java旋转图片

    /**
     * 旋转角度
     * @param src 源图片
     * @param angel 角度
     * @return 目标图片
     */
    public static BufferedImage rotate(Image src, int angel) {
        int src_width = src.getWidth(null);
        int src_height = src.getHeight(null);
        // calculate the new image size
        Rectangle rect_des = CalcRotatedSize(new Rectangle(new Dimension(
                src_width, src_height)), angel);

        BufferedImage res = null;
        res = new BufferedImage(rect_des.width, rect_des.height,
                BufferedImage.TYPE_INT_RGB);
        Graphics2D g2 = res.createGraphics();
        // transform
        g2.translate((rect_des.width - src_width) / 2, (rect_des.height - src_height) / 2); //平移
        g2.rotate(Math.toRadians(angel), src_width / 2, src_height / 2); //旋转

        g2.drawImage(src, null, null);
        return res;
    }

    /**
     * 计算转换后目标矩形的宽高
     * @param src 源矩形
     * @param angel 角度
     * @return 目标矩形
     */
    private static Rectangle CalcRotatedSize(Rectangle src, int angel) {
        double cos = Math.abs(Math.cos(Math.toRadians(angel)));
        double sin = Math.abs(Math.sin(Math.toRadians(angel)));
        int des_width = (int)(src.width *  cos) + (int)(src.height * sin);
        int des_height =  (int)(src.height *  cos) + (int)(src.width * sin);
        return new java.awt.Rectangle(new Dimension(des_width, des_height));
    }