protected override void onDraw (Canvas canvas)
{
canvas.drawColor (Color.GRAY);
canvas.save ();
canvas.translate (10, 10);
drawScene (canvas);
canvas.restore ();
canvas.save ();
canvas.translate (160, 10);
canvas.clipRect (10, 10, 90, 90);
canvas.clipRect (30, 30, 70, 70, Region.Op.DIFFERENCE);
drawScene (canvas);
canvas.restore ();
canvas.save ();
canvas.translate (10, 160);
mPath.reset ();
canvas.clipPath (mPath); // makes the clip empty
mPath.addCircle (50, 50, 50, Path.Direction.CCW);
canvas.clipPath (mPath, Region.Op.REPLACE);
drawScene (canvas);
canvas.restore ();
canvas.save ();
canvas.translate (160, 160);
canvas.clipRect (0, 0, 60, 60);
canvas.clipRect (40, 40, 100, 100, Region.Op.UNION);
drawScene (canvas);
canvas.restore ();
canvas.save ();
canvas.translate (10, 310);
canvas.clipRect (0, 0, 60, 60);
canvas.clipRect (40, 40, 100, 100, Region.Op.XOR);
drawScene (canvas);
canvas.restore ();
canvas.save ();
canvas.translate (160, 310);
canvas.clipRect (0, 0, 60, 60);
canvas.clipRect (40, 40, 100, 100, Region.Op.REVERSE_DIFFERENCE);
drawScene (canvas);
canvas.restore ();
}