采用最近邻插值算法的实现代码为：

cv::Mat matSrc = cv::imread("lena.jpg", 2 | 4);	if (matSrc.empty()) return;	const double degree = 45;	double angle = degree * CV_PI / 180.;	double alpha = cos(angle);	double beta = sin(angle);	int iWidth = matSrc.cols;	int iHeight = matSrc.rows;	int iNewWidth = cvRound(iWidth * fabs(alpha) + iHeight * fabs(beta));	int iNewHeight = cvRound(iHeight * fabs(alpha) + iWidth * fabs(beta));	double m[6];	m[0] = alpha;	m[1] = beta;	m[2] = (1 - alpha) * iWidth / 2. - beta * iHeight / 2.;	m[3] = -m[1];	m[4] = m[0];	m[5] = beta * iWidth / 2. + (1 - alpha) * iHeight / 2.;	cv::Mat M = cv::Mat(2, 3, CV_64F, m);	cv::Mat matDst1 = cv::Mat(cv::Size(iNewWidth, iNewHeight), matSrc.type(), cv::Scalar::all(0));	double D = m[0]*m[4] - m[1]*m[3];	D = D != 0 ? 1./D : 0;	double A11 = m[4]*D, A22 = m[0]*D;	m[0] = A11; m[1] *= -D;	m[3] *= -D; m[4] = A22;	double b1 = -m[0]*m[2] - m[1]*m[5];	double b2 = -m[3]*m[2] - m[4]*m[5];	m[2] = b1; m[5] = b2;	int round_delta = 512;//nearest	for (int y=0; y
     
      (m[0] * x * 1024);			int bdelta = cv::saturate_cast
      
       (m[3] * x * 1024);			int X0 = cv::saturate_cast
       
        ((m[1] * y + m[2]) * 1024) + round_delta;			int Y0 = cv::saturate_cast
        
         ((m[4] * y + m[5]) * 1024) + round_delta;			int X = (X0 + adelta) >> 10;			int Y = (Y0 + bdelta) >> 10;			if ((unsigned)X < iWidth && (unsigned)Y < iHeight)			{				matDst1.at
         
          (y, x) = matSrc.at
          
           (Y, X); } } } cv::imwrite("rotate_nearest_1.jpg", matDst1); M = cv::getRotationMatrix2D(cv::Point2f(iWidth / 2., iHeight / 2.), degree, 1); cv::Mat matDst2; cv::warpAffine(matSrc, matDst2, M, cv::Size(iNewWidth, iNewHeight), 0, 0, 0); cv::imwrite("rotate_nearest_2.jpg", matDst2);
          
         
        
       
      
     

采用双线性插值算法的实现代码为：

cv::Mat matSrc = cv::imread("lena.jpg", 2 | 4);	if (matSrc.empty()) return;	const double degree = 45;	double angle = degree * CV_PI / 180.;	double alpha = cos(angle);	double beta = sin(angle);	int iWidth = matSrc.cols;	int iHeight = matSrc.rows;	int iNewWidth = cvRound(iWidth * fabs(alpha) + iHeight * fabs(beta));	int iNewHeight = cvRound(iHeight * fabs(alpha) + iWidth * fabs(beta));	double m[6];	m[0] = alpha;	m[1] = beta;	m[2] = (1 - alpha) * iWidth / 2. - beta * iHeight / 2.;	m[3] = -m[1];	m[4] = m[0];	m[5] = beta * iWidth / 2. + (1 - alpha) * iHeight / 2.;	cv::Mat M = cv::Mat(2, 3, CV_64F, m);	cv::Mat matDst1 = cv::Mat(cv::Size(iNewWidth, iNewHeight), matSrc.type(), cv::Scalar::all(0));	double D = m[0]*m[4] - m[1]*m[3];	D = D != 0 ? 1./D : 0;	double A11 = m[4]*D, A22 = m[0]*D;	m[0] = A11; m[1] *= -D;	m[3] *= -D; m[4] = A22;	double b1 = -m[0]*m[2] - m[1]*m[5];	double b2 = -m[3]*m[2] - m[4]*m[5];	m[2] = b1; m[5] = b2;	for (int y=0; y
     
      = iHeight) continue;			short cbufy[2];			cbufy[0] = cv::saturate_cast
      
       ((1.f - fy) * 2048);			cbufy[1] = 2048 - cbufy[0];			int sx = cvFloor(fx);			fx -= sx;			//if (sx < 0) {			//	fx = 0, sx = 0;			//}			//if (sx >= iWidth - 1) {			//	fx = 0, sx = iWidth - 2;			//}			if (sx < 0 || sx >= iWidth) continue;			short cbufx[2];			cbufx[0] = cv::saturate_cast
       
        ((1.f - fx) * 2048);			cbufx[1] = 2048 - cbufx[0];			for (int k=0; k
        
         (y, x)[k] = (matSrc.at
         
          (sy, sx)[k] * cbufx[0] * cbufy[0] + matSrc.at
          
           (sy+1, sx)[k] * cbufx[0] * cbufy[1] + matSrc.at
           
            (sy, sx+1)[k] * cbufx[1] * cbufy[0] + matSrc.at
            
             (sy+1, sx+1)[k] * cbufx[1] * cbufy[1]) >> 22; } } } } cv::imwrite("rotate_bilinear_1.jpg", matDst1); M = cv::getRotationMatrix2D(cv::Point2f(iWidth / 2., iHeight / 2.), degree, 1); cv::Mat matDst2; cv::warpAffine(matSrc, matDst2, M, cv::Size(iNewWidth, iNewHeight), 1, 0, 0); cv::imwrite("rotate_bilinear_2.jpg", matDst2);