png_rgba_image_saver.cpp

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#include "porytiles2/infra/services/png_rgba_image_saver.hpp"
 
#include <expected>
#include <filesystem>
#include <string>
 
#include "CImg.h"
#include "fmt/format.h"
 
#include "porytiles2/domain/models/image.hpp"
#include "porytiles2/domain/models/rgba32.hpp"
#include "porytiles2/xcut/result/chainable_result.hpp"
 
namespace porytiles2 {
 
using cimg_library::CImg;
using cimg_library::CImgException;
 
ChainableResult<void>
PngRgbaImageSaver::save_to_file(const Image<Rgba32> &image, const std::filesystem::path &path) const
{
    const auto width = static_cast<int>(image.width());
    const auto height = static_cast<int>(image.height());
    constexpr auto spectrum = 4; // RGBA
 
    // Cannot use braced initializer here, it confuses the compiler
    CImg<std::uint8_t> cimg_png(width, height, 1, spectrum);
 
    for (std::size_t row = 0; row < image.height(); ++row) {
        for (std::size_t col = 0; col < image.width(); ++col) {
            const auto pixel = image.at(row, col);
 
            cimg_png(col, row, 0, 0) = pixel.red();
            cimg_png(col, row, 0, 1) = pixel.green();
            cimg_png(col, row, 0, 2) = pixel.blue();
            cimg_png(col, row, 0, 3) = pixel.alpha();
        }
    }
 
    const auto path_c_str = path.c_str();
    try {
        std::ignore = cimg_png.save_png(path_c_str);
    }
    catch (const std::exception &e) {
        return FormattableError{fmt::format("{}: save failed: {}", path.filename().c_str(), e.what())};
    }
 
    return {};
}
 
} // namespace porytiles2