opencv学习笔记——鼠标操作

#include <opencv2/opencv.hpp>using namespace cv;#define WINDOW_NAME     "【程序窗口】"            //为窗口标题定义的宏/* 全局函数的声明 */void on_MouseHandle(int event, int x, int y, int flags, void *param);void DrawRectangle(cv::Mat& img, cv::Rect box);void ShowHelpText();/* 全局变量的声明 */Rect g_rectangle;bool g_bDrawingBox = false;                     //是否进行绘制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，当进行绘制的标识符为真时，进行绘制    while (1) {        srcImage.copyTo(tempImage);        if (g_bDrawingBox)            DrawRectangle(tempImage, g_rectangle);      //当进行绘制的标识符为真，则进行绘制        imshow(WINDOW_NAME, tempImage);        if (waitKey(10) == 27)            break;                                      //按下ESC键，程序退出    }    return 0;}/* 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 *param){    Mat image = *(cv::Mat*)param;    switch (event) {        //鼠标移动消息        case EVENT_MOUSEMOVE:            if (g_bDrawingBox) {                        //如果是否进行绘制的标识符为真，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            break;        //左键抬起消息        case EVENT_LBUTTONUP:            g_bDrawingBox = false;                      //置标识符为false            //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;            }            if (g_rectangle.height < 0) {                g_rectangle.y += g_rectangle.height;                g_rectangle.height *= -1;            }            //调用函数进行绘制            DrawRectangle(image, g_rectangle);            break;    }}/* 自定义矩形绘制函数 */void DrawRectangle(cv::Mat& img, cv::Rect box){    //随机函数    rectangle(img, box.tl(), box.br(), Scalar(g_rng.uniform(0, 255), g_rng.uniform(0, 255), g_rng.uniform(0, 255)));}

setMouseCallback函数

void setMouseCallback(const string& winname, MouseCallback onMouse, void* userdata = 0)

参数 说明 winname const string&类型，窗口的名字 onMouse MouseCallback类型，指定窗口里每次鼠标事件发生时调用的函数指针

鼠标回调函数

void Foo(int event, int x, int y, int flags, void* param)

  event是EVENT_+变量之一，x和y是鼠标指针在图像坐标系中的坐标，flags是EVENT_FLAG的组合，param是用户传递到setMouseCallback函数调用的参数。

Rect函数

Rect(x,y,width,height)

  x, y 为左上角坐标, width, height 则为长和宽。

//利用对角线两点来画矩形：void rectangle(Mat& img, Point pt1,Point pt2,const Scalar& color, int thickness=1, int lineType=8, int shift=0)//传入矩形参数来画矩形：void rectangle(Mat& img, Rect rec, const Scalar& color, int thickness=1, int lineType=8, int shift=0 )