public void drawCW(Bitmap bitmap, int xo, int yo) {
		for (int y = 0; y < bitmap.width; y++) {
			int yy = y + yo;
			if (yy < 0 || yy >= this.height)
				continue;
			for (int x = 0; x < bitmap.height; x++) {
				int xx = bitmap.height - x + xo;
				if (xx < 0 || xx >= this.width)
					continue;
				int color = bitmap.pixels[y + x * bitmap.width];
				if (color < 0)
					pixels[xx + yy * this.width] = color;
			}
		}
	}