效果图
#include <opencv2/opencv.hpp> using namespace cv; #define WINDOW_NAME "程序窗口" Rect g_rectangle; bool g_DrawingBox; RNG g_rng(12345); //矩形绘制函数 void DrawRectangle(Mat& img, 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 } //鼠标回调函数 void on_MouseHandle(int event, int x, int y, int flags, void *param) { Mat &image = *(Mat*)param; switch (event) { case EVENT_MOUSEMOVE: { if (g_DrawingBox) { g_rectangle.width = x - g_rectangle.x; g_rectangle.height = y - g_rectangle.y; } }break; case EVENT_LBUTTONDOWN: { g_DrawingBox = true; g_rectangle = Rect(x, y, 0, 0); }break; case EVENT_LBUTTONUP: { g_DrawingBox = false; 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; } DrawRectangle(image, g_rectangle); }break; } } int main(int argc, char**argv) { //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); namedWindow(WINDOW_NAME); setMouseCallback(WINDOW_NAME, on_MouseHandle, (void*)&srcImage); //主程序循环 while (1) { srcImage.copyTo(tempImage);//复制原图像临时变量 if (g_DrawingBox)DrawRectangle(tempImage, g_rectangle);//绘制 imshow(WINDOW_NAME, tempImage); if (waitKey(10) == 27)break; } return 0; }