(Android)处理图片成圆形

Android将一张Bitmap处理成圆形是十分常见的，经常见的场合就是作为用户头像，我们可以Canvas来辅助实现这个功能，代码如下

 public static Bitmap toRoundCorner(Bitmap bitmap, int pixels) {
         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;
     }

pixels即为图片的半径