src/net/instaweb/spriter/libpng_image_library.cc - incubator-pagespeed-debian - Git at Google

 /*
  * Copyright 2011 Google Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 // Author: abliss@google.com (Adam Bliss)

 #include "net/instaweb/spriter/libpng_image_library.h"

 #include <errno.h>

 #include "pagespeed/kernel/base/string.h"
 #include "pagespeed/kernel/base/string_util.h"

 namespace {

 // We always output at RGBA with 8 bits per channel.
 const int BYTES_PER_PIXEL = 4;
 // Largest PNG dimension (width or height) that we will attempt to process.
 const int MAX_PNG_DIMENSION = 4096;

 }  // namespace
 namespace net_instaweb {
 namespace spriter {

 LibpngImageLibrary::Image::Image(ImageLibraryInterface* lib,
                                  png_structp png_struct, png_infop png_info,
                                  png_bytep* rows)
     : ImageLibraryInterface::Image(lib),
       png_struct_(png_struct), png_info_(png_info), rows_(rows) {
 }
 LibpngImageLibrary::Image::~Image() {
   int width, height;
   GetDimensions(&width, &height);
   png_destroy_read_struct(&png_struct_, &png_info_, NULL);
   for (int i = height - 1; i >= 0; i--) {
     delete[] rows_[i];
   }
   delete[] rows_;
 }
 bool LibpngImageLibrary::Image::GetDimensions(int* out_width, int* out_height)
     const {
   *out_width = png_get_image_width(png_struct_, png_info_);
   *out_height = png_get_image_height(png_struct_, png_info_);
   return true;
 }
 const png_bytep* LibpngImageLibrary::Image::Rows() const {
   return rows_;
 }

 bool LibpngImageLibrary::Canvas::DrawImage(
     const ImageLibraryInterface::Image* image, int x_start, int y_start) {
   int w, h;
   image->GetDimensions(&w, &h);
   if ((w <= 0) || (h <= 0)) {
     return true;
   }
   const png_bytep* rows = static_cast<const Image*>(image)->Rows();
   int their_y = h - 1;
   int my_y = y_start + h - 1;
   int x_start_byte = x_start * BYTES_PER_PIXEL;
   int num_bytes = w * BYTES_PER_PIXEL;
   CHECK(x_start >= 0);
   CHECK(y_start >= 0);
   CHECK(x_start + w <= width_);
   CHECK(y_start + h <= height_);
   while (their_y >= 0) {
     memcpy(rows_[my_y] + x_start_byte, rows[their_y], num_bytes);
     their_y--;
     my_y--;
   }
   return true;
 }

 bool LibpngImageLibrary::Canvas::WriteToFile(const FilePath& filename,
                                              ImageFormat format) {
   GoogleString write_path = StrCat(base_out_path_, filename);
   FILE* file = fopen(write_path.c_str(), "wb");
   if (file == NULL) {
     delegate_->OnError(
         StrCat("Writing image " , write_path, ": ", strerror(errno)));
     fclose(file);
     return false;
   }

   png_structp png_struct = png_create_write_struct(
       PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
   if (png_struct == NULL) {
     delegate_->OnError(
         StrCat("Writing image " , write_path, ": cannot create png struct"));
     fclose(file);
     return false;
   }
   png_infop png_info = png_create_info_struct(png_struct);
   if (png_info == NULL) {
     delegate_->OnError(
         StrCat("Writing image " , write_path, ": cannot create png info"));
     png_destroy_write_struct(&png_struct, &png_info);
     fclose(file);
     return false;
   }
   if (setjmp(png_jmpbuf(png_struct))) {
     delegate_->OnError(
         StrCat("Writing image " , write_path, ": cannot initialize libpng"));
     png_destroy_write_struct(&png_struct, &png_info);
     fclose(file);
     return false;
   }
   png_init_io(png_struct, file);
   if (setjmp(png_jmpbuf(png_struct))) {
     delegate_->OnError(
         StrCat("Writing image " , write_path, ": cannot write header"));
     png_destroy_write_struct(&png_struct, &png_info);
     fclose(file);
     return false;
   }
   const png_byte bit_depth = 8;
   const png_byte color_type = PNG_COLOR_TYPE_RGB_ALPHA;
   png_set_IHDR(png_struct, png_info, width_, height_,
                bit_depth, color_type, PNG_INTERLACE_NONE,
                PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
   png_write_info(png_struct, png_info);

   if (setjmp(png_jmpbuf(png_struct))) {
     delegate_->OnError(
         StrCat("Writing image " , write_path, ": cannot write body"));
     png_destroy_write_struct(&png_struct, &png_info);
     fclose(file);
     return false;
   }
   png_write_image(png_struct, rows_);

   if (setjmp(png_jmpbuf(png_struct))) {
     delegate_->OnError(
         StrCat("Writing image " , write_path, ": cannot write end"));
     fclose(file);
     return false;
   }
   png_write_end(png_struct, NULL);
   png_destroy_write_struct(&png_struct, &png_info);
   if (fclose(file) != 0) {
     delegate_->OnError(
         StrCat("Writing image " , write_path, ": ", strerror(errno)));
     return false;
   }
   return true;
 }
 LibpngImageLibrary::Canvas::Canvas(ImageLibraryInterface* lib,
                                    const Delegate* d,
                                    const GoogleString& base_out_path,
                                    int width, int height)
     : ImageLibraryInterface::Canvas(lib), delegate_(d),
       base_out_path_(base_out_path), width_(width), height_(height) {
   rows_ = new png_bytep[height];
   for (int i = height - 1; i >= 0; i--) {
     rows_[i] = new png_byte[width * BYTES_PER_PIXEL];
     memset(rows_[i], 0, width * BYTES_PER_PIXEL);
   }
 }
 LibpngImageLibrary::Canvas::~Canvas() {
   for (int i = height_ - 1; i >= 0; i--) {
     delete[] rows_[i];
   }
   delete[] rows_;
 }
 ImageLibraryInterface::Canvas* LibpngImageLibrary::CreateCanvas(int width,
                                                                 int height) {
   return new Canvas(this, delegate(), base_output_path(), width, height);
 }


 // Read an image from disk.  Return NULL (after calling delegate
 // method) on error.  Caller owns the returned pointer.
 ImageLibraryInterface::Image* LibpngImageLibrary::ReadFromFile(
     const FilePath& filename) {
   GoogleString path = StrCat(base_input_path(), filename);
   FILE* file = fopen(path.c_str(), "rb");
   if (file == NULL) {
     delegate()->OnError(StrCat("Reading image " , path, ": ", strerror(errno)));
     return NULL;
   }
   png_byte header[8];
   if (fread(header, 1, 8, file) != 8) {
     delegate()->OnError(StrCat("Image " , path, " has no header."));
     fclose(file);
     return NULL;
   }
   if (png_sig_cmp(header, 0, 8) != 0) {
     delegate()->OnError(StrCat("Image " , path, " not PNG."));
     fclose(file);
     return NULL;
   }
   png_structp png_struct = png_create_read_struct(PNG_LIBPNG_VER_STRING,
                                                   NULL, NULL, NULL);
   png_infop png_info = png_create_info_struct(png_struct);
   if (!png_info) {
     png_destroy_read_struct(&png_struct, NULL, NULL);
     delegate()->OnError(StrCat("Image " , path, " could not create png_info"));
     return NULL;
   }
   if (setjmp(png_jmpbuf(png_struct))) {
     png_destroy_read_struct(&png_struct, &png_info, NULL);
     fclose(file);
     delegate()->OnError(StrCat("Image " , path, " could not be decoded."));
     return NULL;
   }
   png_init_io(png_struct, file);
   png_set_sig_bytes(png_struct, 8);
   png_read_info(png_struct, png_info);
   int width = png_get_image_width(png_struct, png_info);
   int height = png_get_image_height(png_struct, png_info);
   if ((width > MAX_PNG_DIMENSION) || (height > MAX_PNG_DIMENSION)) {
     fclose(file);
     delegate()->OnError(StrCat("Image " , path, " is too big."));
     return NULL;
   }
   if ((width <= 0) || (height <= 0)) {
     delegate()->OnError(StrCat("Image " , path, " has nonpositive dimension."));
     return NULL;
   }

   // Expand the image to 8-bit RGBA.  Code taken from libpng manpage.
   int color_type = png_get_color_type(png_struct, png_info);
   int bit_depth = png_get_bit_depth(png_struct, png_info);
   if (color_type == PNG_COLOR_TYPE_PALETTE) {
     png_set_palette_to_rgb(png_struct);
   }
   if ((color_type == PNG_COLOR_TYPE_GRAY) && (bit_depth < 8)) {
     png_set_expand_gray_1_2_4_to_8(png_struct);
   }
   if (png_get_valid(png_struct, png_info, PNG_INFO_tRNS)) {
     png_set_tRNS_to_alpha(png_struct);
   }
   if (bit_depth == 16) {
     png_set_strip_16(png_struct);
   }
   if (bit_depth < 8) {
     png_set_packing(png_struct);
   }
   if ((color_type == PNG_COLOR_TYPE_RGB) ||
       (color_type == PNG_COLOR_TYPE_GRAY)) {
     png_set_add_alpha(png_struct, 0xff, PNG_FILLER_AFTER);
   }
   if ((color_type == PNG_COLOR_TYPE_GRAY) ||
       (color_type == PNG_COLOR_TYPE_GRAY_ALPHA)) {
         png_set_gray_to_rgb(png_struct);
   }
   // TODO(abliss): what to do with background color and gamma?
   png_read_update_info(png_struct, png_info);
   png_bytep* rows = new png_bytep[height];
   for (int i = height - 1; i >= 0; i--) {
     rows[i] = new png_byte[width * BYTES_PER_PIXEL];
   }
   png_read_image(png_struct, rows);
   png_read_end(png_struct, png_info);
   fclose(file);
   return new Image(this, png_struct, png_info, rows);
 }


 LibpngImageLibrary::LibpngImageLibrary(const FilePath& base_input_path,
                                        const FilePath& base_output_path,
                                        Delegate* delegate)
     : ImageLibraryInterface(base_input_path, base_output_path, delegate) {
 }


 }  // namespace spriter
 }  // namespace net_instaweb
	/*
	* Copyright 2011 Google Inc.
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/
	// Author: abliss@google.com (Adam Bliss)

	#include "net/instaweb/spriter/libpng_image_library.h"

	#include <errno.h>

	#include "pagespeed/kernel/base/string.h"
	#include "pagespeed/kernel/base/string_util.h"

	namespace {

	// We always output at RGBA with 8 bits per channel.
	const int BYTES_PER_PIXEL = 4;
	// Largest PNG dimension (width or height) that we will attempt to process.
	const int MAX_PNG_DIMENSION = 4096;

	} // namespace
	namespace net_instaweb {
	namespace spriter {

	LibpngImageLibrary::Image::Image(ImageLibraryInterface* lib,
	png_structp png_struct, png_infop png_info,
	png_bytep* rows)
	: ImageLibraryInterface::Image(lib),
	png_struct_(png_struct), png_info_(png_info), rows_(rows) {
	}
	LibpngImageLibrary::Image::~Image() {
	int width, height;
	GetDimensions(&width, &height);
	png_destroy_read_struct(&png_struct_, &png_info_, NULL);
	for (int i = height - 1; i >= 0; i--) {
	delete[] rows_[i];
	}
	delete[] rows_;
	}
	bool LibpngImageLibrary::Image::GetDimensions(int* out_width, int* out_height)
	const {
	*out_width = png_get_image_width(png_struct_, png_info_);
	*out_height = png_get_image_height(png_struct_, png_info_);
	return true;
	}
	const png_bytep* LibpngImageLibrary::Image::Rows() const {
	return rows_;
	}

	bool LibpngImageLibrary::Canvas::DrawImage(
	const ImageLibraryInterface::Image* image, int x_start, int y_start) {
	int w, h;
	image->GetDimensions(&w, &h);
	if ((w <= 0) \|\| (h <= 0)) {
	return true;
	}
	const png_bytep* rows = static_cast<const Image*>(image)->Rows();
	int their_y = h - 1;
	int my_y = y_start + h - 1;
	int x_start_byte = x_start * BYTES_PER_PIXEL;
	int num_bytes = w * BYTES_PER_PIXEL;
	CHECK(x_start >= 0);
	CHECK(y_start >= 0);
	CHECK(x_start + w <= width_);
	CHECK(y_start + h <= height_);
	while (their_y >= 0) {
	memcpy(rows_[my_y] + x_start_byte, rows[their_y], num_bytes);
	their_y--;
	my_y--;
	}
	return true;
	}

	bool LibpngImageLibrary::Canvas::WriteToFile(const FilePath& filename,
	ImageFormat format) {
	GoogleString write_path = StrCat(base_out_path_, filename);
	FILE* file = fopen(write_path.c_str(), "wb");
	if (file == NULL) {
	delegate_->OnError(
	StrCat("Writing image " , write_path, ": ", strerror(errno)));
	fclose(file);
	return false;
	}

	png_structp png_struct = png_create_write_struct(
	PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
	if (png_struct == NULL) {
	delegate_->OnError(
	StrCat("Writing image " , write_path, ": cannot create png struct"));
	fclose(file);
	return false;
	}
	png_infop png_info = png_create_info_struct(png_struct);
	if (png_info == NULL) {
	delegate_->OnError(
	StrCat("Writing image " , write_path, ": cannot create png info"));
	png_destroy_write_struct(&png_struct, &png_info);
	fclose(file);
	return false;
	}
	if (setjmp(png_jmpbuf(png_struct))) {
	delegate_->OnError(
	StrCat("Writing image " , write_path, ": cannot initialize libpng"));
	png_destroy_write_struct(&png_struct, &png_info);
	fclose(file);
	return false;
	}
	png_init_io(png_struct, file);
	if (setjmp(png_jmpbuf(png_struct))) {
	delegate_->OnError(
	StrCat("Writing image " , write_path, ": cannot write header"));
	png_destroy_write_struct(&png_struct, &png_info);
	fclose(file);
	return false;
	}
	const png_byte bit_depth = 8;
	const png_byte color_type = PNG_COLOR_TYPE_RGB_ALPHA;
	png_set_IHDR(png_struct, png_info, width_, height_,
	bit_depth, color_type, PNG_INTERLACE_NONE,
	PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
	png_write_info(png_struct, png_info);

	if (setjmp(png_jmpbuf(png_struct))) {
	delegate_->OnError(
	StrCat("Writing image " , write_path, ": cannot write body"));
	png_destroy_write_struct(&png_struct, &png_info);
	fclose(file);
	return false;
	}
	png_write_image(png_struct, rows_);

	if (setjmp(png_jmpbuf(png_struct))) {
	delegate_->OnError(
	StrCat("Writing image " , write_path, ": cannot write end"));
	fclose(file);
	return false;
	}
	png_write_end(png_struct, NULL);
	png_destroy_write_struct(&png_struct, &png_info);
	if (fclose(file) != 0) {
	delegate_->OnError(
	StrCat("Writing image " , write_path, ": ", strerror(errno)));
	return false;
	}
	return true;
	}
	LibpngImageLibrary::Canvas::Canvas(ImageLibraryInterface* lib,
	const Delegate* d,
	const GoogleString& base_out_path,
	int width, int height)
	: ImageLibraryInterface::Canvas(lib), delegate_(d),
	base_out_path_(base_out_path), width_(width), height_(height) {
	rows_ = new png_bytep[height];
	for (int i = height - 1; i >= 0; i--) {
	rows_[i] = new png_byte[width * BYTES_PER_PIXEL];
	memset(rows_[i], 0, width * BYTES_PER_PIXEL);
	}
	}
	LibpngImageLibrary::Canvas::~Canvas() {
	for (int i = height_ - 1; i >= 0; i--) {
	delete[] rows_[i];
	}
	delete[] rows_;
	}
	ImageLibraryInterface::Canvas* LibpngImageLibrary::CreateCanvas(int width,
	int height) {
	return new Canvas(this, delegate(), base_output_path(), width, height);
	}


	// Read an image from disk. Return NULL (after calling delegate
	// method) on error. Caller owns the returned pointer.
	ImageLibraryInterface::Image* LibpngImageLibrary::ReadFromFile(
	const FilePath& filename) {
	GoogleString path = StrCat(base_input_path(), filename);
	FILE* file = fopen(path.c_str(), "rb");
	if (file == NULL) {
	delegate()->OnError(StrCat("Reading image " , path, ": ", strerror(errno)));
	return NULL;
	}
	png_byte header[8];
	if (fread(header, 1, 8, file) != 8) {
	delegate()->OnError(StrCat("Image " , path, " has no header."));
	fclose(file);
	return NULL;
	}
	if (png_sig_cmp(header, 0, 8) != 0) {
	delegate()->OnError(StrCat("Image " , path, " not PNG."));
	fclose(file);
	return NULL;
	}
	png_structp png_struct = png_create_read_struct(PNG_LIBPNG_VER_STRING,
	NULL, NULL, NULL);
	png_infop png_info = png_create_info_struct(png_struct);
	if (!png_info) {
	png_destroy_read_struct(&png_struct, NULL, NULL);
	delegate()->OnError(StrCat("Image " , path, " could not create png_info"));
	return NULL;
	}
	if (setjmp(png_jmpbuf(png_struct))) {
	png_destroy_read_struct(&png_struct, &png_info, NULL);
	fclose(file);
	delegate()->OnError(StrCat("Image " , path, " could not be decoded."));
	return NULL;
	}
	png_init_io(png_struct, file);
	png_set_sig_bytes(png_struct, 8);
	png_read_info(png_struct, png_info);
	int width = png_get_image_width(png_struct, png_info);
	int height = png_get_image_height(png_struct, png_info);
	if ((width > MAX_PNG_DIMENSION) \|\| (height > MAX_PNG_DIMENSION)) {
	fclose(file);
	delegate()->OnError(StrCat("Image " , path, " is too big."));
	return NULL;
	}
	if ((width <= 0) \|\| (height <= 0)) {
	delegate()->OnError(StrCat("Image " , path, " has nonpositive dimension."));
	return NULL;
	}

	// Expand the image to 8-bit RGBA. Code taken from libpng manpage.
	int color_type = png_get_color_type(png_struct, png_info);
	int bit_depth = png_get_bit_depth(png_struct, png_info);
	if (color_type == PNG_COLOR_TYPE_PALETTE) {
	png_set_palette_to_rgb(png_struct);
	}
	if ((color_type == PNG_COLOR_TYPE_GRAY) && (bit_depth < 8)) {
	png_set_expand_gray_1_2_4_to_8(png_struct);
	}
	if (png_get_valid(png_struct, png_info, PNG_INFO_tRNS)) {
	png_set_tRNS_to_alpha(png_struct);
	}
	if (bit_depth == 16) {
	png_set_strip_16(png_struct);
	}
	if (bit_depth < 8) {
	png_set_packing(png_struct);
	}
	if ((color_type == PNG_COLOR_TYPE_RGB) \|\|
	(color_type == PNG_COLOR_TYPE_GRAY)) {
	png_set_add_alpha(png_struct, 0xff, PNG_FILLER_AFTER);
	}
	if ((color_type == PNG_COLOR_TYPE_GRAY) \|\|
	(color_type == PNG_COLOR_TYPE_GRAY_ALPHA)) {
	png_set_gray_to_rgb(png_struct);
	}
	// TODO(abliss): what to do with background color and gamma?
	png_read_update_info(png_struct, png_info);
	png_bytep* rows = new png_bytep[height];
	for (int i = height - 1; i >= 0; i--) {
	rows[i] = new png_byte[width * BYTES_PER_PIXEL];
	}
	png_read_image(png_struct, rows);
	png_read_end(png_struct, png_info);
	fclose(file);
	return new Image(this, png_struct, png_info, rows);
	}


	LibpngImageLibrary::LibpngImageLibrary(const FilePath& base_input_path,
	const FilePath& base_output_path,
	Delegate* delegate)
	: ImageLibraryInterface(base_input_path, base_output_path, delegate) {
	}


	} // namespace spriter
	} // namespace net_instaweb