OpenCV rotate an image at any angle

Reproduced (http://www.cnblogs.com/HappyXie/archive/2011/03/02/1969434.html)//opencv 4 The rotation of the image at any angle

Need the support of inter Company's OPENCV.

OpenCV 4 rotation of an image at any angle
Image to be rotated iplimage* img_old
Returns the rotated image iplimage* img_tmp.
The angle of rotation, the unit degree.
Three different methods. Method Two is not fully tested, method one can meet most of the needs
Iplimage * Fitrotate (iplimage* img_old, double Angle,int method)

{

iplimage* img_tmp = NULL;

Double Anglerad = (cv_pi* (angle/180));
int Newheight =int (fabs ((Sin (anglerad) *img_old->width) + fabs ((cos (anglerad) *img_old->height));
int Newwidth =int (fabs ((Sin (anglerad) *img_old->height) + fabs ((cos (anglerad) *img_old->width));

Img_tmp = Cvcreateimage (Cvsize (newwidth,newheight), ipl_depth_8u, 3);
Cvfillimage (img_tmp,0);//destination image using an extended size

iplimage* DST = cvcloneimage (img_old);//The target image and the original image and other large


float m[6];
Cvmat m = Cvmat (2, 3, cv_32f, M);


if (1==method)
{
Method one extracts pixel quadrilateral, using sub-pixel precision

int w = img_old->width;
int h = img_old->height;

M[0] = (float) (cos (angle*cv_pi/180.));
M[1] = (float) (sin (angle*cv_pi/180.));
M[2] = w*0.5f;
M[3] =-m[1];
M[4] = m[0];
M[5] = h*0.5f;

Cvgetquadranglesubpix (Img_old, DST, &m, 1, cvscalarall (0));

Cvgetquadranglesubpix (Img_old, Img_tmp, &m, Cv_inter_linear, Cvscalarall (0));//+cv_warp_fill_outliers

Method one extracts pixel quadrilateral, using sub-pixel precision
}

if (2==method)
{
Method Two The problem of affine transformation matrix using two-dimensional rotation requires that the input and output images be the same large rotation center is wrong

CVPOINT2D32F Center;
Center.x=float (img_old->width/2.0+0.5);//float (img_tmp->width/2.0+0.5);
Center.y=float (img_old->height/2.0+0.5);//float (img_tmp->height/2.0+0.5);
Cv2drotationmatrix (center, angle,1, &m);

Cvwarpaffine (Img_old, DST, &m,cv_inter_linear,cvscalarall (0));//Small map
Small target image


To extend an image
Can only be treated differently in different quadrants within a certain angle
int Dx=int ((newwidth-img_old->width)/2+0.5);
int Dy=int ((newheight-img_old->height)/2+0.5);

uchar* old_ptr,*temp_ptr;

for (int y=0; yheight; y++)//In order not to cross the border
{