OpenCV函數cv2DRotationMatrix實現圖像旋轉

OpenCV函數cv2DRotationMatrix實現圖像旋轉

#include <cv.h>
#include <highgui.h>

#pragma comment(lib, "cv.lib")
#pragma comment(lib, "cxcore.lib")
#pragma comment(lib, "highgui.lib")

int main()
{
 double degree = 30; // rotate 30 degree
 double angle = degree  * CV_PI / 180.; // angle in radian
 double a = sin(angle), b = cos(angle); // sine and cosine of angle

 // Load source image as you wish
 IplImage *imgSrc = cvLoadImage("test.png");
 int w_src = imgSrc->width;
 int h_src = imgSrc->height;
 cvNamedWindow ("src", 1);
 cvShowImage ("src", imgSrc);
 // Make w_dst and h_dst to fit the output image
 int w_dst = int(h_src * fabs(a) + w_src * fabs(b));
 int h_dst = int(w_src * fabs(a) + h_src * fabs(b));

 // map matrix for WarpAffine, stored in statck array
 double map[6];
 CvMat map_matrix = cvMat(2, 3, CV_64FC1, map);

 // Rotation center needed for cv2DRotationMatrix
 CvPoint2D32f pt = cvPoint2D32f(w_src / 2, h_src / 2);
 cv2DRotationMatrix(pt, degree, 1.0, &map_matrix);

 // Adjust rotation center to dst's center,
 // otherwise you will get only part of the result
 map[2] += (w_dst - w_src) / 2;
 map[5] += (h_dst - h_src) / 2;

 // We need a destination image

 IplImage *imgDst = cvCreateImage(cvSize(w_dst, h_dst), 8, 3);
 cvWarpAffine(
  imgSrc,
  imgDst,
  &map_matrix,
  CV_INTER_LINEAR | CV_WARP_FILL_OUTLIERS,
  cvScalarAll(0)
  );

 // Don't forget to release imgSrc and imgDst if you no longer need them
 cvNamedWindow( "dst_big", 1 );
 cvShowImage( "dst_big", imgDst);

 cvWaitKey(0);
 cvReleaseImage(&imgSrc);
 cvReleaseImage(&imgDst);
 return 0;
}

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