blob: 45a25b75251bc2eda46d3d3d5d353f4d2b48cb84 [file] [log] [blame]
// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// This file input format is based loosely on
// Tools/DumpRenderTree/ImageDiff.m
// The exact format of this tool's output to stdout is important, to match
// what the run_web_tests.py script expects.
#include <stddef.h>
#include <stdint.h>
#include <algorithm>
#include <iostream>
#include <memory>
#include <string>
#include <unordered_map>
#include <vector>
#include "base/check.h"
#include "base/command_line.h"
#include "base/files/file_path.h"
#include "base/files/file_util.h"
#include "base/numerics/safe_conversions.h"
#include "base/optional.h"
#include "base/process/memory.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_split.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "build/build_config.h"
#include "tools/imagediff/image_diff_png.h"
#if defined(OS_WIN)
#include "windows.h"
#endif
// Causes the app to remain open, waiting for pairs of filenames on stdin.
// The caller is then responsible for terminating this app.
static const char kOptionPollStdin[] = "use-stdin";
// Causes the app to additionally calculate a diff of the color histograms
// (which is resistant to shifts in layout).
static const char kOptionCompareHistograms[] = "histogram";
// Causes the app to output an image that visualizes the difference.
static const char kOptionGenerateDiff[] = "diff";
// Causes the app to have a tolerance for difference in output. To account for
// differences which occur when running vs hardware GPU output.
static const char kOptionFuzzyDiff[] = "fuzzy-diff";
// Causes the app to use the WPT fuzzy-matching algorithm. Both arguments are
// ranges of the form "x-y", where x and y are integers. If either of these
// arguments are used, both must be.
//
// https://web-platform-tests.org/writing-tests/reftests.html#fuzzy-matching
static const char kOptionFuzzyMaxChannelDiff[] = "fuzzy-max-channel-diff";
static const char kOptionFuzzyMaxPixelsDiff[] = "fuzzy-max-pixels-diff";
// Return codes used by this utility.
static const int kStatusSame = 0;
static const int kStatusDifferent = 1;
static const int kStatusError = 2;
// Color codes.
static const uint32_t RGBA_RED = 0x000000ff;
static const uint32_t RGBA_ALPHA = 0xff000000;
class Image {
public:
Image() : w_(0), h_(0) {
}
Image(const Image& image) = default;
bool has_image() const {
return w_ > 0 && h_ > 0;
}
int w() const {
return w_;
}
int h() const {
return h_;
}
const unsigned char* data() const {
return &data_.front();
}
// Creates the image from stdin with the given data length. On success, it
// will return true. On failure, no other methods should be accessed.
bool CreateFromStdin(size_t byte_length) {
if (byte_length == 0)
return false;
std::unique_ptr<unsigned char[]> source(new unsigned char[byte_length]);
if (fread(source.get(), 1, byte_length, stdin) != byte_length)
return false;
if (!image_diff_png::DecodePNG(source.get(), byte_length,
&data_, &w_, &h_)) {
Clear();
return false;
}
return true;
}
// Creates the image from the given filename on disk, and returns true on
// success.
bool CreateFromFilename(const base::FilePath& path) {
FILE* f = base::OpenFile(path, "rb");
if (!f)
return false;
std::vector<unsigned char> compressed;
const int buf_size = 1024;
unsigned char buf[buf_size];
size_t num_read = 0;
while ((num_read = fread(buf, 1, buf_size, f)) > 0) {
compressed.insert(compressed.end(), buf, buf + num_read);
}
base::CloseFile(f);
if (!image_diff_png::DecodePNG(&compressed[0], compressed.size(),
&data_, &w_, &h_)) {
Clear();
return false;
}
return true;
}
void Clear() {
w_ = h_ = 0;
data_.clear();
}
// Returns the RGBA value of the pixel at the given location
uint32_t pixel_at(int x, int y) const {
DCHECK(x >= 0 && x < w_);
DCHECK(y >= 0 && y < h_);
return *reinterpret_cast<const uint32_t*>(&(data_[(y * w_ + x) * 4]));
}
void set_pixel_at(int x, int y, uint32_t color) const {
DCHECK(x >= 0 && x < w_);
DCHECK(y >= 0 && y < h_);
void* addr = &const_cast<unsigned char*>(&data_.front())[(y * w_ + x) * 4];
*reinterpret_cast<uint32_t*>(addr) = color;
}
private:
// pixel dimensions of the image
int w_, h_;
std::vector<unsigned char> data_;
};
float PercentageDifferent(const Image& baseline,
const Image& actual,
bool fuzzy_diff) {
int w = std::min(baseline.w(), actual.w());
int h = std::min(baseline.h(), actual.h());
// Compute pixels different in the overlap.
int pixels_different = 0;
for (int y = 0; y < h; y++) {
for (int x = 0; x < w; x++) {
if (fuzzy_diff) {
uint32_t pixel_base = baseline.pixel_at(x, y);
uint32_t pixel_actual = actual.pixel_at(x, y);
if (pixel_base == pixel_actual)
continue;
// The pixels are in an rgba format.
uint8_t subpixels_base[4];
uint8_t subpixels_actual[4];
subpixels_base[0] = pixel_base & 0xFF;
subpixels_actual[0] = pixel_actual & 0xFF;
subpixels_base[1] = (pixel_base >> 8) & 0xFF;
subpixels_actual[1] = (pixel_actual >> 8) & 0xFF;
subpixels_base[2] = (pixel_base >> 16) & 0xFF;
subpixels_actual[2] = (pixel_actual >> 16) & 0xFF;
subpixels_base[3] = (pixel_base >> 24) & 0xFF;
subpixels_actual[3] = (pixel_actual >> 24) & 0xFF;
for (int i = 0; i < 4; i++) {
uint8_t subpixel_diff = subpixels_base[i] > subpixels_actual[i]
? subpixels_base[i] - subpixels_actual[i]
: subpixels_actual[i] - subpixels_base[i];
if (subpixel_diff > 1) {
pixels_different++;
break;
}
}
} else if (baseline.pixel_at(x, y) != actual.pixel_at(x, y)) {
pixels_different++;
}
}
}
// Count pixels that are a difference in size as also being different.
int max_w = std::max(baseline.w(), actual.w());
int max_h = std::max(baseline.h(), actual.h());
// These pixels are off the right side, not including the lower right corner.
pixels_different += (max_w - w) * h;
// These pixels are along the bottom, including the lower right corner.
pixels_different += (max_h - h) * max_w;
// Like the WebKit ImageDiff tool, we define percentage different in terms
// of the size of the 'actual' bitmap.
float total_pixels = static_cast<float>(actual.w()) *
static_cast<float>(actual.h());
if (total_pixels == 0) {
// When the bitmap is empty, they are 100% different.
return 100.0f;
}
return 100.0f * pixels_different / total_pixels;
}
typedef std::unordered_map<uint32_t, int32_t> RgbaToCountMap;
float HistogramPercentageDifferent(const Image& baseline, const Image& actual) {
// TODO(johnme): Consider using a joint histogram instead, as described in
// "Comparing Images Using Joint Histograms" by Pass & Zabih
// http://www.cs.cornell.edu/~rdz/papers/pz-jms99.pdf
int w = std::min(baseline.w(), actual.w());
int h = std::min(baseline.h(), actual.h());
// Count occurences of each RGBA pixel value of baseline in the overlap.
RgbaToCountMap baseline_histogram;
for (int y = 0; y < h; y++) {
for (int x = 0; x < w; x++) {
// hash_map operator[] inserts a 0 (default constructor) if key not found.
baseline_histogram[baseline.pixel_at(x, y)]++;
}
}
// Compute pixels different in the histogram of the overlap.
int pixels_different = 0;
for (int y = 0; y < h; y++) {
for (int x = 0; x < w; x++) {
uint32_t actual_rgba = actual.pixel_at(x, y);
RgbaToCountMap::iterator it = baseline_histogram.find(actual_rgba);
if (it != baseline_histogram.end() && it->second > 0)
it->second--;
else
pixels_different++;
}
}
// Count pixels that are a difference in size as also being different.
int max_w = std::max(baseline.w(), actual.w());
int max_h = std::max(baseline.h(), actual.h());
// These pixels are off the right side, not including the lower right corner.
pixels_different += (max_w - w) * h;
// These pixels are along the bottom, including the lower right corner.
pixels_different += (max_h - h) * max_w;
// Like the WebKit ImageDiff tool, we define percentage different in terms
// of the size of the 'actual' bitmap.
float total_pixels = static_cast<float>(actual.w()) *
static_cast<float>(actual.h());
if (total_pixels == 0) {
// When the bitmap is empty, they are 100% different.
return 100.0f;
}
return 100.0f * pixels_different / total_pixels;
}
void PrintHelp() {
fprintf(stderr,
"Usage:\n"
" image_diff [--histogram] <compare file> <reference file>\n"
" Compares two files on disk, returning 0 when they are the same;\n"
" passing \"--histogram\" additionally calculates a diff of the\n"
" RGBA value histograms (which is resistant to shifts in layout)\n"
" image_diff --use-stdin\n"
" Stays open reading pairs of filenames from stdin, comparing them,\n"
" and sending 0 to stdout when they are the same\n"
" image_diff --diff <compare file> <reference file> <output file>\n"
" Compares two files on disk, outputs an image that visualizes the\n"
" difference to <output file>\n");
/* For unfinished webkit-like-mode (see below)
"\n"
" image_diff -s\n"
" Reads stream input from stdin, should be EXACTLY of the format\n"
" \"Content-length: <byte length> <data>Content-length: ...\n"
" it will take as many file pairs as given, and will compare them as\n"
" (cmp_file, reference_file) pairs\n");
*/
}
int CompareImages(const base::FilePath& file1,
const base::FilePath& file2,
bool compare_histograms,
bool fuzzy_diff) {
Image actual_image;
Image baseline_image;
if (!actual_image.CreateFromFilename(file1)) {
fprintf(stderr, "image_diff: Unable to open file \"%" PRFilePath "\"\n",
file1.value().c_str());
return kStatusError;
}
if (!baseline_image.CreateFromFilename(file2)) {
fprintf(stderr, "image_diff: Unable to open file \"%" PRFilePath "\"\n",
file2.value().c_str());
return kStatusError;
}
float tolerance = fuzzy_diff ? 1.0f : 0.0f;
if (compare_histograms) {
float percent = HistogramPercentageDifferent(actual_image, baseline_image);
const char* passed = percent > tolerance ? "failed" : "passed";
printf("histogram diff: %01.2f%% %s\n", percent, passed);
}
const char* diff_name = compare_histograms ? "exact diff" : "diff";
float percent = PercentageDifferent(actual_image, baseline_image, fuzzy_diff);
const char* passed = percent > tolerance ? "failed" : "passed";
printf("%s: %01.2f%% %s\n", diff_name, percent, passed);
if (percent > tolerance) {
// failure: The WebKit version also writes the difference image to
// stdout, which seems excessive for our needs.
return kStatusDifferent;
}
// success
return kStatusSame;
/* Untested mode that acts like WebKit's image comparator. I wrote this but
decided it's too complicated. We may use it in the future if it looks useful
char buffer[2048];
while (fgets(buffer, sizeof(buffer), stdin)) {
if (strncmp("Content-length: ", buffer, 16) == 0) {
char* context;
strtok_s(buffer, " ", &context);
int image_size = strtol(strtok_s(NULL, " ", &context), NULL, 10);
bool success = false;
if (image_size > 0 && actual_image.has_image() == 0) {
if (!actual_image.CreateFromStdin(image_size)) {
fputs("Error, input image can't be decoded.\n", stderr);
return 1;
}
} else if (image_size > 0 && baseline_image.has_image() == 0) {
if (!baseline_image.CreateFromStdin(image_size)) {
fputs("Error, baseline image can't be decoded.\n", stderr);
return 1;
}
} else {
fputs("Error, image size must be specified.\n", stderr);
return 1;
}
}
if (actual_image.has_image() && baseline_image.has_image()) {
float percent = PercentageDifferent(actual_image, baseline_image);
if (percent > 0.0) {
// failure: The WebKit version also writes the difference image to
// stdout, which seems excessive for our needs.
printf("diff: %01.2f%% failed\n", percent);
} else {
// success
printf("diff: %01.2f%% passed\n", percent);
}
actual_image.Clear();
baseline_image.Clear();
}
fflush(stdout);
}
*/
}
// Calculate the absolute difference between two pixels in a specified channel
// c, assuming the pixels are encoded with four 8-bit channels.
uint8_t GetChannelDiff(int c, uint32_t base_pixel, uint32_t actual_pixel) {
int shift = c * 8;
uint8_t channel_base = (base_pixel >> shift) & 0xFF;
uint8_t channel_actual = (actual_pixel >> shift) & 0xFF;
return channel_base > channel_actual ? channel_base - channel_actual
: channel_actual - channel_base;
}
bool CreateImageDiff(const Image& image1,
const Image& image2,
bool fuzzy_diff,
std::vector<int> fuzzy_allowed_max_channel_diff,
std::vector<int> fuzzy_allowed_pixels_diff,
Image* out) {
int w = std::min(image1.w(), image2.w());
int h = std::min(image1.h(), image2.h());
*out = Image(image1);
bool same = (image1.w() == image2.w()) && (image1.h() == image2.h());
// TODO(estade): do something with the extra pixels if the image sizes
// are different.
int pixels_different = 0;
uint8_t max_channel_diff = 0;
for (int y = 0; y < h; y++) {
for (int x = 0; x < w; x++) {
uint32_t base_pixel = image1.pixel_at(x, y);
uint32_t actual_pixel = image2.pixel_at(x, y);
if (base_pixel != actual_pixel) {
// Set differing pixels red.
out->set_pixel_at(x, y, RGBA_RED | RGBA_ALPHA);
same = false;
// Record the necessary information for WPT fuzzy matching. WPT images
// only compare on the RGB channels, not A.
pixels_different++;
for (int c = 0; c < 3; c++) {
max_channel_diff = std::max(
max_channel_diff, GetChannelDiff(c, base_pixel, actual_pixel));
}
} else {
// Set same pixels as faded.
uint32_t alpha = base_pixel & RGBA_ALPHA;
uint32_t new_pixel = base_pixel - ((alpha / 2) & RGBA_ALPHA);
out->set_pixel_at(x, y, new_pixel);
}
}
}
if (!same) {
printf("Found pixels_different: %d, max_channel_diff: %u\n",
pixels_different, max_channel_diff);
}
if (!fuzzy_diff) {
return same;
}
if (fuzzy_allowed_max_channel_diff.empty()) {
float percent = PercentageDifferent(image1, image2, fuzzy_diff);
return percent < 1.0f;
}
// WPT fuzzy matching. This algorithm is equivalent to 'check_pass' in
// tools/wptrunner/wptrunner/executors/base.py
printf("Allowed pixels_different; %d-%d, max_channel_diff: %u-%u\n",
fuzzy_allowed_pixels_diff[0], fuzzy_allowed_pixels_diff[1],
fuzzy_allowed_max_channel_diff[0], fuzzy_allowed_max_channel_diff[1]);
return ((pixels_different == 0 && fuzzy_allowed_pixels_diff[0] == 0) ||
(max_channel_diff == 0 && fuzzy_allowed_max_channel_diff[0] == 0) ||
(fuzzy_allowed_pixels_diff[0] <= pixels_different &&
pixels_different <= fuzzy_allowed_pixels_diff[1] &&
fuzzy_allowed_max_channel_diff[0] <= max_channel_diff &&
max_channel_diff <= fuzzy_allowed_max_channel_diff[1]));
}
int DiffImages(const base::FilePath& file1,
const base::FilePath& file2,
bool fuzzy_diff,
std::vector<int> max_per_channel,
std::vector<int> max_pixels_different,
const base::FilePath& out_file) {
Image actual_image;
Image baseline_image;
if (!actual_image.CreateFromFilename(file1)) {
fprintf(stderr, "image_diff: Unable to open file \"%" PRFilePath "\"\n",
file1.value().c_str());
return kStatusError;
}
if (!baseline_image.CreateFromFilename(file2)) {
fprintf(stderr, "image_diff: Unable to open file \"%" PRFilePath "\"\n",
file2.value().c_str());
return kStatusError;
}
Image diff_image;
bool same =
CreateImageDiff(baseline_image, actual_image, fuzzy_diff, max_per_channel,
max_pixels_different, &diff_image);
if (same)
return kStatusSame;
std::vector<unsigned char> png_encoding;
image_diff_png::EncodeRGBAPNG(
diff_image.data(), diff_image.w(), diff_image.h(),
diff_image.w() * 4, &png_encoding);
if (base::WriteFile(out_file,
reinterpret_cast<char*>(&png_encoding.front()),
base::checked_cast<int>(png_encoding.size())) < 0)
return kStatusError;
return kStatusDifferent;
}
// It isn't strictly correct to only support ASCII paths, but this
// program reads paths on stdin and the program that spawns it outputs
// paths as non-wide strings anyway.
base::FilePath FilePathFromASCII(const std::string& str) {
#if defined(OS_WIN)
return base::FilePath(base::ASCIIToUTF16(str));
#else
return base::FilePath(str);
#endif
}
// Parses a range command line option of the form "x-y", where x and y are both
// integers. If the range cannot be parsed, returns kStatusError.
int ParseRangeOption(const std::string& range, std::vector<int>& parsed_range) {
if (range.empty())
return 0;
std::vector<std::string> tokens = base::SplitString(
range, "-", base::KEEP_WHITESPACE, base::SPLIT_WANT_ALL);
if (tokens.size() != 2) {
fprintf(stderr, "Unable to parse range: '%s'\n", range.c_str());
return kStatusError;
}
int min, max;
if (!base::StringToInt(tokens[0], &min) ||
!base::StringToInt(tokens[1], &max)) {
fprintf(stderr, "Unable to parse range: '%s'\n", range.c_str());
return kStatusError;
}
parsed_range.push_back(min);
parsed_range.push_back(max);
return 0;
}
int main(int argc, const char* argv[]) {
base::EnableTerminationOnHeapCorruption();
base::CommandLine::Init(argc, argv);
const base::CommandLine& parsed_command_line =
*base::CommandLine::ForCurrentProcess();
bool fuzzy_diff = parsed_command_line.HasSwitch(kOptionFuzzyDiff);
bool histograms = parsed_command_line.HasSwitch(kOptionCompareHistograms);
std::vector<int> fuzzy_max_channel_diff;
if (ParseRangeOption(
parsed_command_line.GetSwitchValueASCII(kOptionFuzzyMaxChannelDiff),
fuzzy_max_channel_diff) == kStatusError) {
return kStatusError;
}
std::vector<int> fuzzy_max_pixels_diff;
if (ParseRangeOption(
parsed_command_line.GetSwitchValueASCII(kOptionFuzzyMaxPixelsDiff),
fuzzy_max_pixels_diff) == kStatusError) {
return kStatusError;
}
// If using either of the WPT fuzzy options, both must be supplied.
if (fuzzy_max_channel_diff.size() != fuzzy_max_pixels_diff.size()) {
fprintf(
stderr,
"Either both --%s and --%s must be specified, or neither should be.\n",
kOptionFuzzyMaxChannelDiff, kOptionFuzzyMaxPixelsDiff);
return kStatusError;
} else if (!fuzzy_max_channel_diff.empty()) {
// The WPT fuzzy options imply a fuzzy diff is happening.
fuzzy_diff = true;
}
if (parsed_command_line.HasSwitch(kOptionPollStdin)) {
// Watch stdin for filenames.
std::string stdin_buffer;
base::FilePath filename1;
while (std::getline(std::cin, stdin_buffer)) {
if (stdin_buffer.empty())
continue;
if (!filename1.empty()) {
// CompareImages writes results to stdout unless an error occurred.
base::FilePath filename2 = FilePathFromASCII(stdin_buffer);
if (CompareImages(filename1, filename2, histograms, fuzzy_diff) ==
kStatusError) {
printf("error\n");
}
fflush(stdout);
filename1 = base::FilePath();
} else {
// Save the first filename in another buffer and wait for the second
// filename to arrive via stdin.
filename1 = FilePathFromASCII(stdin_buffer);
}
}
return 0;
}
const base::CommandLine::StringVector& args = parsed_command_line.GetArgs();
if (parsed_command_line.HasSwitch(kOptionGenerateDiff)) {
if (args.size() == 3) {
return DiffImages(base::FilePath(args[0]), base::FilePath(args[1]),
fuzzy_diff, fuzzy_max_channel_diff,
fuzzy_max_pixels_diff, base::FilePath(args[2]));
}
} else if (args.size() == 2) {
return CompareImages(base::FilePath(args[0]), base::FilePath(args[1]),
fuzzy_diff, histograms);
}
PrintHelp();
return kStatusError;
}