animation.cpp

/*
 * Copyright (c) 2024, Nico Weber <thakis@chromium.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include <LibCore/ArgsParser.h>
#include <LibCore/File.h>
#include <LibCore/MappedFile.h>
#include <LibGfx/ImageFormats/AnimationWriter.h>
#include <LibGfx/ImageFormats/GIFWriter.h>
#include <LibGfx/ImageFormats/ImageDecoder.h>
#include <LibGfx/ImageFormats/WebPWriter.h>

struct Options {
    StringView in_path;
    StringView out_path;
    bool write_full_frames { false };
    Gfx::AnimationWriter::AllowInterFrameCompression allow_inter_frame_compression { Gfx::AnimationWriter::AllowInterFrameCompression::Yes };
};

static ErrorOr<Options> parse_options(Main::Arguments arguments)
{
    Options options;
    Core::ArgsParser args_parser;
    args_parser.add_positional_argument(options.in_path, "Path to input image file", "FILE");
    args_parser.add_option(options.out_path, "Path to output image file", "output", 'o', "FILE");

    bool inter_frame_compression_full = false;
    args_parser.add_option(inter_frame_compression_full, "Store smallest frame covering all changing pixels between frames, and zero out non-changing pixels. Default.", "inter-frame-compression=full");

    bool inter_frame_compression_clip = false;
    args_parser.add_option(inter_frame_compression_clip, "Store smallest frame covering all changing pixels between frames.", "inter-frame-compression=clip");

    bool inter_frame_compression_none = false;
    args_parser.add_option(inter_frame_compression_none, "Do not store incremental frames. Produces larger files.", "inter-frame-compression=none");

    args_parser.parse(arguments);

    if (options.out_path.is_empty())
        return Error::from_string_view("-o is required "sv);

    if (inter_frame_compression_full + inter_frame_compression_clip + inter_frame_compression_none > 1)
        return Error::from_string_view("Only one of --inter-frame-compression=full, --inter-frame-compression=clip-rect, --inter-frame-compression=none can be specified"sv);
    if (!inter_frame_compression_full && !inter_frame_compression_clip && !inter_frame_compression_none)
        inter_frame_compression_full = true;
    options.write_full_frames = inter_frame_compression_none;
    options.allow_inter_frame_compression = inter_frame_compression_full ? Gfx::AnimationWriter::AllowInterFrameCompression::Yes : Gfx::AnimationWriter::AllowInterFrameCompression::No;

    return options;
}

ErrorOr<int> serenity_main(Main::Arguments arguments)
{
    Options options = TRY(parse_options(arguments));

    // FIXME: Allow multiple single frames as input too, and allow manually setting their duration.

    auto file = TRY(Core::MappedFile::map(options.in_path));
    auto decoder = TRY(Gfx::ImageDecoder::try_create_for_raw_bytes(file->bytes()));
    if (!decoder)
        return Error::from_string_view("Could not find decoder for input file"sv);

    auto output_file = TRY(Core::File::open(options.out_path, Core::File::OpenMode::Write));
    auto output_stream = TRY(Core::OutputBufferedFile::create(move(output_file)));

    auto animation_writer = TRY([&]() -> ErrorOr<NonnullOwnPtr<Gfx::AnimationWriter>> {
        if (options.out_path.ends_with(".webp"sv))
            return Gfx::WebPWriter::start_encoding_animation(*output_stream, decoder->size(), decoder->loop_count());
        if (options.out_path.ends_with(".gif"sv))
            return Gfx::GIFWriter::start_encoding_animation(*output_stream, decoder->size(), decoder->loop_count());
        return Error::from_string_literal("Unable to find a encoder for the requested extension.");
    }());

    RefPtr<Gfx::Bitmap> last_frame;
    for (size_t i = 0; i < decoder->frame_count(); ++i) {
        auto frame = TRY(decoder->frame(i));
        if (options.write_full_frames) {
            TRY(animation_writer->add_frame(*frame.image, frame.duration));
        } else {
            TRY(animation_writer->add_frame_relative_to_last_frame(*frame.image, frame.duration, last_frame, options.allow_inter_frame_compression));
            last_frame = frame.image;
        }
    }

    return 0;
}