android 将图片变为圆角

/**
* 图片变为圆角
* @param bitmap:传入的bitmap
* @param pixels：圆角的度数，值越大，圆角越大
* @return bitmap:加入圆角的bitmap
*/
public static Bitmap toRoundCorner(Bitmap bitmap, int pixels) {
if(bitmap == null) {
return null;
}
Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Config.ARGB_8888);
Canvas canvas = new Canvas(output);
final int color = 0xff424242;
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
final RectF rectF = new RectF(rect);
final float roundPx = pixels;
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(bitmap, rect, rect, paint);
return output;
}