※代码

/**
	 * 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 Paint paint = new Paint();
		final Rect src = http://www.mamicode.com/new Rect((int) left, (int) top, (int) right, (int) bottom);>

※Demo下载
http://download.csdn.net/detail/u010785585/7690145