Working with PNG files in C++
I’m working on MacOS X, so first of all I need to compile and install the libraries (libpng and png++):
1 2 3 4 5 6 7 8 9 10 11 12 13 | tar xvzf libpng-1.5.7.tar.gzcd libpng-1.5.7./configuremakesudo make install#Download png++curl http://download.savannah.nongnu.org/releases/pngpp/png++-0.2.5.tar.gz > ./png++.tar.gztar xzvf png++.tar.gzcd png++-0.2.5makesudo make install |
Everything should be installed now, and we can write some code. Create the following C++ program:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | #include <png++/png.hpp>int main() { png::image< png::rgb_pixel > image("input.png"); for (size_t y = 0; y < image.get_height(); ++y) { for (size_t x = 0; x < image.get_width(); ++x) { if(((x+y)%2) == 0) image[x][y] = png::rgb_pixel(0, 0, 0); } } image.write("output.png");} |
The program loads a file called input.png, sets every other pixel to black and writes it to output.png. Compile and run as follows:
1 2 | g++ test.cpp -lpng./a.out |
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