java实现图片任意角度旋转

/**
   * 图像旋转
   * @param src
   * @param angel
   * @return
*/
  public static BufferedImage Rotate(Image src, double 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_3BYTE_BGR);
    Graphics2D 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.drawImage(src, null, null);
    return res;
  }
 
  public static Rectangle CalcRotatedSize(Rectangle src, double 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));
    len_dalta_width=len_dalta_width>0?len_dalta_width:-len_dalta_width;
 
    int len_dalta_height = (int) (len * Math.cos(Math.PI - angel_alpha
        - angel_dalta_height));
    len_dalta_height=len_dalta_height>0?len_dalta_height:-len_dalta_height;
 
    int des_width = src.width + len_dalta_width * 2;
    int des_height = src.height + len_dalta_height * 2;
    des_width=des_width>0?des_width:-des_width;
    des_height=des_height>0?des_height:-des_height;
    return new java.awt.Rectangle(new Dimension(des_width, des_height));
}

 /**
   * opencv实现图片旋转
   * @param splitImage
   * @param angle
   * @return
*/
  public static Mat rotate3(Mat splitImage, double angle)
  {
    double thera = angle * Math.PI / 180;
    double a = Math.sin(thera);
    double b = Math.cos(thera);
 
    int wsrc = splitImage.width();
    int hsrc = splitImage.height();
 
    int wdst = (int) (hsrc * Math.abs(a) + wsrc * Math.abs(b));
    int hdst = (int) (wsrc * Math.abs(a) + hsrc * Math.abs(b));
    Mat imgDst = new Mat(hdst, wdst, splitImage.type());
 
    Point pt = new Point(splitImage.cols() / 2, splitImage.rows() / 2);
    // 获取仿射变换矩阵
    Mat affineTrans = Imgproc.getRotationMatrix2D(pt, angle, 1.0);
 
    System.out.println(affineTrans.dump());
    // 改变变换矩阵第三列的值
    affineTrans.put(0, 2, affineTrans.get(0, 2)[0] + (wdst - wsrc) / 2);
    affineTrans.put(1, 2, affineTrans.get(1, 2)[0] + (hdst - hsrc) / 2);
 
    Imgproc.warpAffine(splitImage, imgDst, affineTrans, imgDst.size(),
        Imgproc.INTER_CUBIC | Imgproc.WARP_FILL_OUTLIERS);
    return imgDst;
}