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Implement writing png pixmaps

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This commit is contained in:
Nikita Lisitsa 2023-06-06 13:21:50 +03:00
parent 769b5786ae
commit 93e5691d8a
2 changed files with 109 additions and 55 deletions
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2
libs/gfx/include/psemek/gfx/pixmap.hpp
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@ -27,6 +27,8 @@ namespace psemek::gfx
pixmap_rgba read_png(io::istream && is);
pixmap_monochrome read_png_monochrome(io::istream && is);
void write_png(pixmap_rgba const & p, io::ostream && os);
template <typename Pixel, std::size_t N>
auto to_srgb(util::array<Pixel, N> pm, float g = 1.f / 2.2f)
{

52
libs/gfx/source/png.cpp
View file

@ -6,6 +6,9 @@
#include <png.h>
namespace psemek::gfx
{
namespace
{
template <typename Pixel>
@ -80,6 +83,50 @@ namespace psemek::gfx
return result;
}
void write_png_impl(pixmap_rgba const & p, io::ostream & os)
{
png_error_ptr error = [](png_structp, png_const_charp str)
{
throw std::runtime_error(str);
};
png_error_ptr warn = [](png_structp, png_const_charp str)
{
log::warning() << str;
};
auto png = png_create_write_struct(PNG_LIBPNG_VER_STRING, nullptr, error, warn);
if (!png) throw std::runtime_error("png_create_write_struct returned null");
png_set_error_fn(png, nullptr, error, warn);
png_infop info = nullptr;
[[maybe_unused]] auto png_dtor = util::at_scope_exit([&]{
png_destroy_write_struct(&png, &info);
});
info = png_create_info_struct(png);
if (!info) throw std::runtime_error("png_create_info_struct returned null");
png_rw_ptr write = [](png_structp png, png_bytep ptr, size_t count){
reinterpret_cast<io::ostream *>(png_get_io_ptr(png))->write(reinterpret_cast<char const *>(ptr), count);
};
png_flush_ptr flush = [](png_structp png){
reinterpret_cast<io::ostream *>(png_get_io_ptr(png))->flush();
};
png_set_write_fn(png, &os, write, flush);
png_set_IHDR(png, info, p.width(), p.height(), 8, PNG_COLOR_TYPE_RGBA, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
png_write_info(png, info);
for (std::uint32_t i = 0; i < p.height(); ++i)
png_write_row(png, reinterpret_cast<png_byte const *>(p.data() + p.width() * i));
}
}
pixmap_rgba read_png(io::istream && is)
{
return read_png_impl<color_rgba>(is, false);
@ -90,4 +137,9 @@ namespace psemek::gfx
return read_png_impl<std::uint8_t>(is, true);
}
void write_png(pixmap_rgba const & p, io::ostream && os)
{
write_png_impl(p, os);
}
}