Paint Xfermode draws black line on android 2.2

问题

I am trying to erase some part of Image, so I am Creating a custom ImageView, so for erasing, I am using following paint to draw

    mPaint = new Paint();
    mPaint.setAntiAlias(true);
    mPaint.setDither(true);
    mPaint.setColor(Color.TRANSPARENT);
    mPaint.setStyle(Paint.Style.STROKE);
    mPaint.setStrokeJoin(Paint.Join.ROUND);
    mPaint.setStrokeCap(Paint.Cap.ROUND);
    mPaint.setStrokeWidth(30);
    mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));

I am setting XferMode to PorterDuff.Mode.CLEAR to clear the Image which works fine on android 4.1 but when I am testing this on android 2.3 it draws a black line instead of background color, and I also have disabled the Hardware Acceleration,

can someone explain me why this is not working on android 2.3

回答1:

I had similar issues and I fixed it by using Canvas.clipRect before calling super.onDraw(canvas).

This question helped me out: Clip round from image using xfermode in android

来源：https://stackoverflow.com/questions/15200187/paint-xfermode-draws-black-line-on-android-2-2