OpenCV3添加滑动条和鼠标事件到图形界面

鼠标事件和滑动条控制在计算机视觉和OpenCV中非常有用，使用这些控件，用户可以直接与图形界面交互，改变输入图像或者变量的属性值。

 /*

     In this section, we are going to introduce you to the concepts of adding slider and

 mouse events for basic interactions. To understand this correctly, we will create a small

 project, where we paint green circles in the image using the mouse events and blur the

 image with slider.

 */

 #include <opencv2/core.hpp>

 #include <opencv2/highgui.hpp>

 #include <opencv2/imgproc.hpp>

 using namespace cv;

 // Create a variable to save the position value in track

 int blurAmount = ;

 // Trackbar call back function

 static void onChange(int pos, void* userInput);

 // Mouse callback

 static void onMouse(int event, int x, int y, int, void* userInput);

 int main(int argc, const char** argv)

 {

     // Read images

     Mat boy = imread("../images/eating.jpg");

     // Create windows

     namedWindow("Boy");

     // Create a trackbar

     createTrackbar("Boy", "Boy", &blurAmount, , onChange, &boy);

     setMouseCallback("Boy", onMouse, &boy);

     // Call to onChange to init

     onChange(blurAmount, &boy);

     // wait app for a key to exit

     waitKey();

     // Destroy the windows

     destroyWindow("Boy");

     return ;

 }

 // Trackbar call back function

 static void onChange(int pos, void* userInput)

 {

     if (pos <= ) return;

     // Aux variable for result

     Mat imgBlur;

     // Get the pointer input image

     Mat* image = (Mat*)userInput;

     // Apply a blur filter

     blur(*image, imgBlur, Size(pos, pos));

     // Show the result

     imshow("Boy", imgBlur);

 }

 // Mouse callback

 static void onMouse(int event, int x, int y, int, void* userInput)

 {

     if (event != EVENT_LBUTTONDOWN) return;

     // Get the pointer input image

     Mat *image = (Mat*)userInput;

     // Draw circle

     circle(*image, Point(x, y), , Scalar(, , ), );

     // Call onChange to get blurred image

     onChange(blurAmount, image);

 }

程序运行效果如下：