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;

}