C++ opencv旋转图片(一)

//opencv
#include "opencv2/opencv.hpp"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp" 

/**************************************************************************************************************
Function:       RotateImage
Description:    旋转图片
Input:          src:需要旋转的图片路径 angle:旋转角度 clockwise:为true则顺时针旋转，否则为逆时针旋转
Return:         旋转后的图片
***************************************************************************************************************/
IplImage* RotateImage(IplImage* src, int angle, bool clockwise)
{
	IplImage* dst = NULL;
	try
	{
		angle = abs(angle) % 180;
		if (angle > 90)
		{
			angle = 90 - (angle % 90);
		}
		
		int width =
			static_cast(src->height * sin(angle * CV_PI / 180.0)) +
			static_cast(src->width * cos(angle * CV_PI / 180.0)) + 1;
		int height =
			static_cast(src->height * cos(angle * CV_PI / 180.0)) +
			static_cast(src->width * sin(angle * CV_PI / 180.0)) + 1;
		int tempLength = static_cast(sqrt(src->width * src->width + src->height * src->height) + 10);
		int tempX = (tempLength + 1) / 2 - src->width / 2;
		int tempY = (tempLength + 1) / 2 - src->height / 2;
		int flag = -1;

		dst = cvCreateImage(cvSize(width, height), src->depth, src->nChannels);
		cvZero(dst);
		IplImage* temp = cvCreateImage(cvSize(tempLength, tempLength), src->depth, src->nChannels);

		cvZero(temp);

		cvSetImageROI(temp, cvRect(tempX, tempY, src->width, src->height));
		cvCopy(src, temp, NULL);
		cvResetImageROI(temp);

		if (clockwise)
			flag = 1;

		float m[6];
		int w = temp->width;
		int h = temp->height;
		m[0] = (float)cos(flag * angle * CV_PI / 180.);
		m[1] = (float)sin(flag * angle * CV_PI / 180.);
		m[3] = -m[1];
		m[4] = m[0];
		// 将旋转中心移至图像中间  
		m[2] = w * 0.5f;
		m[5] = h * 0.5f;

		CvMat M = cvMat(2, 3, CV_32F, m);
		cvGetQuadrangleSubPix(temp, dst, &M);
		cvReleaseImage(&temp);
	}
	catch (cv::Exception e)
	{
	}
	
	return dst;
}