原文

滑鼠繪製直線原始碼：

#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))
	{
		cvCopy(dst,src);
		sprintf(temp,"(%d,%d)",x,y);
		cur_pt = cvPoint(x,y);		
		cvPutText(src,temp, cur_pt, &font, cvScalar(0,0, 0, 255));
		cvLine(src, pre_pt, cur_pt, cvScalar(0,255,0,0), 1, CV_AA, 0 );
		cvShowImage( "src", src );
	}
	else if( event == CV_EVENT_LBUTTONUP )
	{
		sprintf(temp,"(%d,%d)",x,y);
		cur_pt = cvPoint(x,y);		
		cvPutText(src,temp, cur_pt, &font, cvScalar(0,0, 0, 255));
		cvCircle( src, cur_pt, 3,cvScalar(255,0,0,0) ,CV_FILLED, CV_AA, 0 );
		cvLine( src, pre_pt, cur_pt, cvScalar(0,255,0,0), 1, CV_AA, 0 );
		cvShowImage( "src", src );
		cvCopy(src,dst);
	}
}
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;
}