follow this tutorial. i ran the install-opencv.sh file in bash. its in the tutorial
read the example from openCV
CMakeLists.txt
cmake_minimum_required(VERSION 3.7)
project(openCVTest)
# cmake needs this line
cmake_minimum_required(VERSION 2.8)
# Define project name
project(opencv_example_project)
# Find OpenCV, you may need to set OpenCV_DIR variable
# to the absolute path to the directory containing OpenCVConfig.cmake file
# via the command line or GUI
find_package(OpenCV REQUIRED)
# If the package has been found, several variables will
# be set, you can find the full list with descriptions
# in the OpenCVConfig.cmake file.
# Print some message showing some of them
message(STATUS "OpenCV library status:")
message(STATUS " version: ${OpenCV_VERSION}")
message(STATUS " libraries: ${OpenCV_LIBS}")
message(STATUS " include path: ${OpenCV_INCLUDE_DIRS}")
if(CMAKE_VERSION VERSION_LESS "2.8.11")
# Add OpenCV headers location to your include paths
include_directories(${OpenCV_INCLUDE_DIRS})
endif()
# Declare the executable target built from your sources
add_executable(main main.cpp)
# Link your application with OpenCV libraries
target_link_libraries(main ${OpenCV_LIBS})
main.cpp
/**
* @file LinearBlend.cpp
* @brief Simple linear blender ( dst = alpha*src1 + beta*src2 )
* @author OpenCV team
*/
#include "opencv2/imgcodecs.hpp"
#include "opencv2/highgui.hpp"
#include <stdio.h>
using namespace cv;
/** Global Variables */
const int alpha_slider_max = 100;
int alpha_slider;
double alpha;
double beta;
/** Matrices to store images */
Mat src1;
Mat src2;
Mat dst;
//![on_trackbar]
/**
* @function on_trackbar
* @brief Callback for trackbar
*/
static void on_trackbar( int, void* )
{
alpha = (double) alpha_slider/alpha_slider_max ;
beta = ( 1.0 - alpha );
addWeighted( src1, alpha, src2, beta, 0.0, dst);
imshow( "Linear Blend", dst );
}
//![on_trackbar]
/**
* @function main
* @brief Main function
*/
int main( void )
{
//![load]
/// Read images ( both have to be of the same size and type )
src1 = imread("../data/LinuxLogo.jpg");
src2 = imread("../data/WindowsLogo.jpg");
//![load]
if( src1.empty() ) { printf("Error loading src1 \n"); return -1; }
if( src2.empty() ) { printf("Error loading src2 \n"); return -1; }
/// Initialize values
alpha_slider = 0;
//![window]
namedWindow("Linear Blend", WINDOW_AUTOSIZE); // Create Window
//![window]
//![create_trackbar]
char TrackbarName[50];
sprintf( TrackbarName, "Alpha x %d", alpha_slider_max );
createTrackbar( TrackbarName, "Linear Blend", &alpha_slider, alpha_slider_max, on_trackbar );
//![create_trackbar]
/// Show some stuff
on_trackbar( alpha_slider, 0 );
/// Wait until user press some key
waitKey(0);
return 0;
}
Tested in linux mint 17