mirror of
https://github.com/LadybirdBrowser/ladybird.git
synced 2024-09-29 16:21:29 +00:00
LibGfx/WebPWriter: Move VP8L compression to WebPWriterLossless.{h,cpp}
* Matches how the loader is organized * `compress_VP8L_image_data()` will grow longer when we add actual compression * Maybe someone wants to write a lossy compressor one day No behavior change.
This commit is contained in:
parent
c0f67a0188
commit
b6bbff5f3f
Notes:
sideshowbarker
2024-07-17 01:11:48 +09:00
Author: https://github.com/nico Commit: https://github.com/SerenityOS/serenity/commit/b6bbff5f3f Pull-request: https://github.com/SerenityOS/serenity/pull/24332
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@ -98,6 +98,7 @@ shared_library("LibGfx") {
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"ImageFormats/WebPLoaderLossless.cpp",
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"ImageFormats/WebPLoaderLossy.cpp",
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"ImageFormats/WebPWriter.cpp",
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"ImageFormats/WebPWriterLossless.cpp",
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"ImmutableBitmap.cpp",
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"Painter.cpp",
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"Palette.cpp",
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@ -72,6 +72,7 @@ set(SOURCES
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ImageFormats/WebPLoaderLossless.cpp
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ImageFormats/WebPLoaderLossy.cpp
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ImageFormats/WebPWriter.cpp
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ImageFormats/WebPWriterLossless.cpp
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ImmutableBitmap.cpp
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Painter.cpp
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Palette.cpp
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@ -5,16 +5,16 @@
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*/
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// Container: https://developers.google.com/speed/webp/docs/riff_container
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// Lossless format: https://developers.google.com/speed/webp/docs/webp_lossless_bitstream_specification
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#include <AK/BitStream.h>
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#include <AK/Debug.h>
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#include <LibCompress/DeflateTables.h>
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#include <AK/Endian.h>
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#include <AK/MemoryStream.h>
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#include <LibGfx/Bitmap.h>
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#include <LibGfx/ImageFormats/AnimationWriter.h>
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#include <LibGfx/ImageFormats/WebPShared.h>
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#include <LibGfx/ImageFormats/WebPWriter.h>
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#include <LibRIFF/RIFF.h>
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#include <LibGfx/ImageFormats/WebPWriterLossless.h>
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namespace Gfx {
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@ -76,128 +76,6 @@ static bool are_all_pixels_opaque(Bitmap const& bitmap)
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return true;
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}
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static ErrorOr<void> write_VP8L_image_data(Stream& stream, Bitmap const& bitmap)
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{
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LittleEndianOutputBitStream bit_stream { MaybeOwned<Stream>(stream) };
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// optional-transform = (%b1 transform optional-transform) / %b0
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TRY(bit_stream.write_bits(0u, 1u)); // No transform for now.
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// https://developers.google.com/speed/webp/docs/webp_lossless_bitstream_specification#5_image_data
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// spatially-coded-image = color-cache-info meta-prefix data
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// color-cache-info = %b0
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// color-cache-info =/ (%b1 4BIT) ; 1 followed by color cache size
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TRY(bit_stream.write_bits(0u, 1u)); // No color cache for now.
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// meta-prefix = %b0 / (%b1 entropy-image)
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TRY(bit_stream.write_bits(0u, 1u)); // No meta prefix for now.
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// data = prefix-codes lz77-coded-image
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// prefix-codes = prefix-code-group *prefix-codes
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// prefix-code-group =
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// 5prefix-code ; See "Interpretation of Meta Prefix Codes" to
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// ; understand what each of these five prefix
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// ; codes are for.
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// We're writing a single prefix-code-group.
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// "These codes are (in bitstream order):
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// Prefix code #1: Used for green channel, backward-reference length, and color cache.
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// Prefix code #2, #3, and #4: Used for red, blue, and alpha channels, respectively.
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// Prefix code #5: Used for backward-reference distance."
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// We use neither back-references not color cache entries yet.
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// We write prefix trees for 256 literals all of length 8, which means each byte is encoded as itself.
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// That doesn't give any compression, but is a valid bit stream.
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// We can make this smarter later on.
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size_t const color_cache_size = 0;
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constexpr Array alphabet_sizes = to_array<size_t>({ 256 + 24 + static_cast<size_t>(color_cache_size), 256, 256, 256, 40 }); // XXX Shared?
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// If you add support for color cache: At the moment, CanonicalCodes does not support writing more than 288 symbols.
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if (alphabet_sizes[0] > 288)
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return Error::from_string_literal("Invalid alphabet size");
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bool all_pixels_are_opaque = are_all_pixels_opaque(bitmap);
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int number_of_full_channels = all_pixels_are_opaque ? 3 : 4;
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for (int i = 0; i < number_of_full_channels; ++i) {
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TRY(bit_stream.write_bits(0u, 1u)); // Normal code length code.
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// Write code length codes.
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constexpr int kCodeLengthCodes = 19;
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Array<int, kCodeLengthCodes> kCodeLengthCodeOrder = { 17, 18, 0, 1, 2, 3, 4, 5, 16, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 };
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int num_code_lengths = max(4u, find_index(kCodeLengthCodeOrder.begin(), kCodeLengthCodeOrder.end(), 8) + 1);
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// "int num_code_lengths = 4 + ReadBits(4);"
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TRY(bit_stream.write_bits(num_code_lengths - 4u, 4u));
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for (int i = 0; i < num_code_lengths - 1; ++i)
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TRY(bit_stream.write_bits(0u, 3u));
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TRY(bit_stream.write_bits(1u, 3u));
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// Write code lengths.
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if (alphabet_sizes[i] == 256) {
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TRY(bit_stream.write_bits(0u, 1u)); // max_symbol is alphabet_size
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} else {
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TRY(bit_stream.write_bits(1u, 1u)); // max_symbol is explicitly coded
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// "int length_nbits = 2 + 2 * ReadBits(3);
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// int max_symbol = 2 + ReadBits(length_nbits);"
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TRY(bit_stream.write_bits(3u, 3u)); // length_nbits = 2 + 2 * 3
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TRY(bit_stream.write_bits(254u, 8u)); // max_symbol = 2 + 254
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}
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// The code length codes only contain a single entry for '8'. WebP streams with a single element store 0 bits per element.
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// (This is different from deflate, which needs 1 bit per element.)
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}
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if (all_pixels_are_opaque) {
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// Use a simple 1-element code.
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TRY(bit_stream.write_bits(1u, 1u)); // Simple code length code.
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TRY(bit_stream.write_bits(0u, 1u)); // num_symbols - 1
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TRY(bit_stream.write_bits(1u, 1u)); // is_first_8bits
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TRY(bit_stream.write_bits(255u, 8u)); // symbol0
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}
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// For code #5, use a simple empty code, since we don't use this yet.
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TRY(bit_stream.write_bits(1u, 1u)); // Simple code length code.
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TRY(bit_stream.write_bits(0u, 1u)); // num_symbols - 1
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TRY(bit_stream.write_bits(0u, 1u)); // is_first_8bits
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TRY(bit_stream.write_bits(0u, 1u)); // symbol0
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// Image data.
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for (ARGB32 pixel : bitmap) {
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u8 a = pixel >> 24;
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u8 r = pixel >> 16;
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u8 g = pixel >> 8;
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u8 b = pixel;
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// We wrote a huffman table that gives every symbol 8 bits. That means we can write the image data
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// out uncompressed –- but we do need to reverse the bit order of the bytes.
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TRY(bit_stream.write_bits(Compress::reverse8_lookup_table[g], 8u));
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TRY(bit_stream.write_bits(Compress::reverse8_lookup_table[r], 8u));
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TRY(bit_stream.write_bits(Compress::reverse8_lookup_table[b], 8u));
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// If all pixels are opaque, we wrote a one-element huffman table for alpha, which needs 0 bits per element.
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if (!all_pixels_are_opaque)
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TRY(bit_stream.write_bits(Compress::reverse8_lookup_table[a], 8u));
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}
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// FIXME: Make ~LittleEndianOutputBitStream do this, or make it VERIFY() that it has happened at least.
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TRY(bit_stream.align_to_byte_boundary());
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TRY(bit_stream.flush_buffer_to_stream());
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return {};
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}
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static ErrorOr<ByteBuffer> compress_VP8L_image_data(Bitmap const& bitmap)
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{
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AllocatingMemoryStream vp8l_data_stream;
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TRY(write_VP8L_image_data(vp8l_data_stream, bitmap));
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return vp8l_data_stream.read_until_eof();
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}
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// FIXME: Consider using LibRIFF for RIFF writing details. (It currently has no writing support.)
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static ErrorOr<void> align_to_two(Stream& stream, size_t number_of_bytes_written)
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{
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150
Userland/Libraries/LibGfx/ImageFormats/WebPWriterLossless.cpp
Normal file
150
Userland/Libraries/LibGfx/ImageFormats/WebPWriterLossless.cpp
Normal file
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@ -0,0 +1,150 @@
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/*
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* Copyright (c) 2024, Nico Weber <thakis@chromium.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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// Lossless format: https://developers.google.com/speed/webp/docs/webp_lossless_bitstream_specification
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#include <AK/BitStream.h>
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#include <AK/Debug.h>
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#include <AK/Endian.h>
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#include <AK/MemoryStream.h>
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#include <LibCompress/DeflateTables.h>
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#include <LibGfx/Bitmap.h>
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#include <LibGfx/ImageFormats/WebPWriterLossless.h>
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namespace Gfx {
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static bool are_all_pixels_opaque(Bitmap const& bitmap)
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{
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for (ARGB32 pixel : bitmap) {
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if ((pixel >> 24) != 0xff)
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return false;
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}
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return true;
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}
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static ErrorOr<void> write_VP8L_image_data(Stream& stream, Bitmap const& bitmap)
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{
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LittleEndianOutputBitStream bit_stream { MaybeOwned<Stream>(stream) };
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// optional-transform = (%b1 transform optional-transform) / %b0
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TRY(bit_stream.write_bits(0u, 1u)); // No transform for now.
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// https://developers.google.com/speed/webp/docs/webp_lossless_bitstream_specification#5_image_data
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// spatially-coded-image = color-cache-info meta-prefix data
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// color-cache-info = %b0
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// color-cache-info =/ (%b1 4BIT) ; 1 followed by color cache size
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TRY(bit_stream.write_bits(0u, 1u)); // No color cache for now.
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// meta-prefix = %b0 / (%b1 entropy-image)
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TRY(bit_stream.write_bits(0u, 1u)); // No meta prefix for now.
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// data = prefix-codes lz77-coded-image
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// prefix-codes = prefix-code-group *prefix-codes
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// prefix-code-group =
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// 5prefix-code ; See "Interpretation of Meta Prefix Codes" to
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// ; understand what each of these five prefix
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// ; codes are for.
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// We're writing a single prefix-code-group.
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// "These codes are (in bitstream order):
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// Prefix code #1: Used for green channel, backward-reference length, and color cache.
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// Prefix code #2, #3, and #4: Used for red, blue, and alpha channels, respectively.
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// Prefix code #5: Used for backward-reference distance."
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// We use neither back-references not color cache entries yet.
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// We write prefix trees for 256 literals all of length 8, which means each byte is encoded as itself.
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// That doesn't give any compression, but is a valid bit stream.
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// We can make this smarter later on.
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size_t const color_cache_size = 0;
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constexpr Array alphabet_sizes = to_array<size_t>({ 256 + 24 + static_cast<size_t>(color_cache_size), 256, 256, 256, 40 }); // XXX Shared?
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// If you add support for color cache: At the moment, CanonicalCodes does not support writing more than 288 symbols.
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if (alphabet_sizes[0] > 288)
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return Error::from_string_literal("Invalid alphabet size");
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bool all_pixels_are_opaque = are_all_pixels_opaque(bitmap);
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int number_of_full_channels = all_pixels_are_opaque ? 3 : 4;
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for (int i = 0; i < number_of_full_channels; ++i) {
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TRY(bit_stream.write_bits(0u, 1u)); // Normal code length code.
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// Write code length codes.
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constexpr int kCodeLengthCodes = 19;
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Array<int, kCodeLengthCodes> kCodeLengthCodeOrder = { 17, 18, 0, 1, 2, 3, 4, 5, 16, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 };
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int num_code_lengths = max(4u, find_index(kCodeLengthCodeOrder.begin(), kCodeLengthCodeOrder.end(), 8) + 1);
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// "int num_code_lengths = 4 + ReadBits(4);"
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TRY(bit_stream.write_bits(num_code_lengths - 4u, 4u));
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for (int i = 0; i < num_code_lengths - 1; ++i)
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TRY(bit_stream.write_bits(0u, 3u));
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TRY(bit_stream.write_bits(1u, 3u));
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// Write code lengths.
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if (alphabet_sizes[i] == 256) {
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TRY(bit_stream.write_bits(0u, 1u)); // max_symbol is alphabet_size
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} else {
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TRY(bit_stream.write_bits(1u, 1u)); // max_symbol is explicitly coded
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// "int length_nbits = 2 + 2 * ReadBits(3);
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// int max_symbol = 2 + ReadBits(length_nbits);"
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TRY(bit_stream.write_bits(3u, 3u)); // length_nbits = 2 + 2 * 3
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TRY(bit_stream.write_bits(254u, 8u)); // max_symbol = 2 + 254
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}
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// The code length codes only contain a single entry for '8'. WebP streams with a single element store 0 bits per element.
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// (This is different from deflate, which needs 1 bit per element.)
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}
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if (all_pixels_are_opaque) {
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// Use a simple 1-element code.
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TRY(bit_stream.write_bits(1u, 1u)); // Simple code length code.
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TRY(bit_stream.write_bits(0u, 1u)); // num_symbols - 1
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TRY(bit_stream.write_bits(1u, 1u)); // is_first_8bits
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TRY(bit_stream.write_bits(255u, 8u)); // symbol0
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}
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// For code #5, use a simple empty code, since we don't use this yet.
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TRY(bit_stream.write_bits(1u, 1u)); // Simple code length code.
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TRY(bit_stream.write_bits(0u, 1u)); // num_symbols - 1
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TRY(bit_stream.write_bits(0u, 1u)); // is_first_8bits
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TRY(bit_stream.write_bits(0u, 1u)); // symbol0
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// Image data.
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for (ARGB32 pixel : bitmap) {
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u8 a = pixel >> 24;
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u8 r = pixel >> 16;
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u8 g = pixel >> 8;
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u8 b = pixel;
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// We wrote a huffman table that gives every symbol 8 bits. That means we can write the image data
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// out uncompressed –- but we do need to reverse the bit order of the bytes.
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TRY(bit_stream.write_bits(Compress::reverse8_lookup_table[g], 8u));
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TRY(bit_stream.write_bits(Compress::reverse8_lookup_table[r], 8u));
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TRY(bit_stream.write_bits(Compress::reverse8_lookup_table[b], 8u));
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// If all pixels are opaque, we wrote a one-element huffman table for alpha, which needs 0 bits per element.
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if (!all_pixels_are_opaque)
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TRY(bit_stream.write_bits(Compress::reverse8_lookup_table[a], 8u));
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}
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// FIXME: Make ~LittleEndianOutputBitStream do this, or make it VERIFY() that it has happened at least.
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TRY(bit_stream.align_to_byte_boundary());
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TRY(bit_stream.flush_buffer_to_stream());
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return {};
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}
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ErrorOr<ByteBuffer> compress_VP8L_image_data(Bitmap const& bitmap)
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{
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AllocatingMemoryStream vp8l_data_stream;
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TRY(write_VP8L_image_data(vp8l_data_stream, bitmap));
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return vp8l_data_stream.read_until_eof();
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}
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}
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16
Userland/Libraries/LibGfx/ImageFormats/WebPWriterLossless.h
Normal file
16
Userland/Libraries/LibGfx/ImageFormats/WebPWriterLossless.h
Normal file
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@ -0,0 +1,16 @@
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/*
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* Copyright (c) 2024, Nico Weber <thakis@chromium.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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ErrorOr<ByteBuffer> compress_VP8L_image_data(Bitmap const&);
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}
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