Saturday, June 25, 2016

How to Use Trackbar in OpenCV

Posted by Md. Hanif Ali Sohag on Saturday, June 25, 2016 in | No comments
Trackbar Option in OpenCV
In this tutorial you will learn how to use trackbar in OpenCV.


#include <iostream>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>

using namespace std;
using namespace cv;
// Global variables

const int slider_max = 2;
int slider;
Mat img;
// Callback function for trackbar event

void on_trackbar(int pos, void *)
	Mat img_converted;
	if (pos == 1)
		cvtColor(img, img_converted, CV_RGB2HSV);
	else if (pos==2)
		cvtColor(img, img_converted, CV_RGB2GRAY);
		img_converted = img;

	imshow("Trackbar app", img_converted);

int main()
	img = imread("c://test//image1.jpg");
	namedWindow("Trackbar app");
	imshow("Trackbar app", img);
	slider = 0;

	//create the trackbar GUI for user option
	createTrackbar("Color", "Trackbar app", &slider, slider_max, on_trackbar);

	while (char(waitKey(1)) != 'q') 

	return 0;

Track bar option in OpenCV


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