android - 在矩形外填充 Canvas

Question

我想填充 Canvas 上矩形以外的区域。我用

 canvas.drawRect(pTopLeft.x, pTopLeft.y, pBotRight.x, pBotRight.y, paint);

绘制矩形，但无法弄清楚如何在矩形/剪辑之外进行填充。

谢谢 杰夫

Answer 1

感谢 ted 和 trojanfoe - 我想出的最巧妙的解决方案是

    Point pTopLeft = new Point();
    Point pBotRight = new Point();

    //TODO:set x,y for points

    Rect rHole = new Rect(pTopLeft.x, pTopLeft.y, pBotRight.x, pBotRight.y);
    //assume current clip is full canvas
    //put a hole in the current clip
    canvas.clipRect(rHole,  Region.Op.DIFFERENCE);
    //fill with semi-transparent red
    canvas.drawARGB(50, 255, 0, 0);
    //restore full canvas clip for any subsequent operations
    canvas.clipRect(new Rect(0, 0, canvas.getWidth(), canvas.getHeight())
                    , Region.Op.REPLACE);