Android实现图片转换成圆形

/**      * 转换图片成圆形      *       * @param bitmap      *            传入Bitmap对象      * @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;              left = 0;              top = 0;              right = width;              bottom = 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);// 设置画笔无锯齿          canvas.drawARGB(0, 0, 0, 0); // 填充整个Canvas          paint.setColor(color);          // 以下有两种方法画圆,drawRounRect和drawCircle          // canvas.drawRoundRect(rectF, roundPx, roundPx, paint);// 画圆角矩形，第一个参数为图形显示区域，第二个参数和第三个参数分别是水平圆角半径和垂直圆角半径。          canvas.drawCircle(roundPx, roundPx, roundPx, paint);          paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));// 设置两张图片相交时的模式,参考http://trylovecatch.iteye.com/blog/1189452          canvas.drawBitmap(bitmap, src, dst, paint); //以Mode.SRC_IN模式合并bitmap和已经draw了的Circle          return output;      }