opencv IplImage矩阵元素赋值

void DrawPoint(IplImage* img,CvPoint point,CvScalar color)
{
	int step = img->widthStep;
	unsigned char* ImgData;
	ImgData = (unsigned char *)img->imageData;
	for(int i=0;i<3;i++)
	{
		ImgData[point.y*step+point.x*3+i]=MyValue;
	}
}