Dégradé de couleur

#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <iostream>

using namespace std;
using namespace cv;

int i, ;

main( int argc, char* argv[])
{
 Mat imagesrc = Mat::zeros(512, 512, CV_8UC3);  
 MatIterator_<Vec3b> it,end ;

 for( it = imagesrc.begin<Vec3b>(), end = imagesrc.end<Vec3b>(); it != end; ++it)
 {
                {




                    (*it)[0] = 0;   
                    (*it)[1] = 0;   
                    (*it)[2] = i;


           i = i+1; 
                }
 if (i==512) i = 0;      
 }
cv::imwrite("c:\image3.jpg", imagesrc);   


 namedWindow( "Display window", CV_WINDOW_AUTOSIZE );
 imshow( "Display window", imagesrc );

 waitKey(0);
 return 0;                                                         

}