openCV实现鼠标响应裁剪图像

- 日理万妓 2022-06-12 05:10 164阅读 0赞

给定一幅图像，将其中的某一部分兴趣区域裁剪出来，这在PS中很好实现，但是使用openCV如何实现呢？因此本文主要介绍openCV使用鼠标响应来裁剪图像：  
一、代码部分：

#include "stdafx.h"
    #include "cv.h" 
    #include <highgui.h> 
    #include <stdio.h> 
    
    IplImage* org = 0;  
    IplImage* img = 0;   
    IplImage* tmp = 0;   
    IplImage* dst = 0;  
    //The mouse cuts the image accordingly
    void on_mouse( int event, int x, int y, int flags, void* ustc)  
    {  
        static CvPoint pre_pt = {-1,-1};  
        static CvPoint cur_pt = {-1,-1};  
        CvFont font;  
        cvInitFont(&font, CV_FONT_HERSHEY_SIMPLEX, 0.5, 0.5, 0, 1, CV_AA);  
        char temp[16];  
    
        if(event == CV_EVENT_LBUTTONDOWN)  
        {  
            cvCopy(org,img);  
            sprintf(temp,"(%d,%d)",x,y);  
            pre_pt = cvPoint(x,y);  
            cvPutText(img,temp, pre_pt, &font, cvScalar(0,0, 0, 255));  
            cvCircle( img, pre_pt, 3,cvScalar(255,0,0,0) ,CV_FILLED, CV_AA, 0 );  
            cvShowImage( "img", img );  
            cvCopy(img,tmp);  
        }  
        else if( event == CV_EVENT_MOUSEMOVE && !(flags & CV_EVENT_FLAG_LBUTTON))  
        {  
            cvCopy(tmp,img);  
            sprintf(temp,"(%d,%d)",x,y);  
            cur_pt = cvPoint(x,y);        
            cvPutText(img,temp, cur_pt, &font, cvScalar(0,0, 0, 255));  
            cvShowImage( "img", img );  
        }  
        else if( event == CV_EVENT_MOUSEMOVE && (flags & CV_EVENT_FLAG_LBUTTON))  
        {  
            cvCopy(tmp,img);  
            sprintf(temp,"(%d,%d)",x,y);  
            cur_pt = cvPoint(x,y);        
            cvPutText(img,temp, cur_pt, &font, cvScalar(0,0,0,255));  
            cvRectangle(img, pre_pt, cur_pt, cvScalar(0,255,0,0), 1, 8, 0 );  
            cvShowImage( "img", img );  
        }  
        else if(event == CV_EVENT_LBUTTONUP)  
        {  
            cvCopy(tmp,img);  
            sprintf(temp,"(%d,%d)",x,y);  
            cur_pt = cvPoint(x,y);        
            cvPutText(img,temp, cur_pt, &font, cvScalar(0,0, 0, 255));  
            cvCircle( img, cur_pt, 3,cvScalar(255,0,0,0) ,CV_FILLED, CV_AA, 0 );  
            cvRectangle( img, pre_pt, cur_pt, cvScalar(0,255,0,0), 1, 8, 0 );  
            cvShowImage( "img", img );  
            cvCopy(img,tmp);  
            int width=abs(pre_pt.x-cur_pt.x);  
            int height=abs(pre_pt.y-cur_pt.y);  
            if(width==0 || height==0)  
            {  
                cvDestroyWindow("dst");  
                return;  
            }  
            dst=cvCreateImage(cvSize(width,height),org->depth,org->nChannels);  
            CvRect rect;  
            if(pre_pt.x<cur_pt.x && pre_pt.y<cur_pt.y)  
            {  
                rect=cvRect(pre_pt.x,pre_pt.y,width,height);  
            }  
            else if(pre_pt.x>cur_pt.x && pre_pt.y<cur_pt.y)  
            {  
                rect=cvRect(cur_pt.x,pre_pt.y,width,height);  
            }  
            else if(pre_pt.x>cur_pt.x && pre_pt.y>cur_pt.y)  
            {  
                rect=cvRect(cur_pt.x,cur_pt.y,width,height);  
            }  
            else if(pre_pt.x<cur_pt.x && pre_pt.y>cur_pt.y)  
            {  
                rect=cvRect(pre_pt.x,cur_pt.y,width,height);  
            }  
            cvSetImageROI(org,rect);  
            cvCopy(org,dst);  
            cvResetImageROI(org);  
            cvDestroyWindow("dst");  
            cvNamedWindow("dst",1);  
            cvShowImage("dst",dst);  
            cvWaitKey(0);
            cvSaveImage("..\\post_img\\71253.jpg",dst);  
        }  
    } 
    
    int _tmain(int argc, _TCHAR* argv[])
    {
        org=cvLoadImage("..\\image_norm\\71253.jpg",1);  
        img=cvCloneImage(org);  
        tmp=cvCloneImage(org);  
        cvNamedWindow("img",1);  
        cvSetMouseCallback( "img", on_mouse, 0);  
    
        cvShowImage("img",img);  
        cvWaitKey(0);   
        cvDestroyAllWindows();  
        cvReleaseImage(&org);  
        cvReleaseImage(&img);  
        cvReleaseImage(&tmp);  
        cvReleaseImage(&dst);  
        return 0;
    }

二、程序运行效果图：  
![这里写图片描述][SouthEast]  
将鼠标放在原图上的某一点，会显示相应点的位置坐标。至此，openCV使用鼠标响应实现图像裁剪已经实现。

[SouthEast]: /images/20220612/929dce49e7d2436fa81069a7f963732e.png