把圖片轉換成圓形的Android代碼

/**


轉換圖片成圓形
@param bitmap 傳入Bitmap對象
@return
*/
public Bitmap toRoundBitmap(Bitmap bitmap) {
  int width = bitmap.getWidth();
  int height = bitmap.getHeight();
  float roundPx;
  float left, top, right, bottom, dst_left, dst_top, dst_right, dst_bottom;
  if (width <= height) {
  roundPx = width / 2;
  top = 0;
  bottom = width;
  left = 0;
  right = width;
  height = width;
  dst_left = 0;
  dst_top = 0;
  dst_right = width;
  dst_bottom = width;

  } else {
  roundPx = height / 2;
  float clip = (width - height) / 2;
  left = clip;
  right = width - clip;
  top = 0;
  bottom = height;
  width = height;
  dst_left = 0;
  dst_top = 0;
  dst_right = height;
  dst_bottom = height;

  }
  Bitmap output = Bitmap.createBitmap(width,
                                  height, Config.ARGB_8888);

  Canvas canvas = new Canvas(output);
  final int color = 0xff424242;
  final Paint paint = new Paint();
  final Rect src = new Rect((int)left, (int)top, (int)right, (int)bottom);
  final Rect dst = new Rect((int)dst_left, (int)dst_top, (int)dst_right, (int)dst_bottom);
  final RectF rectF = new RectF(dst);
  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, src, dst, paint);
  return output;
}</pre>