OpenCV--鼠标事件响应

最新推荐文章于 2024-07-17 14:31:30 发布

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最新推荐文章于 2024-07-17 14:31:30 发布

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本文介绍了一个使用OpenCV库的示例程序，演示如何通过计算机鼠标在屏幕上绘制矩形框。该示例来源于《Learning OpenCV》一书第114至117页的内容。

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/**********************************************************
     This demo tries to demostrate the way how mouse event
   is responded in OpenCV. 
     It presents a way to draw a box on the screen through 
   a computer mouse. 
     A reference to this code is the demo in the wonderful
   book <learning OpenCV> on page 114 to page 117.
***********************************************************/


#include<cv.h>
#include<highgui.h>

#include<iostream>
using namespace std;


// callback function
void cvMouseCallback(int mouseEvent,int x,int y,int flags,void* param);

struct drawbox
{
	CvPoint point1;
	CvPoint point2;
	IplImage* image;
	IplImage* temp;
	bool isDraw;
};

int main(int argc,char* argv[])
{
	// declare and initialize a struct drawbox variable
	drawbox box;
	box.point1 = cvPoint(0,0);
	box.point2 = cvPoint(0,0);
	box.image = cvCreateImage(cvSize(640,480),IPL_DEPTH_8U,3);
	cvZero(box.image);
	box.temp = cvCloneImage(box.image);
	box.isDraw = false;

	// register a mouse callback function
	cvNamedWindow("exam",CV_WINDOW_AUTOSIZE);
	cvSetMouseCallback("exam",cvMouseCallback,&box);

	while(1)
	{
		cvCopy(box.image,box.temp);
		if(box.isDraw)  
		{
			cvRectangle(box.temp,box.point1,box.point2,CV_RGB(255,255,255));
		}
		cvShowImage("exam",box.temp);
		if(cvWaitKey(20) == 27)  break;
	}

	cvReleaseImage(&box.image);
	cvReleaseImage(&box.temp);
	cvDestroyWindow("exam");
	return 0;
}

void cvMouseCallback(int mouseEvent,int x,int y,int flags,void* param)
{
	drawbox* box = (drawbox*)param;
	switch(mouseEvent)
	{
	case CV_EVENT_LBUTTONDOWN:
		box->point1 = cvPoint(x,y);
		box->point2 = cvPoint(x,y);
		box->isDraw = true;
		break;
	case CV_EVENT_MOUSEMOVE:
		box->point2 = cvPoint(x,y);
		break;
	case CV_EVENT_LBUTTONUP:
		box->point2 = cvPoint(x,y);
		cvRectangle(box->image,box->point1,box->point2,CV_RGB(0,255,0));
		box->isDraw = false;
		break;
	}
	return;
}

http://blog.youkuaiyun.com/chenli2010/article/details/6896194