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https://github.com/LadybirdBrowser/ladybird.git
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LibGfx: Add a GIF writer
This version is really barebone as it does not support colors (only black and white) or animated images.
This commit is contained in:
parent
54f33b43c6
commit
2513a1b83f
Notes:
sideshowbarker
2024-07-17 05:23:40 +09:00
Author: https://github.com/LucasChollet Commit: https://github.com/SerenityOS/serenity/commit/2513a1b83f Pull-request: https://github.com/SerenityOS/serenity/pull/24191 Reviewed-by: https://github.com/nico ✅ Reviewed-by: https://github.com/timschumi
@ -12,6 +12,8 @@
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#include <LibGfx/ImageFormats/AnimationWriter.h>
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#include <LibGfx/ImageFormats/BMPLoader.h>
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#include <LibGfx/ImageFormats/BMPWriter.h>
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#include <LibGfx/ImageFormats/GIFLoader.h>
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#include <LibGfx/ImageFormats/GIFWriter.h>
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#include <LibGfx/ImageFormats/JPEGLoader.h>
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#include <LibGfx/ImageFormats/JPEGWriter.h>
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#include <LibGfx/ImageFormats/PNGLoader.h>
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@ -22,21 +24,22 @@
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#include <LibGfx/ImageFormats/WebPWriter.h>
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#include <LibTest/TestCase.h>
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static ErrorOr<NonnullRefPtr<Gfx::Bitmap>> expect_single_frame(Gfx::ImageDecoderPlugin& plugin_decoder)
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static ErrorOr<NonnullRefPtr<Gfx::Bitmap>> expect_single_frame(Gfx::ImageDecoderPlugin& plugin_decoder, bool is_gif)
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{
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EXPECT_EQ(plugin_decoder.frame_count(), 1u);
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EXPECT(!plugin_decoder.is_animated());
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EXPECT(!plugin_decoder.loop_count());
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EXPECT_EQ(plugin_decoder.loop_count(), is_gif ? 1u : 0u);
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auto frame_descriptor = TRY(plugin_decoder.frame(0));
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EXPECT_EQ(frame_descriptor.duration, 0);
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if (!is_gif)
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EXPECT_EQ(frame_descriptor.duration, 0);
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return *frame_descriptor.image;
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}
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static ErrorOr<NonnullRefPtr<Gfx::Bitmap>> expect_single_frame_of_size(Gfx::ImageDecoderPlugin& plugin_decoder, Gfx::IntSize size)
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static ErrorOr<NonnullRefPtr<Gfx::Bitmap>> expect_single_frame_of_size(Gfx::ImageDecoderPlugin& plugin_decoder, Gfx::IntSize size, bool is_gif = false)
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{
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EXPECT_EQ(plugin_decoder.size(), size);
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auto frame = TRY(expect_single_frame(plugin_decoder));
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auto frame = TRY(expect_single_frame(plugin_decoder, is_gif));
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EXPECT_EQ(frame->size(), size);
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return frame;
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}
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@ -54,10 +57,10 @@ static ErrorOr<ByteBuffer> encode_bitmap(Gfx::Bitmap const& bitmap, ExtraArgs...
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}
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template<class Writer, class Loader>
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static ErrorOr<NonnullRefPtr<Gfx::Bitmap>> get_roundtrip_bitmap(Gfx::Bitmap const& bitmap)
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static ErrorOr<NonnullRefPtr<Gfx::Bitmap>> get_roundtrip_bitmap(Gfx::Bitmap const& bitmap, bool is_gif = false)
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{
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auto encoded_data = TRY(encode_bitmap<Writer>(bitmap));
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return expect_single_frame_of_size(*TRY(Loader::create(encoded_data)), bitmap.size());
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return expect_single_frame_of_size(*TRY(Loader::create(encoded_data)), bitmap.size(), is_gif);
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}
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static void expect_bitmaps_equal(Gfx::Bitmap const& a, Gfx::Bitmap const& b)
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@ -69,9 +72,9 @@ static void expect_bitmaps_equal(Gfx::Bitmap const& a, Gfx::Bitmap const& b)
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}
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template<class Writer, class Loader>
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static ErrorOr<void> test_roundtrip(Gfx::Bitmap const& bitmap)
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static ErrorOr<void> test_roundtrip(Gfx::Bitmap const& bitmap, bool is_gif = false)
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{
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auto decoded = TRY((get_roundtrip_bitmap<Writer, Loader>(bitmap)));
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auto decoded = TRY((get_roundtrip_bitmap<Writer, Loader>(bitmap, is_gif)));
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expect_bitmaps_equal(*decoded, bitmap);
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return {};
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}
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@ -108,6 +111,18 @@ TEST_CASE(test_bmp)
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TRY_OR_FAIL((test_roundtrip<Gfx::BMPWriter, Gfx::BMPImageDecoderPlugin>(TRY_OR_FAIL(create_test_rgba_bitmap()))));
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}
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TEST_CASE(test_gif)
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{
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// We only support grayscale and non-animated images yet
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auto bitmap = TRY_OR_FAIL(create_test_rgb_bitmap());
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// Convert bitmap to grayscale
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for (auto& argb : *bitmap)
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argb = Color::from_argb(argb).to_grayscale().value();
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TRY_OR_FAIL((test_roundtrip<Gfx::GIFWriter, Gfx::GIFImageDecoderPlugin>(bitmap, true)));
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}
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TEST_CASE(test_jpeg)
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{
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// JPEG is lossy, so the roundtripped bitmap won't match the original bitmap. But it should still have the same size.
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@ -43,6 +43,7 @@ set(SOURCES
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ImageFormats/CCITTDecoder.cpp
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ImageFormats/DDSLoader.cpp
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ImageFormats/GIFLoader.cpp
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ImageFormats/GIFWriter.cpp
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ImageFormats/ICOLoader.cpp
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ImageFormats/ILBMLoader.cpp
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ImageFormats/ImageDecoder.cpp
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150
Userland/Libraries/LibGfx/ImageFormats/GIFWriter.cpp
Normal file
150
Userland/Libraries/LibGfx/ImageFormats/GIFWriter.cpp
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@ -0,0 +1,150 @@
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/*
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* Copyright (c) 2024, Lucas Chollet <lucas.chollet@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/BitStream.h>
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#include <LibCompress/Lzw.h>
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#include <LibGfx/Bitmap.h>
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#include <LibGfx/ImageFormats/GIFWriter.h>
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namespace Gfx {
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namespace {
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ErrorOr<void> write_header(Stream& stream)
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{
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// 17. Header
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TRY(stream.write_until_depleted("GIF87a"sv));
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return {};
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}
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ErrorOr<void> write_logical_descriptor(BigEndianOutputBitStream& stream, Bitmap const& bitmap)
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{
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// 18. Logical Screen Descriptor
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if (bitmap.width() > NumericLimits<u16>::max() || bitmap.height() > NumericLimits<u16>::max())
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return Error::from_string_literal("Bitmap size is too big for a GIF");
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TRY(stream.write_value<u16>(bitmap.width()));
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TRY(stream.write_value<u16>(bitmap.height()));
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// Global Color Table Flag
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TRY(stream.write_bits(true, 1));
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// Color Resolution
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TRY(stream.write_bits(6u, 3));
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// Sort Flag
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TRY(stream.write_bits(false, 1));
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// Size of Global Color Table
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TRY(stream.write_bits(7u, 3));
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// Background Color Index
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TRY(stream.write_value<u8>(0));
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// Pixel Aspect Ratio
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// NOTE: We can write a zero as most decoders discard the value.
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TRY(stream.write_value<u8>(0));
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return {};
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}
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ErrorOr<void> write_global_color_table(Stream& stream)
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{
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// 19. Global Color Table
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// FIXME: The color table should include color specific to the image
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for (u16 i = 0; i < 256; ++i) {
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TRY(stream.write_value<u8>(i));
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TRY(stream.write_value<u8>(i));
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TRY(stream.write_value<u8>(i));
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}
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return {};
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}
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ErrorOr<void> write_image_data(Stream& stream, Bitmap const& bitmap)
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{
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// 22. Table Based Image Data
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auto const pixel_number = static_cast<u32>(bitmap.width() * bitmap.height());
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auto indexes = TRY(ByteBuffer::create_uninitialized(pixel_number));
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for (u32 i = 0; i < pixel_number; ++i) {
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auto const color = Color::from_argb(*(bitmap.begin() + i));
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if (color.red() != color.green() || color.green() != color.blue())
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return Error::from_string_literal("Non grayscale images are unsupported.");
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indexes[i] = Color::from_argb(*(bitmap.begin() + i)).red(); // Any channel is correct
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}
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constexpr u8 lzw_minimum_code_size = 8;
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auto const encoded = TRY(Compress::LzwCompressor::compress_all(move(indexes), lzw_minimum_code_size));
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auto const number_of_subblocks = ceil_div(encoded.size(), 255ul);
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TRY(stream.write_value<u8>(lzw_minimum_code_size));
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for (u32 i = 0; i < number_of_subblocks; ++i) {
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auto const offset = i * 255;
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auto const to_write = min(255, encoded.size() - offset);
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TRY(stream.write_value<u8>(to_write));
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TRY(stream.write_until_depleted(encoded.bytes().slice(offset, to_write)));
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}
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// Block terminator
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TRY(stream.write_value<u8>(0));
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return {};
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}
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ErrorOr<void> write_image_descriptor(BigEndianOutputBitStream& stream, Bitmap const& bitmap)
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{
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// 20. Image Descriptor
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// Image Separator
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TRY(stream.write_value<u8>(0x2c));
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// Image Left Position
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TRY(stream.write_value<u16>(0));
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// Image Top Position
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TRY(stream.write_value<u16>(0));
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// Image Width
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TRY(stream.write_value<u16>(bitmap.width()));
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// Image Height
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TRY(stream.write_value<u16>(bitmap.height()));
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// Local Color Table Flag
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TRY(stream.write_bits(false, 1));
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// Interlace Flag
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TRY(stream.write_bits(false, 1));
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// Sort Flag
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TRY(stream.write_bits(false, 1));
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// Reserved
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TRY(stream.write_bits(0u, 2));
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// Size of Local Color Table
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TRY(stream.write_bits(0u, 3));
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return {};
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}
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ErrorOr<void> write_trailer(Stream& stream)
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{
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TRY(stream.write_value<u8>(0x3B));
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return {};
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}
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}
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ErrorOr<void> GIFWriter::encode(Stream& stream, Bitmap const& bitmap)
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{
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TRY(write_header(stream));
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BigEndianOutputBitStream bit_stream { MaybeOwned<Stream> { stream } };
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TRY(write_logical_descriptor(bit_stream, bitmap));
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TRY(write_global_color_table(bit_stream));
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// Write a Table-Based Image
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TRY(write_image_descriptor(bit_stream, bitmap));
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TRY(write_image_data(stream, bitmap));
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TRY(write_trailer(bit_stream));
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return {};
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}
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}
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Userland/Libraries/LibGfx/ImageFormats/GIFWriter.h
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21
Userland/Libraries/LibGfx/ImageFormats/GIFWriter.h
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@ -0,0 +1,21 @@
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/*
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* Copyright (c) 2024, Lucas Chollet <lucas.chollet@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/Error.h>
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#include <LibGfx/Forward.h>
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namespace Gfx {
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// Specified at: https://www.w3.org/Graphics/GIF/spec-gif89a.txt
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class GIFWriter {
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public:
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static ErrorOr<void> encode(Stream&, Bitmap const&);
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};
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}
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