Simple Example Using OpenCV By CPP And Python

The article introduces how to display an image by OpenCV in CPlusPlus and Python language.
The user can exit the whole program when he presses the ESC key.

CPP

CMakeLists.txt

macro(use_cxx11)
  if (CMAKE_VERSION VERSION_LESS "3.1")
    if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
      set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=gnu++11")
    endif ()
  else ()
    set (CMAKE_CXX_STANDARD 11)
  endif ()
endmacro(use_cxx11)

cmake_minimum_required(VERSION 2.8)
project( CVLearn )
use_cxx11()
find_package( OpenCV REQUIRED )
add_executable( ${PROJECT_NAME} "main.cpp" )
target_link_libraries( ${PROJECT_NAME} ${OpenCV_LIBS} )

main.cpp

#include <stdio.h>
#include <opencv2/opencv.hpp>

using namespace cv;

int main(int argc, char** argv )
{
    Mat image;
    image = imread( "/Users/weiyang/Desktop/Untitled.png", IMREAD_COLOR );

    if ( !image.data )
    {
        printf("No image data \n");
        return -1;
    }
    namedWindow("Display Image", WINDOW_AUTOSIZE );
    imshow("Display Image", image);

    // break when press ESC
    while( 27 != waitKey(0) ) {  }

    return 0;
}

Python

import cv2

path = r'/Users/weiyang/Desktop/Untitled.png'

image = cv2.imread(path)

window_name = 'image'

cv2.imshow(window_name, image)

# waits for user to press ESC
while 27 != cv2.waitKey(0):
    pass

# closing all open windows
cv2.destroyAllWindows()

Output: