使用变换矩阵旋转点

Question

如何使用变换矩阵旋转点？

 var point = new PointF(100, 150);
 var center = new PointF(100, 100);
 var angle = 45;

 var rotateMat = Cv2.GetRotationMatrix2D(new Point2f(center.Y, center.X), angle, 1);
 ???

Answer 1

var point = new PointF(100, 150);
var center = new PointF(100, 100);
var angle = 45;

var rotateMat = Cv2.GetRotationMatrix2D(new Point2f(center.Y, center.X), angle, 1);
var resultPoint = (rotateMat * point.ToMat()).ToMat().ToPointF();

static class Hlp
{
  public static PointF ToPointF(this Mat mat)
  {
    return new PointF((float)mat.Get<double>(1, 0), (float)mat.Get<double>(0, 0));
  }
  public static Mat ToMat(this PointF point)
  {
    return new Mat(3, 1, MatType.CV_64FC1, new double[] { point.Y, point.X, 1 });
  }
}