优化自VM图像类型转换专题（C#篇），易读且好用。

社区的代码展示没有高亮，加上图片便于阅读。

注意如果是 vm 4.3 版本，ImageData 的高度属性的名字是 Heigth 😅

附上代码文字便于黏贴。

    public ImageData MatToImageData(Mat mat)
    {
        ImageData img = new ImageData();
        byte[] buffer = new Byte[mat.Width * mat.Height * mat.Channels()];
        Marshal.Copy(mat.Ptr(0), buffer, 0, buffer.Length);        
        switch (mat.Channels())
        {
            case 1:
                img.Buffer = buffer;
                img.Width = mat.Width;
                img.Height = mat.Height;
                img.PixelFormat = ImagePixelFormate.MONO8;
                break;
            case 3:
                for (int i = 0; i < buffer.Length - 2; i += 3)
                {
                    byte temp = buffer[i];
                    buffer[i] = buffer[i + 2];
                    buffer[i + 2] = temp;
                }
                img.Buffer = buffer;
                img.Width = mat.Width;
                img.Height = mat.Height;
                img.PixelFormat = ImagePixelFormate.RGB24;
                break;
            default:                
                throw new Exception(string.Format("Unsupported channels: {0}", mat.Channels()));
        }
        return img;
    }


    public Mat ImageDataToMat(ImageData img)
    {
        Mat mat = null;
        switch (img.PixelFormat)
        {
            case ImagePixelFormate.MONO8:
                mat = new Mat(img.Height, img.Width, MatType.CV_8UC1);
                Marshal.Copy(img.Buffer, 0, mat.Ptr(0), img.Buffer.Length);
                break;
            case ImagePixelFormate.RGB24:
                mat = new Mat(img.Height, img.Width, MatType.CV_8UC3);
                Marshal.Copy(img.Buffer, 0, mat.Ptr(0), img.Buffer.Length);
                Cv2.CvtColor(mat, mat, ColorConversionCodes.RGB2BGR);
                break;
            default:
                throw new Exception("Unsupported vm-script img format!");
        }
        return mat;
    }