image_util_webp.cpp

/*****************************************************************************
 *
 * This file is part of Mapnik (c++ mapping toolkit)
 *
 * Copyright (C) 2024 Artem Pavlenko
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 *****************************************************************************/

// mapnik
#if defined(HAVE_WEBP)
#include <mapnik/webp_io.hpp>
#endif

#include <mapnik/image_util.hpp>
#include <mapnik/image_util_webp.hpp>
#include <mapnik/image.hpp>
#include <mapnik/image_any.hpp>
#include <mapnik/image_view.hpp>
#include <mapnik/image_options.hpp>
#include <mapnik/util/conversions.hpp>

// stl
#include <string>
#include <iostream>

namespace mapnik {

#if defined(HAVE_WEBP)
void handle_webp_options(std::string const& type, WebPConfig& config, bool& alpha)
{
    if (type == "webp")
    {
        return;
    }
    if (type.length() > 4)
    {
        for (auto const& kv : parse_image_options(type))
        {
            auto const& key = kv.first;
            auto const& val = kv.second;

            if (key == "webp")
                continue;
            else if (key == "quality")
            {
                if (val && !(*val).empty())
                {
                    double quality = 90;
                    if (!mapnik::util::string2double(*val, quality) || quality < 0.0 || quality > 100.0)
                    {
                        throw image_writer_exception("invalid webp quality: '" + *val + "'");
                    }
                    config.quality = static_cast<float>(quality);
                }
            }
            else if (key == "method")
            {
                if (val && !(*val).empty())
                {
                    if (!mapnik::util::string2int(*val, config.method) || config.method < 0 || config.method > 6)
                    {
                        throw image_writer_exception("invalid webp method: '" + *val + "'");
                    }
                }
            }
            else if (key == "lossless")
            {
                if (val && !(*val).empty())
                {
#if (WEBP_ENCODER_ABI_VERSION >> 8) >= 1 // >= v0.1.99 / 0x0100
                    if (!mapnik::util::string2int(*val, config.lossless) || config.lossless < 0 || config.lossless > 1)
                    {
                        throw image_writer_exception("invalid webp lossless: '" + *val + "'");
                    }
#else
#ifdef _MSC_VER
#pragma NOTE(compiling against webp that does not support the lossless flag)
#else
#warning "compiling against webp that does not support the lossless flag"
#endif
                    throw image_writer_exception("your webp version does not support the lossless option");
#endif
                }
            }
            else if (key == "image_hint")
            {
                if (val && !(*val).empty())
                {
#if (WEBP_ENCODER_ABI_VERSION >> 8) >= 1 // >= v0.1.99 / 0x0100
                    int image_hint = 0;
                    if (!mapnik::util::string2int(*val, image_hint) || image_hint < 0 || image_hint > 3)
                    {
                        throw image_writer_exception("invalid webp image_hint: '" + *val + "'");
                    }
                    config.image_hint = static_cast<WebPImageHint>(image_hint);
#else
#ifdef _MSC_VER
#pragma NOTE(compiling against webp that does not support the image_hint flag)
#else
#warning "compiling against webp that does not support the image_hint flag"
#endif
                    throw image_writer_exception("your webp version does not support the image_hint option");
#endif
                }
            }
            else if (key == "alpha")
            {
                if (val && !(*val).empty())
                {
                    if (!mapnik::util::string2bool(*val, alpha))
                    {
                        throw image_writer_exception("invalid webp alpha: '" + *val + "'");
                    }
                }
            }
            else if (key == "target_size")
            {
                if (val && !(*val).empty())
                {
                    if (!mapnik::util::string2int(*val, config.target_size))
                    {
                        throw image_writer_exception("invalid webp target_size: '" + *val + "'");
                    }
                }
            }
            else if (key == "target_psnr")
            {
                if (val && !(*val).empty())
                {
                    double psnr = 0;
                    if (!mapnik::util::string2double(*val, psnr))
                    {
                        throw image_writer_exception("invalid webp target_psnr: '" + *val + "'");
                    }
                    config.target_PSNR = psnr;
                }
            }
            else if (key == "segments")
            {
                if (val && !(*val).empty())
                {
                    if (!mapnik::util::string2int(*val, config.segments))
                    {
                        throw image_writer_exception("invalid webp segments: '" + *val + "'");
                    }
                }
            }
            else if (key == "sns_strength")
            {
                if (val && !(*val).empty())
                {
                    if (!mapnik::util::string2int(*val, config.sns_strength))
                    {
                        throw image_writer_exception("invalid webp sns_strength: '" + *val + "'");
                    }
                }
            }
            else if (key == "filter_strength")
            {
                if (val && !(*val).empty())
                {
                    if (!mapnik::util::string2int(*val, config.filter_strength))
                    {
                        throw image_writer_exception("invalid webp filter_strength: '" + *val + "'");
                    }
                }
            }
            else if (key == "filter_sharpness")
            {
                if (val && !(*val).empty())
                {
                    if (!mapnik::util::string2int(*val, config.filter_sharpness))
                    {
                        throw image_writer_exception("invalid webp filter_sharpness: '" + *val + "'");
                    }
                }
            }
            else if (key == "filter_type")
            {
                if (val && !(*val).empty())
                {
                    if (!mapnik::util::string2int(*val, config.filter_type))
                    {
                        throw image_writer_exception("invalid webp filter_type: '" + *val + "'");
                    }
                }
            }
            else if (key == "autofilter")
            {
                if (val && !(*val).empty())
                {
                    if (!mapnik::util::string2int(*val, config.autofilter))
                    {
                        throw image_writer_exception("invalid webp autofilter: '" + *val + "'");
                    }
                }
            }
            else if (key == "alpha_compression")
            {
                if (val && !(*val).empty())
                {
                    if (!mapnik::util::string2int(*val, config.alpha_compression))
                    {
                        throw image_writer_exception("invalid webp alpha_compression: '" + *val + "'");
                    }
                }
            }
            else if (key == "alpha_filtering")
            {
                if (val && !(*val).empty())
                {
#if (WEBP_ENCODER_ABI_VERSION >> 8) >= 1 // >= v0.1.99 / 0x0100
                    if (!mapnik::util::string2int(*val, config.alpha_filtering))
                    {
                        throw image_writer_exception("invalid webp alpha_filtering: '" + *val + "'");
                    }
#else
#ifdef _MSC_VER
#pragma NOTE(compiling against webp that does not support the alpha_filtering flag)
#else
#warning "compiling against webp that does not support the alpha_filtering flag"
#endif
                    throw image_writer_exception("your webp version does not support the alpha_filtering option");
#endif
                }
            }
            else if (key == "alpha_quality")
            {
                if (val && !(*val).empty())
                {
#if (WEBP_ENCODER_ABI_VERSION >> 8) >= 1 // >= v0.1.99 / 0x0100
                    if (!mapnik::util::string2int(*val, config.alpha_quality))
                    {
                        throw image_writer_exception("invalid webp alpha_quality: '" + *val + "'");
                    }
#else
#ifdef _MSC_VER
#pragma NOTE(compiling against webp that does not support the alpha_quality flag)
#else
#warning "compiling against webp that does not support the alpha_quality flag"
#endif
                    throw image_writer_exception("your webp version does not support the alpha_quality option");
#endif
                }
            }
            else if (key == "pass")
            {
                if (val && !(*val).empty())
                {
                    if (!mapnik::util::string2int(*val, config.pass))
                    {
                        throw image_writer_exception("invalid webp pass: '" + *val + "'");
                    }
                }
            }
            else if (key == "preprocessing")
            {
                if (val && !(*val).empty())
                {
                    if (!mapnik::util::string2int(*val, config.preprocessing))
                    {
                        throw image_writer_exception("invalid webp preprocessing: '" + *val + "'");
                    }
                }
            }
            else if (key == "partitions")
            {
                if (val && !(*val).empty())
                {
                    if (!mapnik::util::string2int(*val, config.partitions))
                    {
                        throw image_writer_exception("invalid webp partitions: '" + *val + "'");
                    }
                }
            }
            else if (key == "partition_limit")
            {
                if (val && !(*val).empty())
                {
                    if (!mapnik::util::string2int(*val, config.partition_limit))
                    {
                        throw image_writer_exception("invalid webp partition_limit: '" + *val + "'");
                    }
                }
            }
            else
            {
                throw image_writer_exception("unhandled webp option: " + key);
            }
        }
    }
}
#endif

webp_saver::webp_saver(std::ostream& stream, std::string const& t)
    : stream_(stream)
    , t_(t)
{}

template<>
void webp_saver::operator()<image_null>(image_null const& image) const
{
    throw image_writer_exception("null images not supported");
}

template<>
void webp_saver::operator()<image_view_null>(image_view_null const& image) const
{
    throw image_writer_exception("null image views not supported");
}

template<typename T>
void process_rgba8_webp(T const& image, std::string const& t, std::ostream& stream)
{
#if defined(HAVE_WEBP)
    WebPConfig config;
    // Default values set here will be lossless=0 and quality=75 (as least as of webp v0.3.1)
    if (!WebPConfigInit(&config))
    {
        throw std::runtime_error("version mismatch");
    }
    // see for more details: https://github.com/mapnik/mapnik/wiki/Image-IO#webp-output-options
    bool alpha = true;
    handle_webp_options(t, config, alpha);
    save_as_webp(stream, image, config, alpha);
#else
    throw image_writer_exception("webp output is not enabled in your build of Mapnik");
#endif
}

template<>
void webp_saver::operator()<image_rgba8>(image_rgba8 const& image) const
{
    process_rgba8_webp(image, t_, stream_);
}

template<>
void webp_saver::operator()<image_view_rgba8>(image_view_rgba8 const& image) const
{
    process_rgba8_webp(image, t_, stream_);
}

template<typename T>
void webp_saver::operator()(T const& image) const
{
    throw image_writer_exception("Mapnik does not support webp grayscale images");
}

template void webp_saver::operator()<image_gray8>(image_gray8 const& image) const;
template void webp_saver::operator()<image_gray8s>(image_gray8s const& image) const;
template void webp_saver::operator()<image_gray16>(image_gray16 const& image) const;
template void webp_saver::operator()<image_gray16s>(image_gray16s const& image) const;
template void webp_saver::operator()<image_gray32>(image_gray32 const& image) const;
template void webp_saver::operator()<image_gray32s>(image_gray32s const& image) const;
template void webp_saver::operator()<image_gray32f>(image_gray32f const& image) const;
template void webp_saver::operator()<image_gray64>(image_gray64 const& image) const;
template void webp_saver::operator()<image_gray64s>(image_gray64s const& image) const;
template void webp_saver::operator()<image_gray64f>(image_gray64f const& image) const;
template void webp_saver::operator()<image_view_gray8>(image_view_gray8 const& image) const;
template void webp_saver::operator()<image_view_gray8s>(image_view_gray8s const& image) const;
template void webp_saver::operator()<image_view_gray16>(image_view_gray16 const& image) const;
template void webp_saver::operator()<image_view_gray16s>(image_view_gray16s const& image) const;
template void webp_saver::operator()<image_view_gray32>(image_view_gray32 const& image) const;
template void webp_saver::operator()<image_view_gray32s>(image_view_gray32s const& image) const;
template void webp_saver::operator()<image_view_gray32f>(image_view_gray32f const& image) const;
template void webp_saver::operator()<image_view_gray64>(image_view_gray64 const& image) const;
template void webp_saver::operator()<image_view_gray64s>(image_view_gray64s const& image) const;
template void webp_saver::operator()<image_view_gray64f>(image_view_gray64f const& image) const;

} // namespace mapnik