opencv显示一块内存，单通道和三通道cross

void TestShowGrayImage(uint8_t* data,  int32_t width, int32_t height, int32_t stride,
                                            const String fileName, const String winName)
{
     Mat img(height, width, CV_8UC1);
 
     uint8_t * imgData = img.data;
     uint8_t * srcData = data;
     int32_t idx = 0;
     
     for (int32_t row = 0; row < img.rows; row++)
     {
         for (int32_t col = 0; col < img.cols; col++)
         {
             imgData[idx] = srcData[col];
             idx ++;
         }
         srcData += stride;
     }
 
     imwrite(fileName, img);
     imshow(winName, img);
     waitKey(0);
}