java实现图片任意角度旋转

本文实例为大家分享了Java实现图片旋转，供大家参考，具体内容如下

方法一：普通方法实现图片旋转

/**
  * 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));
}

方法二：opencv实现图片旋转

/**
  * 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;
}

来源：https://blog.csdn.net/zwl18210851801/article/details/81279622