在OpenCV中利用滑鼠繪制矩形和截取圖像的矩形區域

程式之一，在OpenCV中利用滑鼠繪制矩形

#include <cv.h>  

#include <highgui.h>  

#include <stdio.h>  

#pragma comment( lib, "cv.lib" )  

#pragma comment( lib, "cxcore.lib" )  

#pragma comment( lib, "highgui.lib" )  

IplImage* src = 0;   

IplImage* dst = 0;   

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(dst,src);  

        sprintf(temp,"(%d,%d)",x,y);  

        pre_pt = cvPoint(x,y);  

        cvPutText(src,temp, pre_pt, &font, cvScalar(0,0, 0, 255));  

        cvCircle( src, pre_pt, 3,cvScalar(255,0,0,0) ,CV_FILLED, CV_AA, 0 );  

        cvShowImage( "src", src );  

        cvCopy(src,dst);  

    }  

    else if( event == CV_EVENT_MOUSEMOVE && !(flags & CV_EVENT_FLAG_LBUTTON))  

        cur_pt = cvPoint(x,y);        

        cvPutText(src,temp, cur_pt, &font, cvScalar(0,0, 0, 255));  

    else if( event == CV_EVENT_MOUSEMOVE && (flags & CV_EVENT_FLAG_LBUTTON))  

        cvRectangle(src, pre_pt, cur_pt, cvScalar(0,255,0,0), 1, 8, 0 );  

    else if( event == CV_EVENT_LBUTTONUP )  

        cvCircle( src, cur_pt, 3,cvScalar(255,0,0,0) ,CV_FILLED, CV_AA, 0 );  

        cvRectangle( src, pre_pt, cur_pt, cvScalar(0,255,0,0), 1, 8, 0 );  

}  

int main()  

    src=cvLoadImage("lena.jpg",1);  

    dst=cvCloneImage(src);  

    cvNamedWindow("src",1);  

    cvSetMouseCallback( "src", on_mouse, 0 );  

    cvShowImage("src",src);  

    cvWaitKey(0);   

    cvDestroyAllWindows();  

    cvReleaseImage(&src);  

    cvReleaseImage(&dst);  

    return 0;  

效果圖如下

程式之二，在OpenCV中利用滑鼠繪制矩形并截取該矩形區域的圖像

IplImage* org = 0;  

IplImage* img = 0;   

IplImage* tmp = 0;   

        cvCopy(org,img);  

        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);  

        cvCopy(tmp,img);  

        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 );  

        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 );  

        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);  

        cvSaveImage("dst.jpg",dst);  

    org=cvLoadImage("lena.jpg",1);  

    img=cvCloneImage(org);  

    tmp=cvCloneImage(org);  

    cvNamedWindow("img",1);  

    cvSetMouseCallback( "img", on_mouse, 0 );  

    cvShowImage("img",img);  

    cvReleaseImage(&org);  

    cvReleaseImage(&img);  

    cvReleaseImage(&tmp);