[OpenCvSHarp]小练习，计算仿射变换后的坐标_如何在仿射坐标系下找点的坐标-优快云博客

本文介绍了一种使用Cv2库实现图像旋转的方法，并通过示例代码详细展示了如何定义旋转中心、旋转角度及放大系数，同时对变换后的坐标进行了计算与标记。

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先用红点标出旋转中心的位置，用绿点标出转换前的位置

变换之后，红圈圈出新的坐标

改变旋转中心，角度，放大系数：

结果：

源码：

public void Run()
        {

            Mat mat = new Mat(800, 800, MatType.CV_8UC3);

      
            //网络线
            for (int i = 0; i <= 10; i++)
            {

                Cv2.Line(mat, new Point(i * 100 + 50, 0), new Point(i * 100 + 50, 800), new Scalar(60,60,60));
                Cv2.Line(mat, new Point(0, i * 100 + 50), new Point(800, i * 100 + 50), new Scalar(60, 60, 60));
                Cv2.Line(mat, new Point(i * 100, 0), new Point(i * 100, 800), Scalar.Gray );
                Cv2.Line(mat, new Point(0, i * 100), new Point(800, i * 100), Scalar.Gray );

            }

            //旋转中心
            Point center = new Point(300, 400);
            Cv2.Circle(mat, center, 5, Scalar.Red, -1);
            Cv2.ArrowedLine(mat, center, center+new Point(100,0), Scalar.Green);
            Cv2.ArrowedLine(mat, center, center + new Point(0, 100), Scalar.Red);
            //测试点
            Point p = new Point(250, 450);
            Cv2.Circle(mat, p, 5, Scalar.Lime, -1);
 
            Cv2.ImShow("T", mat);
            Mat mat1 = MatRotate(mat, center, -65, p);
            Cv2.ImShow("T1", mat1);

            Cv2.WaitKey();
}

 private Mat MatRotate(Mat src, Point center, float angle, Point point)
        {


            Mat dst = new Mat();
            Mat rot = Cv2.GetRotationMatrix2D(center, angle, 1.5);
            Console.WriteLine(Cv2.Format(rot, FormatType.Python));

            Cv2.WarpAffine(src, dst, rot, src.Size());
 

            var x = point.X * rot.At<double>(0, 0) + point.Y * rot.At<double>(0, 1) + rot.At<double>(0, 2);
            var y = point.X * rot.At<double>(1, 0) + point.Y * rot.At<double>(1, 1) + rot.At<double>(1, 2);
            x = Math.Round(x, 0);
            y = Math.Round(y, 0);
            Point p = new Point(x, y);
 
            Cv2.Circle(dst, p, 10, Scalar.Red, 1);

            return dst;
        }