android：canvas绘制一个透明矩形并填充其余区域

如何解决android：canvas绘制一个透明矩形并填充其余区域

我为有需要的人共享一个代码，该代码用于绘制相机的SurfaceView，该代码由透明背景上的透明矩形和可选的alpha组成。

欢迎大家做出更好的贡献：）

@Override
protected void onDraw(Canvas canvas) {
    mAGPLog.e(this.getClass().getName() + " - onDraw");

    canvas.drawColor(Color.argb(128,224,224));

    int margin = (int) getResources().getDimension(R.dimen.margin_camera);
    int width = getWidth();
    int height = getHeight();
    mAGPLog.e("width - " + width + " * height - " + height);

    int distance = width < height ? width - margin : height - margin;
    paint.setColor(Color.CYAN);
    paint.setstrokeWidth(strokerWidth);
    paint.setStyle(Paint.Style.stroke);
    canvas.drawRect(
            (width - distance) / 2,(height - distance) / 2,(width + distance) / 2,(height + distance) / 2,paint);

    paint.setStyle(Paint.Style.FILL);
    paint.setColor(Color.argb(0,255,255));
    paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
    canvas.drawRect(
            (width - distance) / 2 + strokerWidth,(height - distance) / 2 + strokerWidth,(width + distance) / 2 - strokerWidth,(height + distance) / 2 - strokerWidth,paint);
    super.onDraw(canvas);
}