OpenCV GUI基本操作，回调函数，进度条，裁剪图像等

工具条进度条：

// ConvertColor.cpp : 定义控制台应用程序的入口点。 //  #include "stdafx.h"  #include <iostream> #include <opencv2/highgui/highgui.hpp> #include <opencv2/imgproc/imgproc.hpp>  #pragma comment(lib,"opencv_core2410d.lib")             #pragma comment(lib,"opencv_highgui2410d.lib")             #pragma comment(lib,"opencv_imgproc2410d.lib")    using namespace std; using namespace cv; // Global variables const int slider_max = 100; int slider; Mat img; // Callback function for trackbar event void on_trackbar(int pos, void *) {  Mat img_converted;  if(pos > 0) cvtColor(img, img_converted, CV_RGB2GRAY);  else img_converted = img;  imshow("Trackbar app", img_converted); } int main() {  img = imread("swan.jpg");  namedWindow("Trackbar app");  imshow("Trackbar app", img);  slider = 0;  createTrackbar("RGB <-> Grayscale", "Trackbar app", &slider, slider_max, on_trackbar);  while(char(waitKey(1)) != 'q') {}  return 0; }

效果：

图像裁切代码：

// ConvertColor.cpp : 定义控制台应用程序的入口点。 //  #include "stdafx.h"  #include <iostream> #include <opencv2/highgui/highgui.hpp> #include <opencv2/imgproc/imgproc.hpp>  #pragma comment(lib,"opencv_core2410d.lib")             #pragma comment(lib,"opencv_highgui2410d.lib")             #pragma comment(lib,"opencv_imgproc2410d.lib")    using namespace std; using namespace cv; // Global variables // Flags updated according to left mouse button activity bool ldown = false, lup = false; // Original image Mat img; // Starting and ending points of the user's selection Point corner1, corner2; // ROI Rect box; // Callback function for mouse events static void mouse_callback(int event, int x, int y, int, void *) {  // When the left mouse button is pressed, record its position and save it in corner1  if(event == EVENT_LBUTTONDOWN)  {   ldown = true;   corner1.x = x;   corner1.y = y;   cout << "Corner 1 recorded at " << corner1 << endl;  }  // When the left mouse button is released, record its position and save it in corner2  if(event == EVENT_LBUTTONUP)  {   // Also check if user selection is bigger than 20 pixels (jut for fun!)   if(abs(x - corner1.x) > 20 && abs(y - corner1.y) > 20)   {    lup = true;    corner2.x = x;    corner2.y = y;    cout << "Corner 2 recorded at " << corner2 << endl << endl;   }   else   {    cout << "Please select a bigger region" << endl;    ldown = false;   }  }  // Update the box showing the selected region as the user drags the mouse  if(ldown == true && lup == false)  {   Point pt;   pt.x = x;   pt.y = y;   Mat local_img = img.clone();   rectangle(local_img, corner1, pt, Scalar(0, 0, 255));   imshow("Cropping app", local_img);  }  // Define ROI and crop it out when both corners have been selected  if(ldown == true && lup == true)  {   box.width = abs(corner1.x - corner2.x);   box.height = abs(corner1.y - corner2.y);   box.x = min(corner1.x, corner2.x);   box.y = min(corner1.y, corner2.y);   // Make an image out of just the selected ROI and display it in a new window   Mat crop(img, box);   namedWindow("Crop");   imshow("Crop", crop);   ldown = false;   lup = false;  } } int main() {  img = imread("swan.jpg");  namedWindow("Cropping app");  imshow("Cropping app", img);  // Set the mouse event callback function  setMouseCallback("Cropping app", mouse_callback);  // Exit by pressing 'q'  while(char(waitKey(1)) != 'q') {}  return 0; }

裁切效果：