99 lines
3.3 KiB
C++
99 lines
3.3 KiB
C++
/*
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Copyright (c) 2020 CNRS
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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1. Redistributions of source code must retain the above copyright notice, this
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list of conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright notice,
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this list of conditions and the following disclaimer in the documentation
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and/or other materials provided with the distribution.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIEDi
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
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ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <iostream>
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#include <string>
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#include <random>
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#include <vector>
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//Command-line parsing
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#include <CLI11.hpp>
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//Image filtering and I/O
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#define cimg_display 0
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#include <CImg.h>
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#define STB_IMAGE_IMPLEMENTATION
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#include <stb_image.h>
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#define STB_IMAGE_WRITE_IMPLEMENTATION
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#include <stb_image_write.h>
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//Global flag to silent verbose messages
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bool silent;
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int main(int argc, char **argv)
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{
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CLI::App app{"grayscale"};
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std::string sourceImage;
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app.add_option("-s,--source", sourceImage, "Source image")->required()->check(CLI::ExistingFile);;
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std::string outputImage= "output.png";
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app.add_option("-o,--output", outputImage, "Output image")->required();
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unsigned int nbSteps = 3;
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app.add_option("-n,--nbsteps", nbSteps, "Number of sliced steps (3)");
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silent = false;
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app.add_flag("--silent", silent, "No verbose messages");
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CLI11_PARSE(app, argc, argv);
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//Image loading
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int width,height, nbChannels;
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unsigned char *source = stbi_load(sourceImage.c_str(), &width, &height, &nbChannels, 0);
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if (!silent) std::cout<< "Source image: "<<width<<"x"<<height<<" ("<<nbChannels<<")"<< std::endl;
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if (nbChannels < 3)
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{
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std::cout<< "Input images must be RGB images."<<std::endl;
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exit(1);
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}
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//Main computation
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std::vector<unsigned char> output(width*height);
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// to grayscale
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for(auto i = 0 ; i < width ; ++i)
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{
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for(auto j = 0; j < height; ++j)
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{
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auto indexPixel = nbChannels*(width*j+i);
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unsigned char r = source[ indexPixel ];
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unsigned char g = source[ indexPixel + 1];
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unsigned char b = source[ indexPixel + 2];
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unsigned char avg = (0.21*r+0.72*g+0.07*b);
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//Swapping the channels
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output[ width*j+i ] = avg;
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}
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}
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//Final export
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if (!silent) std::cout<<"Exporting.."<<std::endl;
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int errcode = stbi_write_png(outputImage.c_str(), width, height, 1, output.data(), width);
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if (!errcode)
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{
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std::cout<<"Error while exporting the resulting image."<<std::endl;
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exit(errcode);
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}
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stbi_image_free(source);
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exit(0);
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}
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