IndicationView.java 文件源码

private Bitmap drawCircleBitmap(Bitmap bitmap) {
    Bitmap circleBitmap = Bitmap.createBitmap(getMeasuredWidth(), getMeasuredHeight(), Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(circleBitmap);

    Paint paint = new Paint();
    paint.setDither(true);
    paint.setAntiAlias(true);
    paint.setFilterBitmap(true);

    canvas.drawCircle(getMeasuredWidth() / 2, getMeasuredHeight() / 2, getMeasuredWidth() / 2, paint);
    paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
    canvas.drawBitmap(bitmap, 0, 0, paint);

    bitmap.recycle();

    return circleBitmap;
}