title: Paint Xfermode draws black line on android 2.2
body: <p>I am trying to erase some part of Image, so I am Creating a custom <code>ImageView</code>, so for erasing, I am using following paint to draw</p>
  
  <pre><code>    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));
  </code></pre>
  
  <p>I am setting <code>XferMode</code> to <code>PorterDuff.Mode.CLEAR</code> 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, </p>
  
  <p>can someone explain me why this is not working on android 2.3</p>