参考： https://blog.csdn.net/cl2227619761/article/details/79897804 https://blog.csdn.net/weixin_30641465/article/details/98899952
以下代码可以实现在保持图片尺寸的情况下，旋转图片（不过好像还有角落那里有点黑边，有能力的同学去看看前面提到的博客看源码，看能不能解决）
//crop 是否裁剪 void cropRotateImage(const cv::Mat &source, cv::Mat &dst, double angle, bool crop ) { angle = fmod(angle, 360.0);//double类型取余数 cv::Point2f center = cv::Point2f(source.rows / 2, source.rows / 2); double scale = 1; // 缩放尺度 cv::Mat rotateMat; rotateMat = cv::getRotationMatrix2D(center, angle, scale); Mat temp; cv::warpAffine(source, temp, rotateMat, source.size()); if(crop == false) { dst = temp.clone(); } else { int h = source.rows; int w = source.cols; double angle_crop = fmod(angle, 180.0); if(angle > 90) { angle_crop = 180 - angle_crop; } double theta = angle_crop * CV_PI / 180.0; double hw_ratio = float(h) / float(w); double tan_theta = tan(theta); double numerator = cos(theta) + sin(theta) * tan(theta); double r = h > w ? hw_ratio : (1.0 / hw_ratio); double denominator = r * tan_theta + 1.0; double crop_mult = numerator / denominator; int w_crop = int(crop_mult * w); int h_crop = int(crop_mult * h); int x0 = int((w - w_crop) / 2); int y0 = int((h - h_crop) / 2); cv::Rect2i roi(x0, y0, w_crop, h_crop); cv::resize(temp(roi), dst, source.size()); } }调用就这样子调用
Mat img = imread("1.bmp"); Mat rotatedMat; Mat cropRotatedMat; cropRotateImage(img, rotatedMat, 45, false); cropRotateImage(img, cropRotatedMat, 45, true); imshow("img", img); imshow("rImg", rotatedMat); imshow("crImg", cropRotatedMat);