diff options
Diffstat (limited to 'testing/image_diff')
| -rw-r--r-- | testing/image_diff/DEPS | 5 | ||||
| -rw-r--r-- | testing/image_diff/image_diff.cpp | 336 | ||||
| -rw-r--r-- | testing/image_diff/image_diff_png.cpp | 660 | ||||
| -rw-r--r-- | testing/image_diff/image_diff_png.h | 38 |
4 files changed, 1039 insertions, 0 deletions
diff --git a/testing/image_diff/DEPS b/testing/image_diff/DEPS new file mode 100644 index 0000000000..4bd2335cd7 --- /dev/null +++ b/testing/image_diff/DEPS @@ -0,0 +1,5 @@ +include_rules = [ + '+third_party/libpng16', + '+third_party/zlib', +] + diff --git a/testing/image_diff/image_diff.cpp b/testing/image_diff/image_diff.cpp new file mode 100644 index 0000000000..806e0c84d5 --- /dev/null +++ b/testing/image_diff/image_diff.cpp @@ -0,0 +1,336 @@ +// 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-webkit-tests script expects. + +#include <assert.h> +#include <stdint.h> +#include <stdio.h> +#include <string.h> + +#include <algorithm> +#include <iostream> +#include <map> +#include <string> +#include <vector> + +#include "core/fxcrt/fx_memory.h" +#include "testing/image_diff/image_diff_png.h" +#include "third_party/base/logging.h" +#include "third_party/base/numerics/safe_conversions.h" + +#if defined(OS_WIN) +#include <windows.h> +#endif + +// 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) : w_(image.w_), h_(image.h_), data_(image.data_) {} + + 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 the given filename on disk, and returns true on + // success. + bool CreateFromFilename(const std::string& path) { + FILE* f = fopen(path.c_str(), "rb"); + if (!f) + return false; + + std::vector<unsigned char> compressed; + const size_t kBufSize = 1024; + unsigned char buf[kBufSize]; + size_t num_read = 0; + while ((num_read = fread(buf, 1, kBufSize, f)) > 0) { + compressed.insert(compressed.end(), buf, buf + num_read); + } + + fclose(f); + + if (!image_diff_png::DecodePNG(compressed.data(), 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 { + if (!pixel_in_bounds(x, y)) + return 0; + return *reinterpret_cast<const uint32_t*>(&(data_[pixel_address(x, y)])); + } + + void set_pixel_at(int x, int y, uint32_t color) { + if (!pixel_in_bounds(x, y)) + return; + + void* addr = &data_[pixel_address(x, y)]; + *reinterpret_cast<uint32_t*>(addr) = color; + } + + private: + bool pixel_in_bounds(int x, int y) const { + return x >= 0 && x < w_ && y >= 0 && y < h_; + } + + size_t pixel_address(int x, int y) const { return (y * w_ + x) * 4; } + + // Pixel dimensions of the image. + int w_; + int h_; + + std::vector<unsigned char> data_; +}; + +float CalculateDifferencePercentage(const Image& actual, int pixels_different) { + // 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 CountImageSizeMismatchAsPixelDifference(const Image& baseline, + const Image& actual, + int* pixels_different) { + int w = std::min(baseline.w(), actual.w()); + int h = std::min(baseline.h(), actual.h()); + + // 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; +} + +float PercentageDifferent(const Image& baseline, const Image& actual) { + 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 (baseline.pixel_at(x, y) != actual.pixel_at(x, y)) + ++pixels_different; + } + } + + CountImageSizeMismatchAsPixelDifference(baseline, actual, &pixels_different); + return CalculateDifferencePercentage(actual, pixels_different); +} + +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. + std::map<uint32_t, int32_t> 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); + auto it = baseline_histogram.find(actual_rgba); + if (it != baseline_histogram.end() && it->second > 0) + --it->second; + else + ++pixels_different; + } + } + + CountImageSizeMismatchAsPixelDifference(baseline, actual, &pixels_different); + return CalculateDifferencePercentage(actual, pixels_different); +} + +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 --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"); +} + +int CompareImages(const std::string& file1, + const std::string& file2, + bool compare_histograms) { + Image actual_image; + Image baseline_image; + + if (!actual_image.CreateFromFilename(file1)) { + fprintf(stderr, "image_diff: Unable to open file \"%s\"\n", file1.c_str()); + return kStatusError; + } + if (!baseline_image.CreateFromFilename(file2)) { + fprintf(stderr, "image_diff: Unable to open file \"%s\"\n", file2.c_str()); + return kStatusError; + } + + if (compare_histograms) { + float percent = HistogramPercentageDifferent(actual_image, baseline_image); + const char* passed = percent > 0.0 ? "failed" : "passed"; + printf("histogram diff: %01.2f%% %s\n", percent, passed); + } + + const char* const diff_name = compare_histograms ? "exact diff" : "diff"; + float percent = PercentageDifferent(actual_image, baseline_image); + const char* const passed = percent > 0.0 ? "failed" : "passed"; + printf("%s: %01.2f%% %s\n", diff_name, percent, passed); + + if (percent > 0.0) { + // failure: The WebKit version also writes the difference image to + // stdout, which seems excessive for our needs. + return kStatusDifferent; + } + // success + return kStatusSame; +} + +bool CreateImageDiff(const Image& image1, const Image& image2, 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. + for (int y = 0; y < h; ++y) { + for (int x = 0; x < w; ++x) { + uint32_t base_pixel = image1.pixel_at(x, y); + if (base_pixel != image2.pixel_at(x, y)) { + // Set differing pixels red. + out->set_pixel_at(x, y, RGBA_RED | RGBA_ALPHA); + same = false; + } 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); + } + } + } + + return same; +} + +int DiffImages(const std::string& file1, + const std::string& file2, + const std::string& out_file) { + Image actual_image; + Image baseline_image; + + if (!actual_image.CreateFromFilename(file1)) { + fprintf(stderr, "image_diff: Unable to open file \"%s\"\n", file1.c_str()); + return kStatusError; + } + if (!baseline_image.CreateFromFilename(file2)) { + fprintf(stderr, "image_diff: Unable to open file \"%s\"\n", file2.c_str()); + return kStatusError; + } + + Image diff_image; + bool same = CreateImageDiff(baseline_image, actual_image, &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); + + FILE* f = fopen(out_file.c_str(), "wb"); + if (!f) + return kStatusError; + + size_t size = png_encoding.size(); + char* ptr = reinterpret_cast<char*>(&png_encoding.front()); + if (fwrite(ptr, 1, size, f) != size) + return kStatusError; + + return kStatusDifferent; +} + +int main(int argc, const char* argv[]) { + FXMEM_InitializePartitionAlloc(); + + bool histograms = false; + bool produce_diff_image = false; + std::string filename1; + std::string filename2; + std::string diff_filename; + + int i; + for (i = 1; i < argc; ++i) { + const char* arg = argv[i]; + if (strstr(arg, "--") != arg) + break; + if (strcmp(arg, "--histogram") == 0) { + histograms = true; + } else if (strcmp(arg, "--diff") == 0) { + produce_diff_image = true; + } + } + if (i < argc) + filename1 = argv[i++]; + if (i < argc) + filename2 = argv[i++]; + if (i < argc) + diff_filename = argv[i++]; + + if (produce_diff_image) { + if (!diff_filename.empty()) { + return DiffImages(filename1, filename2, diff_filename); + } + } else if (!filename2.empty()) { + return CompareImages(filename1, filename2, histograms); + } + + PrintHelp(); + return kStatusError; +} diff --git a/testing/image_diff/image_diff_png.cpp b/testing/image_diff/image_diff_png.cpp new file mode 100644 index 0000000000..a5e8cdb101 --- /dev/null +++ b/testing/image_diff/image_diff_png.cpp @@ -0,0 +1,660 @@ +// Copyright 2013 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 is a duplicate of chromium's src/tools/imagediff/image_diff_png.cc +// that has been modified to build in a pdfium environment, which itself +// was duplicated as follows: + +// This is a duplicate of ui/gfx/codec/png_codec.cc, after removing code related +// to Skia, that we can use when running layout tests with minimal dependencies. + +#include "testing/image_diff/image_diff_png.h" + +#include <stdlib.h> +#include <string.h> + +#include <string> + +#include "third_party/base/logging.h" +#include "third_party/libpng16/png.h" +#include "third_party/zlib/zlib.h" + +namespace image_diff_png { + +namespace { + +enum ColorFormat { + // 3 bytes per pixel (packed), in RGB order regardless of endianness. + // This is the native JPEG format. + FORMAT_RGB, + + // 4 bytes per pixel, in RGBA order in memory regardless of endianness. + FORMAT_RGBA, + + // 4 bytes per pixel, in BGRA order in memory regardless of endianness. + // This is the default Windows DIB order. + FORMAT_BGRA, +}; + +// Represents a comment in the tEXt ancillary chunk of the png. +struct Comment { + std::string key; + std::string text; +}; + +// Converts BGRA->RGBA and RGBA->BGRA. +void ConvertBetweenBGRAandRGBA(const unsigned char* input, + int pixel_width, + unsigned char* output, + bool* is_opaque) { + for (int x = 0; x < pixel_width; x++) { + const unsigned char* pixel_in = &input[x * 4]; + unsigned char* pixel_out = &output[x * 4]; + pixel_out[0] = pixel_in[2]; + pixel_out[1] = pixel_in[1]; + pixel_out[2] = pixel_in[0]; + pixel_out[3] = pixel_in[3]; + } +} + +void ConvertRGBAtoRGB(const unsigned char* rgba, + int pixel_width, + unsigned char* rgb, + bool* is_opaque) { + for (int x = 0; x < pixel_width; x++) { + const unsigned char* pixel_in = &rgba[x * 4]; + unsigned char* pixel_out = &rgb[x * 3]; + pixel_out[0] = pixel_in[0]; + pixel_out[1] = pixel_in[1]; + pixel_out[2] = pixel_in[2]; + } +} + +} // namespace + +// Decoder +// +// This code is based on WebKit libpng interface (PNGImageDecoder), which is +// in turn based on the Mozilla png decoder. + +namespace { + +// Gamma constants: We assume we're on Windows which uses a gamma of 2.2. +const double kMaxGamma = 21474.83; // Maximum gamma accepted by png library. +const double kDefaultGamma = 2.2; +const double kInverseGamma = 1.0 / kDefaultGamma; + +class PngDecoderState { + public: + // Output is a vector<unsigned char>. + PngDecoderState(ColorFormat ofmt, std::vector<unsigned char>* o) + : output_format(ofmt), + output_channels(0), + is_opaque(true), + output(o), + row_converter(NULL), + width(0), + height(0), + done(false) {} + + ColorFormat output_format; + int output_channels; + + // Used during the reading of an SkBitmap. Defaults to true until we see a + // pixel with anything other than an alpha of 255. + bool is_opaque; + + // An intermediary buffer for decode output. + std::vector<unsigned char>* output; + + // Called to convert a row from the library to the correct output format. + // When NULL, no conversion is necessary. + void (*row_converter)(const unsigned char* in, + int w, + unsigned char* out, + bool* is_opaque); + + // Size of the image, set in the info callback. + int width; + int height; + + // Set to true when we've found the end of the data. + bool done; +}; + +void ConvertRGBtoRGBA(const unsigned char* rgb, + int pixel_width, + unsigned char* rgba, + bool* is_opaque) { + for (int x = 0; x < pixel_width; x++) { + const unsigned char* pixel_in = &rgb[x * 3]; + unsigned char* pixel_out = &rgba[x * 4]; + pixel_out[0] = pixel_in[0]; + pixel_out[1] = pixel_in[1]; + pixel_out[2] = pixel_in[2]; + pixel_out[3] = 0xff; + } +} + +void ConvertRGBtoBGRA(const unsigned char* rgb, + int pixel_width, + unsigned char* bgra, + bool* is_opaque) { + for (int x = 0; x < pixel_width; x++) { + const unsigned char* pixel_in = &rgb[x * 3]; + unsigned char* pixel_out = &bgra[x * 4]; + pixel_out[0] = pixel_in[2]; + pixel_out[1] = pixel_in[1]; + pixel_out[2] = pixel_in[0]; + pixel_out[3] = 0xff; + } +} + +// Called when the png header has been read. This code is based on the WebKit +// PNGImageDecoder +void DecodeInfoCallback(png_struct* png_ptr, png_info* info_ptr) { + PngDecoderState* state = + static_cast<PngDecoderState*>(png_get_progressive_ptr(png_ptr)); + + int bit_depth, color_type, interlace_type, compression_type; + int filter_type, channels; + png_uint_32 w, h; + png_get_IHDR(png_ptr, info_ptr, &w, &h, &bit_depth, &color_type, + &interlace_type, &compression_type, &filter_type); + + // Bounds check. When the image is unreasonably big, we'll error out and + // end up back at the setjmp call when we set up decoding. "Unreasonably big" + // means "big enough that w * h * 32bpp might overflow an int"; we choose this + // threshold to match WebKit and because a number of places in code assume + // that an image's size (in bytes) fits in a (signed) int. + unsigned long long total_size = + static_cast<unsigned long long>(w) * static_cast<unsigned long long>(h); + if (total_size > ((1 << 29) - 1)) + longjmp(png_jmpbuf(png_ptr), 1); + state->width = static_cast<int>(w); + state->height = static_cast<int>(h); + + // Expand to ensure we use 24-bit for RGB and 32-bit for RGBA. + if (color_type == PNG_COLOR_TYPE_PALETTE || + (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)) + png_set_expand(png_ptr); + + // Transparency for paletted images. + if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) + png_set_expand(png_ptr); + + // Convert 16-bit to 8-bit. + if (bit_depth == 16) + png_set_strip_16(png_ptr); + + // Expand grayscale to RGB. + if (color_type == PNG_COLOR_TYPE_GRAY || + color_type == PNG_COLOR_TYPE_GRAY_ALPHA) + png_set_gray_to_rgb(png_ptr); + + // Deal with gamma and keep it under our control. + double gamma; + if (png_get_gAMA(png_ptr, info_ptr, &gamma)) { + if (gamma <= 0.0 || gamma > kMaxGamma) { + gamma = kInverseGamma; + png_set_gAMA(png_ptr, info_ptr, gamma); + } + png_set_gamma(png_ptr, kDefaultGamma, gamma); + } else { + png_set_gamma(png_ptr, kDefaultGamma, kInverseGamma); + } + + // Tell libpng to send us rows for interlaced pngs. + if (interlace_type == PNG_INTERLACE_ADAM7) + png_set_interlace_handling(png_ptr); + + // Update our info now + png_read_update_info(png_ptr, info_ptr); + channels = png_get_channels(png_ptr, info_ptr); + + // Pick our row format converter necessary for this data. + if (channels == 3) { + switch (state->output_format) { + case FORMAT_RGB: + state->row_converter = NULL; // no conversion necessary + state->output_channels = 3; + break; + case FORMAT_RGBA: + state->row_converter = &ConvertRGBtoRGBA; + state->output_channels = 4; + break; + case FORMAT_BGRA: + state->row_converter = &ConvertRGBtoBGRA; + state->output_channels = 4; + break; + default: + NOTREACHED(); + break; + } + } else if (channels == 4) { + switch (state->output_format) { + case FORMAT_RGB: + state->row_converter = &ConvertRGBAtoRGB; + state->output_channels = 3; + break; + case FORMAT_RGBA: + state->row_converter = NULL; // no conversion necessary + state->output_channels = 4; + break; + case FORMAT_BGRA: + state->row_converter = &ConvertBetweenBGRAandRGBA; + state->output_channels = 4; + break; + default: + NOTREACHED(); + break; + } + } else { + NOTREACHED(); + longjmp(png_jmpbuf(png_ptr), 1); + } + + state->output->resize(state->width * state->output_channels * state->height); +} + +void DecodeRowCallback(png_struct* png_ptr, + png_byte* new_row, + png_uint_32 row_num, + int pass) { + PngDecoderState* state = + static_cast<PngDecoderState*>(png_get_progressive_ptr(png_ptr)); + + if (static_cast<int>(row_num) > state->height) { + NOTREACHED(); + return; + } + + unsigned char* base = NULL; + base = &state->output->front(); + + unsigned char* dest = &base[state->width * state->output_channels * row_num]; + if (state->row_converter) + state->row_converter(new_row, state->width, dest, &state->is_opaque); + else + memcpy(dest, new_row, state->width * state->output_channels); +} + +void DecodeEndCallback(png_struct* png_ptr, png_info* info) { + PngDecoderState* state = + static_cast<PngDecoderState*>(png_get_progressive_ptr(png_ptr)); + + // Mark the image as complete, this will tell the Decode function that we + // have successfully found the end of the data. + state->done = true; +} + +// Automatically destroys the given read structs on destruction to make +// cleanup and error handling code cleaner. +class PngReadStructDestroyer { + public: + PngReadStructDestroyer(png_struct** ps, png_info** pi) : ps_(ps), pi_(pi) {} + ~PngReadStructDestroyer() { png_destroy_read_struct(ps_, pi_, NULL); } + + private: + png_struct** ps_; + png_info** pi_; +}; + +bool BuildPNGStruct(const unsigned char* input, + size_t input_size, + png_struct** png_ptr, + png_info** info_ptr) { + if (input_size < 8) + return false; // Input data too small to be a png + + // Have libpng check the signature, it likes the first 8 bytes. + if (png_sig_cmp(const_cast<unsigned char*>(input), 0, 8) != 0) + return false; + + *png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL); + if (!*png_ptr) + return false; + + *info_ptr = png_create_info_struct(*png_ptr); + if (!*info_ptr) { + png_destroy_read_struct(png_ptr, NULL, NULL); + return false; + } + + return true; +} + +} // namespace + +// static +bool Decode(const unsigned char* input, + size_t input_size, + ColorFormat format, + std::vector<unsigned char>* output, + int* w, + int* h) { + png_struct* png_ptr = NULL; + png_info* info_ptr = NULL; + if (!BuildPNGStruct(input, input_size, &png_ptr, &info_ptr)) + return false; + + PngReadStructDestroyer destroyer(&png_ptr, &info_ptr); + if (setjmp(png_jmpbuf(png_ptr))) { + // The destroyer will ensure that the structures are cleaned up in this + // case, even though we may get here as a jump from random parts of the + // PNG library called below. + return false; + } + + PngDecoderState state(format, output); + + png_set_progressive_read_fn(png_ptr, &state, &DecodeInfoCallback, + &DecodeRowCallback, &DecodeEndCallback); + png_process_data(png_ptr, info_ptr, const_cast<unsigned char*>(input), + input_size); + + if (!state.done) { + // Fed it all the data but the library didn't think we got all the data, so + // this file must be truncated. + output->clear(); + return false; + } + + *w = state.width; + *h = state.height; + return true; +} + +// Encoder +// +// This section of the code is based on nsPNGEncoder.cpp in Mozilla +// (Copyright 2005 Google Inc.) + +namespace { + +// Passed around as the io_ptr in the png structs so our callbacks know where +// to write data. +struct PngEncoderState { + explicit PngEncoderState(std::vector<unsigned char>* o) : out(o) {} + std::vector<unsigned char>* out; +}; + +// Called by libpng to flush its internal buffer to ours. +void EncoderWriteCallback(png_structp png, png_bytep data, png_size_t size) { + PngEncoderState* state = static_cast<PngEncoderState*>(png_get_io_ptr(png)); + size_t old_size = state->out->size(); + state->out->resize(old_size + size); + memcpy(&(*state->out)[old_size], data, size); +} + +void FakeFlushCallback(png_structp png) { + // We don't need to perform any flushing since we aren't doing real IO, but + // we're required to provide this function by libpng. +} + +void ConvertBGRAtoRGB(const unsigned char* bgra, + int pixel_width, + unsigned char* rgb, + bool* is_opaque) { + for (int x = 0; x < pixel_width; x++) { + const unsigned char* pixel_in = &bgra[x * 4]; + unsigned char* pixel_out = &rgb[x * 3]; + pixel_out[0] = pixel_in[2]; + pixel_out[1] = pixel_in[1]; + pixel_out[2] = pixel_in[0]; + } +} + +#ifdef PNG_TEXT_SUPPORTED + +inline char* strdup(const char* str) { +#if defined(OS_WIN) + return _strdup(str); +#else + return ::strdup(str); +#endif +} + +class CommentWriter { + public: + explicit CommentWriter(const std::vector<Comment>& comments) + : comments_(comments), png_text_(new png_text[comments.size()]) { + for (size_t i = 0; i < comments.size(); ++i) + AddComment(i, comments[i]); + } + + ~CommentWriter() { + for (size_t i = 0; i < comments_.size(); ++i) { + free(png_text_[i].key); + free(png_text_[i].text); + } + delete[] png_text_; + } + + bool HasComments() { return !comments_.empty(); } + + png_text* get_png_text() { return png_text_; } + + int size() { return static_cast<int>(comments_.size()); } + + private: + void AddComment(size_t pos, const Comment& comment) { + png_text_[pos].compression = PNG_TEXT_COMPRESSION_NONE; + // A PNG comment's key can only be 79 characters long. + if (comment.key.length() > 79) + return; + png_text_[pos].key = strdup(comment.key.substr(0, 78).c_str()); + png_text_[pos].text = strdup(comment.text.c_str()); + png_text_[pos].text_length = comment.text.length(); +#ifdef PNG_iTXt_SUPPORTED + png_text_[pos].itxt_length = 0; + png_text_[pos].lang = 0; + png_text_[pos].lang_key = 0; +#endif + } + + const std::vector<Comment> comments_; + png_text* png_text_; +}; +#endif // PNG_TEXT_SUPPORTED + +// The type of functions usable for converting between pixel formats. +typedef void (*FormatConverter)(const unsigned char* in, + int w, + unsigned char* out, + bool* is_opaque); + +// libpng uses a wacky setjmp-based API, which makes the compiler nervous. +// We constrain all of the calls we make to libpng where the setjmp() is in +// place to this function. +// Returns true on success. +bool DoLibpngWrite(png_struct* png_ptr, + png_info* info_ptr, + PngEncoderState* state, + int width, + int height, + int row_byte_width, + const unsigned char* input, + int compression_level, + int png_output_color_type, + int output_color_components, + FormatConverter converter, + const std::vector<Comment>& comments) { +#ifdef PNG_TEXT_SUPPORTED + CommentWriter comment_writer(comments); +#endif + unsigned char* row_buffer = NULL; + + // Make sure to not declare any locals here -- locals in the presence + // of setjmp() in C++ code makes gcc complain. + + if (setjmp(png_jmpbuf(png_ptr))) { + delete[] row_buffer; + return false; + } + + png_set_compression_level(png_ptr, compression_level); + + // Set our callback for libpng to give us the data. + png_set_write_fn(png_ptr, state, EncoderWriteCallback, FakeFlushCallback); + + png_set_IHDR(png_ptr, info_ptr, width, height, 8, png_output_color_type, + PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, + PNG_FILTER_TYPE_DEFAULT); + +#ifdef PNG_TEXT_SUPPORTED + if (comment_writer.HasComments()) { + png_set_text(png_ptr, info_ptr, comment_writer.get_png_text(), + comment_writer.size()); + } +#endif + + png_write_info(png_ptr, info_ptr); + + if (!converter) { + // No conversion needed, give the data directly to libpng. + for (int y = 0; y < height; y++) { + png_write_row(png_ptr, + const_cast<unsigned char*>(&input[y * row_byte_width])); + } + } else { + // Needs conversion using a separate buffer. + row_buffer = new unsigned char[width * output_color_components]; + for (int y = 0; y < height; y++) { + converter(&input[y * row_byte_width], width, row_buffer, NULL); + png_write_row(png_ptr, row_buffer); + } + delete[] row_buffer; + } + + png_write_end(png_ptr, info_ptr); + return true; +} + +} // namespace + +// static +bool EncodeWithCompressionLevel(const unsigned char* input, + ColorFormat format, + const int width, + const int height, + int row_byte_width, + bool discard_transparency, + const std::vector<Comment>& comments, + int compression_level, + std::vector<unsigned char>* output) { + // Run to convert an input row into the output row format, NULL means no + // conversion is necessary. + FormatConverter converter = NULL; + + int input_color_components, output_color_components; + int png_output_color_type; + switch (format) { + case FORMAT_RGB: + input_color_components = 3; + output_color_components = 3; + png_output_color_type = PNG_COLOR_TYPE_RGB; + discard_transparency = false; + break; + + case FORMAT_RGBA: + input_color_components = 4; + if (discard_transparency) { + output_color_components = 3; + png_output_color_type = PNG_COLOR_TYPE_RGB; + converter = ConvertRGBAtoRGB; + } else { + output_color_components = 4; + png_output_color_type = PNG_COLOR_TYPE_RGB_ALPHA; + converter = NULL; + } + break; + + case FORMAT_BGRA: + input_color_components = 4; + if (discard_transparency) { + output_color_components = 3; + png_output_color_type = PNG_COLOR_TYPE_RGB; + converter = ConvertBGRAtoRGB; + } else { + output_color_components = 4; + png_output_color_type = PNG_COLOR_TYPE_RGB_ALPHA; + converter = ConvertBetweenBGRAandRGBA; + } + break; + + default: + NOTREACHED(); + return false; + } + + // Row stride should be at least as long as the length of the data. + if (input_color_components * width < row_byte_width) + return false; + + png_struct* png_ptr = + png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL); + if (!png_ptr) + return false; + png_info* info_ptr = png_create_info_struct(png_ptr); + if (!info_ptr) { + png_destroy_write_struct(&png_ptr, NULL); + return false; + } + + PngEncoderState state(output); + bool success = + DoLibpngWrite(png_ptr, info_ptr, &state, width, height, row_byte_width, + input, compression_level, png_output_color_type, + output_color_components, converter, comments); + png_destroy_write_struct(&png_ptr, &info_ptr); + + return success; +} + +// static +bool Encode(const unsigned char* input, + ColorFormat format, + const int width, + const int height, + int row_byte_width, + bool discard_transparency, + const std::vector<Comment>& comments, + std::vector<unsigned char>* output) { + return EncodeWithCompressionLevel(input, format, width, height, + row_byte_width, discard_transparency, + comments, Z_DEFAULT_COMPRESSION, output); +} + +// Decode a PNG into an RGBA pixel array. +bool DecodePNG(const unsigned char* input, + size_t input_size, + std::vector<unsigned char>* output, + int* width, + int* height) { + return Decode(input, input_size, FORMAT_RGBA, output, width, height); +} + +// Encode an RGBA pixel array into a PNG. +bool EncodeRGBAPNG(const unsigned char* input, + int width, + int height, + int row_byte_width, + std::vector<unsigned char>* output) { + return Encode(input, FORMAT_RGBA, width, height, row_byte_width, false, + std::vector<Comment>(), output); +} + +// Encode an BGRA pixel array into a PNG. +bool EncodeBGRAPNG(const unsigned char* input, + int width, + int height, + int row_byte_width, + bool discard_transparency, + std::vector<unsigned char>* output) { + return Encode(input, FORMAT_BGRA, width, height, row_byte_width, + discard_transparency, std::vector<Comment>(), output); +} + +} // namespace image_diff_png diff --git a/testing/image_diff/image_diff_png.h b/testing/image_diff/image_diff_png.h new file mode 100644 index 0000000000..4d87aa1cc0 --- /dev/null +++ b/testing/image_diff/image_diff_png.h @@ -0,0 +1,38 @@ +// Copyright 2013 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. + +#ifndef TESTING_IMAGE_DIFF_IMAGE_DIFF_PNG_H_ +#define TESTING_IMAGE_DIFF_IMAGE_DIFF_PNG_H_ + +#include <stdlib.h> // for size_t. + +#include <vector> + +namespace image_diff_png { + +// Decode a PNG into an RGBA pixel array. +bool DecodePNG(const unsigned char* input, + size_t input_size, + std::vector<unsigned char>* output, + int* width, + int* height); + +// Encode an RGBA pixel array into a PNG. +bool EncodeRGBAPNG(const unsigned char* input, + int width, + int height, + int row_byte_width, + std::vector<unsigned char>* output); + +// Encode an BGRA pixel array into a PNG. +bool EncodeBGRAPNG(const unsigned char* input, + int width, + int height, + int row_byte_width, + bool discard_transparency, + std::vector<unsigned char>* output); + +} // namespace image_diff_png + +#endif // TESTING_IMAGE_DIFF_IMAGE_DIFF_PNG_H_ |