源码：

void twirl(cv::Mat& src,cv::Mat& dst,double angle,double radius)
{dst.create(src.rows, src.cols, CV_8UC3);dst.setTo(0);int radius2=radius*radius;int cx = src.cols / 2;int cy = src.rows / 2;int distance,distance2 = 0;for (int h = 0; h < dst.rows; h ++) {for (int w = 0; w < dst.cols; w ++) {int nh,nw;int dx = w - cx;int dy = h - cy;distance2 = dx * dx + dy * dy;if (distance2 > radius2){nw = w;nh = h;}else{distance = sqrt(distance2);double a = atan2(dy, dx) + angle * (radius - distance) / radius;nw = cx + distance*cos(a);nh = cy + distance*sin(a);}if (nw < 0 || nw > dst.cols - 1)nw = w;if (nh < 0 || nh > dst.rows - 1)nh = h;dst.at<Vec3b>(h, w)[0] = src.at<Vec3b>(nh, nw)[0];dst.at<Vec3b>(h, w)[1] = src.at<Vec3b>(nh, nw)[1];dst.at<Vec3b>(h, w)[2] = src.at<Vec3b>(nh, nw)[2];}}
}

原图及效果：