I forgor to commit all this stuff

canvas/canvas.go

@@ -3,6 +3,7 @@ package xcanvas
 import "image"
 import "image/color"
 import "github.com/jezek/xgbutil"
+import "github.com/jezek/xgb/xproto"
 import "git.tebibyte.media/tomo/ggfx"
 import "github.com/jezek/xgbutil/xgraphics"
 import "git.tebibyte.media/tomo/tomo/canvas"
@@ -36,10 +37,16 @@ func (this Canvas) Pen () canvas.Pen {
 }
 
 // Clip returns a sub-canvas of this canvas.
-func (this Canvas) Clip (bounds image.Rectangle) Canvas {
+func (this Canvas) Clip (bounds image.Rectangle) canvas.Canvas {
 	return Canvas { this.Image.SubImage(bounds).(*xgraphics.Image) }
 }
 
+// Push pushes this canvas to the screen.
+func (this Canvas) Push (window xproto.Window) {
+	this.XDraw()
+	this.XExpPaint(window, this.Bounds().Min.X, this.Bounds().Min.Y)
+}
+
 // TODO: we need to implement:
 //  - cap
 //  - joint