工具类-base64图片旋转返回

base64 图片旋转实现

public final class Base64ImageUtil {


    private 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();
        res = g2.getDeviceConfiguration().createCompatibleImage(rect_des.width, rect_des.height, Transparency.TRANSLUCENT);
        g2.dispose();
        g2 = res.createGraphics();
        // transform
        g2.translate((rect_des.width - src_width) / 2,
                (rect_des.height - src_height) / 2);
        g2.rotate(Math.toRadians(angel), src_width / 2, src_height / 2);
        g2.setColor(new Color(255,0,0));
        g2.setStroke(new BasicStroke(1));
        g2.drawImage(src, null, null);
        g2.dispose();
        return res;
    }

    public static Rectangle CalcRotatedSize(Rectangle src, int angel) {
        // if angel is greater than 90 degree, we need to do some conversion
        if (angel >= 90) {
            if(angel / 90 % 2 == 1){
                int temp = src.height;
                src.height = src.width;
                src.width = temp;
            }
            angel = angel % 90;
        }

        double r = Math.sqrt(src.height * src.height + src.width * src.width) / 2;
        double len = 2 * Math.sin(Math.toRadians(angel) / 2) * r;
        double angel_alpha = (Math.PI - Math.toRadians(angel)) / 2;
        double angel_dalta_width = Math.atan((double) src.height / src.width);
        double angel_dalta_height = Math.atan((double) src.width / src.height);

        int len_dalta_width = (int) (len * Math.cos(Math.PI - angel_alpha
                - angel_dalta_width));
        int len_dalta_height = (int) (len * Math.cos(Math.PI - angel_alpha
                - angel_dalta_height));
        int des_width = src.width + len_dalta_width * 2;
        int des_height = src.height + len_dalta_height * 2;
        return new Rectangle(new Dimension(des_width, des_height));
    }

    /**
     * 顺时针旋转
     * @param base64FileStr
     * @param rotate
     * @return
     * @throws IOException
     */
    public static String rotateImage(String base64FileStr,int rotate) throws IOException {
        if(StringUtils.isEmpty(base64FileStr)){
            return "";
        }

        Base64.Decoder decoder = Base64.getDecoder();
        // Base64解码,对字节数组字符串进行Base64解码并生成文件
        final byte[] byt = decoder.decode(base64FileStr);
        for (int i = 0, len = byt.length; i < len; ++i) {
            // 调整异常数据
            if (byt[i] < 0) {
                byt[i] += 256;
            }
        }
        InputStream input = new ByteArrayInputStream(byt);
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        BufferedImage src = ImageIO.read(input);
        BufferedImage des = rotate(src, rotate);
        ImageIO.write(des,"png",out);
        final Base64.Encoder encoder = Base64.getEncoder();
        final byte[] bytes = out.toByteArray();
        return encoder.encodeToString(bytes);
    }



    public static void main(String[] args) throws IOException {
        String base64FileStr = "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";
        final String image = rotateImage(base64FileStr, 270);
        System.out.println(image);
    }


}