3.5 鼠标操作

/**
*Copyright (c) 2018 Young Fan.All Right Reserved.
*Filename: 5 鼠标操作
*Author: Young Fan
*Date: 2018.4.6
*OpenCV version: 3.4.1
*IDE: Visual Studio 2017
*Description: 鼠标操作
*/

#include<opencv2/opencv.hpp>
using namespace cv;

#define WINDOW_NAME "程序窗口"

//---------------------【全局函数声明部分】-----------
void on_MouseHandle(int event,int x,int y,int flags,void* parma);
void DrawRectangle(cv::Mat &img,cv::Rect box); 

//----------------------【全局变量声明】---------------
Rect g_rectangle;
bool g_bDrawingBox = false;//是否进行绘制,标志符
RNG g_rng(12345);

int main(int argc,char** argv)
{
    //1.准备参数
    g_rectangle = Rect(-1,-1,0,0);
    Mat srcImage(600,800,CV_8UC3),tempImage;
    srcImage.copyTo(tempImage);
    g_rectangle = Rect(-1,-1,0,0);
    srcImage = Scalar::all(0);

    //2.设置鼠标操作回调函数
    namedWindow(WINDOW_NAME);
    setMouseCallback(WINDOW_NAME,on_MouseHandle,(void*) &srcImage);

    //3.程序主循环，当进行绘制的标识为真时，进行绘制
    while (1)
    {
        srcImage.copyTo(tempImage);//复制原图到临时变量
        if (g_bDrawingBox)
            DrawRectangle(tempImage, g_rectangle);//当标志符为真时，则进行绘制
        imshow(WINDOW_NAME, tempImage);
        if (waitKey(10) == 27)
            break;//按下Esc键，程序退出
    }

    return 0;
}

//---------------------------【on_MouseHandle()函数】----------------------
//描述：鼠标回调函数，根据不同的鼠标事件进行不同的操作
//-------------------------------------------------------------------------
void on_MouseHandle(int event, int x, int y, int flags, void* parma)
{
    Mat &image = *(cv::Mat*) parma;
    switch (event)
    {
        //鼠标移动消息
        case EVENT_MOUSEMOVE:
        {
            if (g_bDrawingBox) //如果绘制标志符为真，则记录下长和宽到RECT型变量中
            {
                g_rectangle.width = x - g_rectangle.x;
                g_rectangle.height = y - g_rectangle.y;
            }
        }
        break;

        //左键按下消息
        case EVENT_LBUTTONDOWN:
        {
            g_bDrawingBox = true;
            g_rectangle = Rect(x,y,0,0);//记录起始点
            printf("左键按下了\n");
        }
        break;

        //左键抬起消息
        case EVENT_LBUTTONUP:
        {
            g_bDrawingBox = false;//置标志符为false
            printf("左键抬起了\n");
            //对宽和高小于0的处理
            if (g_rectangle.width < 0)
            {
                g_rectangle.x += g_rectangle.width;
                g_rectangle.width *= -1;//a *= b,即a = a*b;
            }
            if (g_rectangle.height < 0)
            {
                g_rectangle.y += g_rectangle.height;
                g_rectangle.height *= -1;//a *= b,即a = a*b;
            }
            //调用函数进行绘制
            DrawRectangle(image,g_rectangle);
        }
        break;
    }
}

//-------------------------【DrawRectangle()函数】-----------------
//描述：自定义的矩形绘制函数
//-----------------------------------------------------------------
void DrawRectangle(cv::Mat &img, cv::Rect box)
{
    rectangle(img,box.tl(),box.br(),Scalar(g_rng.uniform(0,255),
        g_rng.uniform(0,255),g_rng.uniform(0,255)));//随机颜色
}

结果：