Expand description
High-level GUI
While OpenCV was designed for use in full-scale applications and can be used within functionally rich UI frameworks (such as Qt*, WinForms*, or Cocoa*) or without any UI at all, sometimes there it is required to try functionality quickly and visualize the results. This is what the HighGUI module has been designed for.
It provides easy interface to:
- Create and manipulate windows that can display images and “remember” their content (no need to handle repaint events from OS).
- Add trackbars to the windows, handle simple mouse events as well as keyboard commands.
Flags related creating and manipulating HighGUI windows and mouse events
OpenGL support
Qt New Functions
This figure explains new functionality implemented with Qt* GUI. The new GUI provides a statusbar, a toolbar, and a control panel. The control panel can have trackbars and buttonbars attached to it. If you cannot see the control panel, press Ctrl+P or right-click any Qt window and select Display properties window.
-
To attach a trackbar, the window name parameter must be NULL.
-
To attach a buttonbar, a button must be created. If the last bar attached to the control panel is a buttonbar, the new button is added to the right of the last button. If the last bar attached to the control panel is a trackbar, or the control panel is empty, a new buttonbar is created. Then, a new button is attached to it.
See below the example used to generate the figure:
int main(int argc, char *argv[])
{
int value = 50;
int value2 = 0;
namedWindow("main1",WINDOW_NORMAL);
namedWindow("main2",WINDOW_AUTOSIZE | WINDOW_GUI_NORMAL);
createTrackbar( "track1", "main1", &value, 255, NULL);
String nameb1 = "button1";
String nameb2 = "button2";
createButton(nameb1,callbackButton,&nameb1,QT_CHECKBOX,1);
createButton(nameb2,callbackButton,NULL,QT_CHECKBOX,0);
createTrackbar( "track2", NULL, &value2, 255, NULL);
createButton("button5",callbackButton1,NULL,QT_RADIOBOX,0);
createButton("button6",callbackButton2,NULL,QT_RADIOBOX,1);
setMouseCallback( "main2",on_mouse,NULL );
Mat img1 = imread("files/flower.jpg");
VideoCapture video;
video.open("files/hockey.avi");
Mat img2,img3;
while( waitKey(33) != 27 )
{
img1.convertTo(img2,-1,1,value);
video >> img3;
imshow("main1",img2);
imshow("main2",img3);
}
destroyAllWindows();
return 0;
}
WinRT support
This figure explains new functionality implemented with WinRT GUI. The new GUI provides an Image control, and a slider panel. Slider panel holds trackbars attached to it.
Sliders are attached below the image control. Every new slider is added below the previous one.
See below the example used to generate the figure:
void sample_app::MainPage::ShowWindow()
{
static cv::String windowName("sample");
cv::winrt_initContainer(this->cvContainer);
cv::namedWindow(windowName); // not required
cv::Mat image = cv::imread("Assets/sample.jpg");
cv::Mat converted = cv::Mat(image.rows, image.cols, CV_8UC4);
cv::cvtColor(image, converted, COLOR_BGR2BGRA);
cv::imshow(windowName, converted); // this will create window if it hasn't been created before
int state = 42;
cv::TrackbarCallback callback = [](int pos, void* userdata)
{
if (pos == 0) {
cv::destroyWindow(windowName);
}
};
cv::TrackbarCallback callbackTwin = [](int pos, void* userdata)
{
if (pos >= 70) {
cv::destroyAllWindows();
}
};
cv::createTrackbar("Sample trackbar", windowName, &state, 100, callback);
cv::createTrackbar("Twin brother", windowName, &state, 100, callbackTwin);
}