Update the pdfium library
Note: pdfium does not have releases, rather the repository is
kept up-to-date. This was pulled on: 6/4/2015.
Change-Id: I3c6d77fa1f7c6da2b7df3c4e5c00093900125bc2
diff --git a/samples/image_diff_png.cc b/samples/image_diff_png.cc
new file mode 100644
index 0000000..04c2591
--- /dev/null
+++ b/samples/image_diff_png.cc
@@ -0,0 +1,644 @@
+// 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 "image_diff_png.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+#include <string>
+
+#include "../third_party/base/logging.h"
+#include "../core/src/fxcodec/fx_zlib/include/fx_zlib.h"
+#include "fx_lpng/include/fx_png.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);
+}
+
+} // image_diff_png