {
 	return
 }
 
-func (backend *Backend) bindCanvas () {
+func (backend *Backend) reallocateCanvas () {
+	if backend.canvas != nil {
+		backend.canvas.Destroy()
+	}
+	backend.canvas = xgraphics.New (
+		backend.connection,
+		image.Rect (
+			0, 0,
+			backend.metrics.windowWidth,
+			backend.metrics.windowHeight))
+	backend.canvas.For (func (x, y int) xgraphics.BGRA {
+		return backend.colors[stone.ColorApplication]
+	})
+	// FIXME (?): this doesn't work. if it were to work, it
+	// would possibly be a cleaner way to resize the canvas.
+	// backend.canvas.Scale (
+		// backend.metrics.windowWidth,
+		// backend.metrics.windowHeight)
+	backend.drawRune(8, 16, 'X')
 	backend.canvas.XSurfaceSet(backend.window.Id)
 	backend.canvas.XDraw()
 	backend.canvas.XPaint(backend.window.Id)
 }
 
 func (backend *Backend) drawRune (x, y int, character rune) {
-	
+	// bounds, image, point, _, _ :=
 }
 
 // factory instantiates an X backend.
@@ -214,6 +221,22 @@ func factory (application *stone.Application) (output stone.Backend, err error)
 	// TODO: load this from a file
 	backend.font.face = basicfont.Face7x13
 
+	// pre-calculate colors
+	for index := 0; index < len(backend.colors); index ++ {
+		color := backend.config.Color(stone.Color(index))
+		r, g, b, a := color.RGBA()
+		r >>= 8
+		g >>= 8
+		b >>= 8
+		a >>= 8
+		backend.colors[index] = xgraphics.BGRA {
+			R: uint8(r),
+			G: uint8(g),
+			B: uint8(b),
+			A: uint8(a),
+		}
+	}
+
 	// calculate metrics
 	metrics := backend.font.face.Metrics()
 	glyphAdvance, _ := backend.font.face.GlyphAdvance('M')
@@ -246,13 +269,7 @@ func factory (application *stone.Application) (output stone.Backend, err error)
 	backend.SetIcon(application.Icon())
 
 	// create a canvas
-	backend.canvas = xgraphics.New (
+	backend.reallocateCanvas()
-		backend.connection,
-		image.Rect (
-			0, 0,
-			backend.metrics.windowWidth,
-			backend.metrics.windowHeight))
-	backend.bindCanvas()
 
 	// attatch graceful close handler
 	backend.window.WMGracefulClose (func (window *xwindow.Window) {