chromium/third_party/blink/renderer/platform/testing/image_decode_to_nia.cc

// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/351564777): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif

// This program converts an image from stdin (e.g. a JPEG, PNG, etc.) to stdout
// (in the NIA/NIE format, a trivial image file format).
//
// The NIA/NIE file format specification is at:
// https://github.com/google/wuffs/blob/master/doc/spec/nie-spec.md
//
// Pass "-1" or "-first-frame-only" as a command line flag to output NIE (a
// still image) instead of NIA (an animated image). The output format (NIA or
// NIE) depends only on this flag's absence or presence, not on the stdin
// image's format.
//
// There are multiple codec implementations of any given image format. For
// example, as of May 2020, Chromium, Skia and Wuffs each have their own BMP
// decoder implementation. There is no standard "libbmp" that they all share.
// Comparing this program's output (or hashed output) to similar programs in
// other repositories can identify image inputs for which these decoders (or
// different versions of the same decoder) produce different output (pixels).
//
// An equivalent program (using the Skia image codecs) is at:
// https://skia-review.googlesource.com/c/skia/+/290618
//
// An equivalent program (using the Wuffs image codecs) is at:
// https://github.com/google/wuffs/blob/master/example/convert-to-nia/convert-to-nia.c

#include <iostream>

#include "base/command_line.h"
#include "base/files/file_util.h"
#include "base/task/single_thread_task_executor.h"
#include "third_party/blink/public/platform/platform.h"
#include "third_party/blink/renderer/platform/image-decoders/image_decoder.h"
#include "third_party/blink/renderer/platform/wtf/shared_buffer.h"
#include "third_party/skia/include/core/SkColor.h"

static inline void set_u32le(uint8_t* ptr, uint32_t val) { … }

static inline void set_u64le(uint8_t* ptr, uint64_t val) { … }

void write_nix_header(uint32_t magic_u32le, uint32_t width, uint32_t height) { … }

bool write_nia_duration(uint64_t total_duration_micros) { … }

void write_nie_pixels(uint32_t width,
                      uint32_t height,
                      blink::ImageFrame* frame) { … }

void write_nia_padding(uint32_t width, uint32_t height) { … }

void write_nia_footer(int repetition_count, size_t frame_count) { … }

int main(int argc, char* argv[]) { … }