Is it possible to delete trackbar in OpenCV?

Question

I want to make a MENU trackbar which change the parameter that the user want to change. So if it is set on "1" the BLUR trackbar appears and we can blur the picture, if "2" the ALPHA and BETA trackbars appear and we can change brightness and contrast but the BLUR trackbar is still visible and we can change blur as well and I want it to be seen only when the MENU trackbar's value is 1. I've tried to do it with 'if', 'switch' and even 'while' but they don't work. It may be possible with erasing other trackbars in exact condition but I haven't found function that do it. Or any ideas how to show just precise trackbar?

Here is a part of the code (.cpp):

#include <opencv2\opencv.hpp>
#include <iostream>

using namespace cv;


const int slider_max = 100, slider2_max = 100, slider3_max = 100, slider5_max = 2;
int slider = 0, slider2 = 0, slider3 = 0, slider5 = 0;

(...)
void transf(int, void*)
{

 (...)

if (slider5 == 0)
{
    setTrackbarPos(ALPHA, name3, 0);
    setTrackbarPos(BETA, name3, 0);
    setTrackbarPos(BLUR, name3, 0);
    imshow(name, before);
}
if (slider5 == 1)
{
    setTrackbarPos(ALPHA, name3, 0);
    setTrackbarPos(BETA, name3, 0);
    createTrackbar(BLUR, name3, &slider, slider_max, blur);
    blur(0,0);
}
if (slider5 == 2)
{
    setTrackbarPos(BLUR, name3, 0);
    createTrackbar(ALPHA, name3, &slider2, slider2_max+100, contrBright);
    createTrackbar(BETA, name3, &slider3, slider3_max, contrBright); 
    contrBright(0,0);
}
}

int main()
{
    (...)

 createTrackbar(MENU, name, &slider5, slider5_max, transf);
 transf(0,0);

 waitKey(0);
 return 0;
 }

Neimsz · Accepted Answer · 2017-03-22T15:49:08.503

There is no way to destroy the trackbar you have created in openCV yet. And there are no way to show only a given trackbar.

Once you have created a trackbar, it will appear in order of creation at the bottom of the window in which you placed them.

Maybe you could manage by calling :

destroyWindow(winname);
namedWindow(winname, FLAGS);
createTrackbar(trackname, winname, &pos, maxBound, callBack);
imshow(winname, img);

Each time you need to delete and create new trackbar. It will destroy the window and the trackbars attached to it. Then create a new window, with the new trackbars.

Hope this will be of some help.

Good luck

Is it possible to delete trackbar in OpenCV?

1 Answers1