#include <cv.h>
#include <highgui.h>
#include <stdio.h>
 
IplImage* src = 0; 
IplImage* tmp = 0; 
IplImage* tmp1 = 0;
IplImage* org = 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);//初始化字體
 char temp[16];
 
 if( (event == CV_EVENT_LBUTTONDOWN)&&(flags) )//鼠標左鍵按下時
 { 
 sprintf(temp,"(%d,%d)",x,y);//格式化字符串
 pre_pt = cvPoint(x,y);//獲取當前點坐標值
 cvPutText(src,temp, pre_pt, &font, cvScalar(0,0, 0, 255));//在圖像是打印字符
 cvCircle( src, pre_pt, 2,cvScalar(255,0,0,0) ,CV_FILLED, CV_AA, 0 );//在圖像上畫圓
 cvShowImage( "src", src );
 //cvCopy(src,tmp);//這句有沒有，就是單目標和多目標的問題
 }
 else if( (event == CV_EVENT_MOUSEMOVE) && (flags & CV_EVENT_LBUTTONDOWN))
 {//鼠標移動并且鼠標左鍵按下
 sprintf(temp,"(%d,%d)",x,y);//格式化字符串
 cur_pt = cvPoint(x,y);//獲取當前點坐標值 
 cvPutText(src,temp, cur_pt, &font, cvScalar(0,0, 0, 255));//在圖像是打印字符
 cvRectangle(src, pre_pt, cur_pt, cvScalar(0,255,0,0), 2, 8, 0 );//在圖像上畫矩形
 cvShowImage( "src", src );
 cvCopy(tmp,src);//將img復制到臨時圖像tmp上，用于實時顯示
 }
 else if( event == CV_EVENT_LBUTTONUP )
 {//鼠標左鍵彈起
 sprintf(temp,"(%d,%d)",x,y);//字體格式化
 cur_pt = cvPoint(x,y);//獲取當前點坐標值 
 cvPutText(src,temp, cur_pt, &font, cvScalar(0,0, 0, 255));//在圖像是打印字符
 cvCircle( src, cur_pt, 2,cvScalar(255,0,0,0) ,CV_FILLED, CV_AA, 0 );//在圖像上畫圓
 cvRectangle( src, pre_pt, cur_pt, cvScalar(0,255,0,0), 2, 8, 0 );//在圖像上畫矩形
 cvShowImage( "src", src );
 
 /******************************************************************/
 int width=abs(pre_pt.x-cur_pt.x); //兩點橫坐標差 
    int height=abs(pre_pt.y-cur_pt.y); //兩點縱坐標差 
    if(width==0 || height==0) 
    { //兩者中有一個為零時銷毀窗口
      cvDestroyWindow("dst"); 
      return; 
    } 
    tmp1 = 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);//設置圖像的感興趣區(qū)域 
    cvCopy(org,tmp1); //將感興趣區(qū)域復制到tmp1 
    cvResetImageROI(org);//釋放圖像的感興趣區(qū)域 
    cvDestroyWindow("dst");//銷毀上次的顯示圖像 
    cvNamedWindow("dst",1);//新建窗口 
    cvShowImage("dst",tmp1); //顯示感興趣的圖像 
    cvSaveImage("dst.jpg",tmp1); //保存感興趣圖像 
/******************************************************************/
 }
}
int main()
{
 src=cvLoadImage("lena.jpg",1);//讀入圖像
 tmp=cvCloneImage(src);//復制圖像到臨時圖像上 
 org=cvCloneImage(src);//保存原始圖像 
 cvNamedWindow("src",1);//新建窗口
 cvSetMouseCallback( "src", on_mouse, 0 );//注冊鼠標響應回調(diào)函數(shù)
 
 cvShowImage("src",src);//顯示圖像
 cvWaitKey(0);//等待按鍵按下 
 cvDestroyAllWindows();//銷毀所有窗口
 cvReleaseImage(&src);//釋放圖像
 cvReleaseImage(&tmp);//釋放圖像
 return 0;
}