[MFC] 绘制图像ROI区域(OpenCv库)

Mat org,dst,img,tmp;  
void CQRCodeDemoDlg::OnBnClickedSetRoi()   //设置ROI区域（按钮事件）
{ 
    imagedst.copyTo(img);  //图片接口
    imagedst.copyTo(tmp);  //临时变量
    namedWindow("view");//定义一个img窗口  
    setMouseCallback("view",on_mouse,0);//调用回调函数  
    imshow("view",img);  
    cv::waitKey(0); 
}

void on_mouse(int event,int x,int y,int flags,void *ustc)//event鼠标事件代号，x,y鼠标服务器托管网坐标，flags拖拽和键盘操作的代号  
{  
    static Point pre_pt = (-1,-1);//初始坐标  
    static Point cur_pt = (-1,-1);//实时坐标  
    //char temp[16];  
    if (event == CV_EVENT_LBUTTONDOWN)//左键按下，读取初始坐标，并在图像上该点处划圆  
    {  
        imagedst.copyTo(img);//将原始图片复制到img中  
       // sprintf(temp,"(%d,%d)",x,y);  
        pre_pt = Point(x,y);  
       // putText(img,temp,pre_pt,FONT_HERSHEY_SIMPLEX,0.5,Scalar(0,0,0,255),1,8);//在窗口上显示坐标  
        circle(img,pre_pt,2,Scalar(255,0,0,0),CV_FILLED,CV_AA,0);//划圆  
        imshow("view",img);  
    }  
    else if (event == CV_EVENT_MOUSEMOVE && !(flags & CV_EVENT_FLAG_LBUTTON))//左键没有按下的情况下鼠标移动的处理函数  
    {  
        img.copyTo(tmp);//将img复制到临时图像tmp上，用于显示实时坐标  
       // sprintf(temp,"(%d,%d)",x,y);  
        cur_pt = Point(x,y);  
        //putText(tmp,temp,cur_pt,FONT_HERSHEY_SIMPLEX,0.5,Scalar(0,0,0,255));//只是实时显示鼠标移动的坐标  
        imshow("view",tmp);  
    }  
    else if (event == CV_EVENT_MOUSEMOVE && (flags & CV_EVENT_FLAG_LBUTTON))//左键按下时，鼠标移动，则在图像上划矩形  
    {  
        img.copyTo(tmp);  
       // sprintf(temp,"(%d,%d)",x,y);  
        cur_pt = Point(x,y);  
      //  putText(tmp,temp,cur_pt,FONT_HERSHEY_SIMPLEX,0.5,Scalar(0,0,0,255));  
        rectangle(tmp,pre_pt,cur_pt,Scalar(0,0,255,0),1,8,0);//在临时图像上实时显示鼠标拖动时形成的矩形  
        imshow("view",tmp);  
    }  
    else if (event == CV_EVENT_LBUTTONUP)//左键松开，将在图像上划矩形  
    {  
        imagedst.copyTo(img);  
       // sprintf(temp,"(%d,%d)",x,y);  
        cur_pt = Point(x,y);  
       // putText(img,temp,cur_pt,FONT_HERSHEY_SIMPLEX,0.5,Scalar(0,0,0,255));  
        circle(img,pre_pt,2,Scalar(255,0,0,0),CV_FILLED,CV_AA,0);  
        rectangle(img,pre_pt,cur_pt,Scalar(0,255,0,0),1,8,0);//根据初始点和结束点，将矩形画到img上  
        imshow("view",img);  
        img.copy服务器托管网To(tmp);  
        //截取矩形包围的图像，并保存到dst中  
        int width = abs(pre_pt.x - cur_pt.x);  
        int height = abs(pre_pt.y - cur_pt.y);  
        if (width == 0 || height == 0)  
        {  
            printf("width == 0 || height == 0");  
            return;  
        }  
        //对原图进行裁剪
        dst =imagedst(Rect(min(cur_pt.x,pre_pt.x),min(cur_pt.y,pre_pt.y),width,height));  
       // namedWindow("dst");  
      //  imshow("dst",dst);     //显示的ROI区域图片
        waitKey(0);  
    }  
}