1.******************************

C#调用vc++ dll 传递参数的问题（Bitmap 转换为 opencv mat ），保存后图片不一样。

vc++ 代码

bool Recognize(Point_2F *arr,uchar* b)
{

Mat src=cv::Mat(415,770,CV_8UC3,b);

/*for (int i=0;i<src.rows;i++) 
{
memcpy(src.ptr(i),b+i*src.cols,src.cols);
}*/
cv::imwrite("D:\\my_2_testfiles\\111_before.png",src);

// 保存的照片和原来的照片不一样而且大小也不一样？

}

C#代码

 [DllImport("rectanglepoints.dll", EntryPoint = "Recognize", CallingConvention = CallingConvention.Cdecl)]
        static extern byte Recognize(IntPtr arr, IntPtr b);

{ 
 // Create a new bitmap.
            Bitmap bmp = new Bitmap("D:\\my_2_testfiles\\111.png");

            // Lock the bitmap's bits.  
            Rectangle rect = new Rectangle(0, 0, bmp.Width, bmp.Height);
            System.Drawing.Imaging.BitmapData bmpData =
                bmp.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite,
                bmp.PixelFormat);
            // Get the address of the first line.
            IntPtr ptrImg = bmpData.Scan0;
bool ret;
    ret = Convert.ToBoolean(Recognize(IntPtr.Zero, ptrImg));   

 // Unlock the bits.
            bmp.UnlockBits(bmpData);

            Console.Read();

        } 

照片附加

原图：

 

调用vc++ dll后保存的图片

2.******************************************************************

C#Bitmap和C++ opencv Mat相互转换  C#调用C++编译成的dll，这个dll中包含Opencv个的Mat到c#的Bitmap转换，具体代码如下：  C++部分：  首先创建win32应用程序，选择类库模板    DLL_APIuchar * _stdcall run1(char* filename, int&width, int&height, int&step) {   IplImage* uu = cvLoadImage(filename);   IplImage * dst1 = cvCreateImage(cvSize(uu->width, uu->height), 8, 1); cvCvtColor(uu, dst1, CV_RGB2GRAY); Matss = cvarrToMat(uu);   uchar * data = new uchar[uu->width*uu->height * 3]; data = ss.data;   width = ss.size().width; height = ss.size().height; step = ss.step;  return data; }  C#中调用这个dll  [DllImport(@"E:\Files\BarcodeProject\Code\testCode\OpenCvAssemblies\Debug\OpenCvAssemblies.dll" )]  publicstaticexternIntPtr run1(string a, outint width, outint height, outint step);  至此完成C++ Mat到Bitmap的转换  下面是Bitmap 到 Mat的转换 C# 部分  publicstaticBitmapInfoGetImagePixel(Bitmap Source) { byte[] result; int step;  intiWidth = Source.Width; intiHeight = Source.Height;  Rectanglerect = newRectangle(0, 0, iWidth, iHeight);  System.Drawing.Imaging.BitmapDatabmpData = Source.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite, Source.PixelFormat); IntPtriPtr = bmpData.Scan0;  intiBytes = iWidth * iHeight * 3; //根据通道数进行设置 byte[] PixelValues = newbyte[iBytes];    //int time = Environment.TickCount;  System.Runtime.InteropServices.Marshal .Copy(iPtr, PixelValues, 0, iBytes); //time = Environment.TickCount - time; //Console.WriteLine(time.ToString() + "ms"); Source.UnlockBits(bmpData); step = bmpData.Stride; result = PixelValues; // return result; // step = 0;  BitmapInfo bi = newBitmapInfo{ Result=result, Step=step }; return bi; } }  ///<summary> /// Bitmap信息类 ///</summary>  publicclassBitmapInfo {  publicbyte[] Result { get;  set; } publicint Step { get; set; }  }  Step 是扫描的步长，这个很重要，如果这个步长不是原来的值，就会造成图像偏移，从而造成失真。    C++部分  DLL_APIvoid_stdcallshow(uchar* data,intwidth,intheight,intstep) { Matimage(height,width, CV_8UC3,data,step); //image.data = data; imshow("Image",image);    //Mat(int rows, int cols, int type, void* data, size_t step = AUTO_STEP); }  C# 中调用方式  BitmapInfo bi = GetImagePixel(bitmap);  show(bi.Result,bitmap.Width,bitmap.Height,bi.Step);  至此完成他们的相互转换