| OpenCV 3.4.3 Open Source Computer Vision

samples/cpp/tutorial_code/ImgProc/Pyramids/Pyramids.cpp

An example using pyrDown and pyrUp functions

#include "iostream"
#include "opencv2/imgproc.hpp"
#include "opencv2/imgcodecs.hpp"
#include "opencv2/highgui.hpp"
using namespace std;
using namespace cv;
const char* window_name = "Pyramids Demo";
int main( int argc, char** argv )
{
cout << "\n Zoom In-Out demo \n "
"------------------ \n"
" * [i] -> Zoom in \n"
" * [o] -> Zoom out \n"
" * [ESC] -> Close program \n" << endl;
const char* filename = argc >=2 ? argv[1] : "../data/chicky_512.png";
// Loads an image
Mat src = imread( filename );
// Check if image is loaded fine
if(src.empty()){
printf(" Error opening image\n");
printf(" Program Arguments: [image_name -- default ../data/chicky_512.png] \n");
return -1;
}
for(;;)
{
imshow( window_name, src );
char c = (char)waitKey(0);
if( c == 27 )
{ break; }
else if( c == 'i' )
{ pyrUp( src, src, Size( src.cols*2, src.rows*2 ) );
printf( "** Zoom In: Image x 2 \n" );
}
else if( c == 'o' )
{ pyrDown( src, src, Size( src.cols/2, src.rows/2 ) );
printf( "** Zoom Out: Image / 2 \n" );
}
}
return 0;
}