src/cobalt/loader/image/animated_webp_image.cc - cobalt - Git at Google

 /*
  * Copyright 2017 Google Inc. All Rights Reserved.
  *
  * 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.
  */

 #include "cobalt/loader/image/animated_webp_image.h"

 #include "cobalt/loader/image/webp_image_decoder.h"
 #include "starboard/memory.h"

 namespace cobalt {
 namespace loader {
 namespace image {
 namespace {

 const int kPixelSize = 4;
 const int kLoopInfinite = 0;

 inline uint32_t DivideBy255(uint32_t value) {
   return (value + 1 + (value >> 8)) >> 8;
 }

 }  // namespace

 AnimatedWebPImage::AnimatedWebPImage(
     const math::Size& size, bool is_opaque,
     render_tree::ResourceProvider* resource_provider)
     : thread_("AnimatedWebPImage Decoding"),
       size_(size),
       is_opaque_(is_opaque),
       demux_(NULL),
       demux_state_(WEBP_DEMUX_PARSING_HEADER),
       frame_count_(0),
       loop_count_(kLoopInfinite),
       background_color_(0),
       should_dispose_previous_frame_(false),
       current_frame_index_(0),
       next_frame_index_(0),
       resource_provider_(resource_provider) {}

 scoped_refptr<render_tree::Image> AnimatedWebPImage::GetFrame() {
   base::AutoLock lock(lock_);
   return current_frame_image_;
 }

 void AnimatedWebPImage::AppendChunk(const uint8* data, size_t input_byte) {
   base::AutoLock lock(lock_);

   data_buffer_.insert(data_buffer_.end(), data, data + input_byte);
   WebPData webp_data = {&data_buffer_[0], data_buffer_.size()};
   WebPDemuxDelete(demux_);
   demux_ = WebPDemuxPartial(&webp_data, &demux_state_);
   DCHECK_GT(demux_state_, WEBP_DEMUX_PARSING_HEADER);

   // Update frame count.
   int new_frame_count = WebPDemuxGetI(demux_, WEBP_FF_FRAME_COUNT);
   if (new_frame_count > 0 && frame_count_ == 0) {
     // We've just received the first frame, start playing animation now.

     loop_count_ = WebPDemuxGetI(demux_, WEBP_FF_LOOP_COUNT);
     background_color_ = WebPDemuxGetI(demux_, WEBP_FF_BACKGROUND_COLOR);
     if (size_.width() > 0 && size_.height() > 0) {
       image_buffer_.resize(size_.width() * size_.height() * kPixelSize);
       FillImageBufferWithBackgroundColor();

       current_frame_time_ = base::TimeTicks::Now();
       current_frame_index_ = 0;
       thread_.Start();
       thread_.message_loop()->PostTask(
           FROM_HERE,
           base::Bind(&AnimatedWebPImage::DecodeFrames, base::Unretained(this)));
     }
   }
   frame_count_ = new_frame_count;
 }

 void AnimatedWebPImage::DecodeFrames() {
   TRACE_EVENT0("cobalt::loader::image", "AnimatedWebPImage::DecodeFrames()");
   base::AutoLock lock(lock_);

   UpdateTimelineInfo();

   // Decode the frames from current frame to next frame and blend the results.
   for (int frame_index = current_frame_index_ + 1;
        frame_index <= next_frame_index_; ++frame_index) {
     // Dispose previous frame if necessary.
     if (should_dispose_previous_frame_) {
       FillImageBufferWithBackgroundColor();
     }

     // Decode the current frame.
     WebPIterator webp_iterator;
     WebPDemuxGetFrame(demux_, frame_index, &webp_iterator);
     if (!webp_iterator.complete) {
       break;
     }
     WEBPImageDecoder webp_image_decoder(resource_provider_);
     webp_image_decoder.DecodeChunk(webp_iterator.fragment.bytes,
                                    webp_iterator.fragment.size);
     if (!webp_image_decoder.FinishWithSuccess()) {
       LOG(ERROR) << "Failed to decode WebP image frame.";
       break;
     }

     // Alpha blend the current frame on top of previous frame.
     {
       TRACE_EVENT0("cobalt::loader::image", "Blending");
       DCHECK(!image_buffer_.empty());
       uint8_t* image_buffer_memory = &image_buffer_[0];
       uint8_t* next_frame_memory = webp_image_decoder.GetOriginalMemory();
       // Alpha-blending: Given that each of the R, G, B and A channels is 8-bit,
       // and the RGB channels are not premultiplied by alpha, the formula for
       // blending 'dst' onto 'src' is:
       // blend.A = src.A + dst.A * (1 - src.A / 255)
       // if blend.A = 0 then
       //   blend.RGB = 0
       // else
       //   blend.RGB = (src.RGB * src.A +
       //                dst.RGB * dst.A * (1 - src.A / 255)) / blend.A
       //   https://developers.google.com/speed/webp/docs/riff_container#animation
       for (int y = 0; y < webp_iterator.height; ++y) {
         uint8_t* src =
             next_frame_memory + (y * webp_iterator.width) * kPixelSize;
         uint8_t* dst = image_buffer_memory +
                        ((y + webp_iterator.y_offset) * size_.width() +
                         webp_iterator.x_offset) *
                            kPixelSize;
         for (int x = 0; x < webp_iterator.width; ++x) {
           uint32_t dst_factor = dst[3] * (255 - src[3]);
           dst[3] = static_cast<uint8_t>(src[3] + DivideBy255(dst_factor));
           if (dst[3] == 0) {
             dst[0] = dst[1] = dst[2] = 0;
           } else {
             for (int i = 0; i < 3; ++i) {
               dst[i] = static_cast<uint8_t>(
                   (src[i] * src[3] + DivideBy255(dst[i] * dst_factor)) /
                   dst[3]);
             }
           }

           src += kPixelSize;
           dst += kPixelSize;
         }
       }
     }

     // Record the dispose method for current frame.
     should_dispose_previous_frame_ =
         webp_iterator.dispose_method == WEBP_MUX_DISPOSE_BACKGROUND;
     WebPDemuxReleaseIterator(&webp_iterator);
   }

   // Generate the next frame render tree image if necessary.
   if (current_frame_index_ != next_frame_index_) {
     current_frame_index_ = next_frame_index_;
     scoped_ptr<render_tree::ImageData> next_frame_data = AllocateImageData();
     DCHECK(next_frame_data);
     DCHECK(!image_buffer_.empty());
     uint8_t* image_buffer_memory = &image_buffer_[0];
     uint8_t* next_frame_memory = next_frame_data->GetMemory();
     SbMemoryCopy(next_frame_memory, image_buffer_memory,
                  size_.width() * size_.height() * kPixelSize);
     current_frame_image_ =
         resource_provider_->CreateImage(next_frame_data.Pass());
   }

   // Set up the next time to call the decode callback.
   base::TimeDelta delay = next_frame_time_ - base::TimeTicks::Now();
   if (delay < base::TimeDelta()) {
     delay = base::TimeDelta();
   }
   thread_.message_loop()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&AnimatedWebPImage::DecodeFrames, base::Unretained(this)),
       delay);

   if (!decoded_callback_.is_null()) {
     decoded_callback_.Run();
   }
 }

 void AnimatedWebPImage::UpdateTimelineInfo() {
   base::TimeTicks current_time = base::TimeTicks::Now();
   next_frame_index_ = current_frame_index_ ? current_frame_index_ : 1;
   while (true) {
     // Decode frames, until a frame such that the duration covers the current
     // time, i.e. the next frame should be displayed in the future.
     WebPIterator webp_iterator;
     WebPDemuxGetFrame(demux_, next_frame_index_, &webp_iterator);
     next_frame_time_ = current_frame_time_ + base::TimeDelta::FromMilliseconds(
                                                  webp_iterator.duration);
     WebPDemuxReleaseIterator(&webp_iterator);
     if (current_time < next_frame_time_) {
       break;
     }

     current_frame_time_ = next_frame_time_;
     if (next_frame_index_ < frame_count_) {
       next_frame_index_++;
     } else {
       DCHECK_EQ(next_frame_index_, frame_count_);
       // If the WebP image hasn't been fully fetched, or we've reached the end
       // of the last loop, then stop on the current frame.
       if (demux_state_ == WEBP_DEMUX_PARSED_HEADER || loop_count_ == 1) {
         break;
       }
       next_frame_index_ = 1;
       current_frame_index_ = 0;
       if (loop_count_ != kLoopInfinite) {
         loop_count_--;
       }
     }
   }
 }

 void AnimatedWebPImage::FillImageBufferWithBackgroundColor() {
   for (int y = 0; y < size_.height(); ++y) {
     for (int x = 0; x < size_.width(); ++x) {
       *reinterpret_cast<uint32_t*>(
           &image_buffer_[(y * size_.width() + x) * kPixelSize]) =
           background_color_;
     }
   }
 }

 AnimatedWebPImage::~AnimatedWebPImage() {
   WebPDemuxDelete(demux_);
   thread_.Stop();
 }

 scoped_ptr<render_tree::ImageData> AnimatedWebPImage::AllocateImageData() {
   render_tree::PixelFormat pixel_format = render_tree::kPixelFormatRGBA8;
   if (!resource_provider_->PixelFormatSupported(pixel_format)) {
     pixel_format = render_tree::kPixelFormatBGRA8;
   }
   scoped_ptr<render_tree::ImageData> image_data =
       resource_provider_->AllocateImageData(
           size_, pixel_format, render_tree::kAlphaFormatPremultiplied);
   DCHECK(image_data) << "Failed to allocate image.";
   return image_data.Pass();
 }

 }  // namespace image
 }  // namespace loader
 }  // namespace cobalt
	/*
	* Copyright 2017 Google Inc. All Rights Reserved.
	*
	* 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.
	*/

	#include "cobalt/loader/image/animated_webp_image.h"

	#include "cobalt/loader/image/webp_image_decoder.h"
	#include "starboard/memory.h"

	namespace cobalt {
	namespace loader {
	namespace image {
	namespace {

	const int kPixelSize = 4;
	const int kLoopInfinite = 0;

	inline uint32_t DivideBy255(uint32_t value) {
	return (value + 1 + (value >> 8)) >> 8;
	}

	} // namespace

	AnimatedWebPImage::AnimatedWebPImage(
	const math::Size& size, bool is_opaque,
	render_tree::ResourceProvider* resource_provider)
	: thread_("AnimatedWebPImage Decoding"),
	size_(size),
	is_opaque_(is_opaque),
	demux_(NULL),
	demux_state_(WEBP_DEMUX_PARSING_HEADER),
	frame_count_(0),
	loop_count_(kLoopInfinite),
	background_color_(0),
	should_dispose_previous_frame_(false),
	current_frame_index_(0),
	next_frame_index_(0),
	resource_provider_(resource_provider) {}

	scoped_refptr<render_tree::Image> AnimatedWebPImage::GetFrame() {
	base::AutoLock lock(lock_);
	return current_frame_image_;
	}

	void AnimatedWebPImage::AppendChunk(const uint8* data, size_t input_byte) {
	base::AutoLock lock(lock_);

	data_buffer_.insert(data_buffer_.end(), data, data + input_byte);
	WebPData webp_data = {&data_buffer_[0], data_buffer_.size()};
	WebPDemuxDelete(demux_);
	demux_ = WebPDemuxPartial(&webp_data, &demux_state_);
	DCHECK_GT(demux_state_, WEBP_DEMUX_PARSING_HEADER);

	// Update frame count.
	int new_frame_count = WebPDemuxGetI(demux_, WEBP_FF_FRAME_COUNT);
	if (new_frame_count > 0 && frame_count_ == 0) {
	// We've just received the first frame, start playing animation now.

	loop_count_ = WebPDemuxGetI(demux_, WEBP_FF_LOOP_COUNT);
	background_color_ = WebPDemuxGetI(demux_, WEBP_FF_BACKGROUND_COLOR);
	if (size_.width() > 0 && size_.height() > 0) {
	image_buffer_.resize(size_.width() * size_.height() * kPixelSize);
	FillImageBufferWithBackgroundColor();

	current_frame_time_ = base::TimeTicks::Now();
	current_frame_index_ = 0;
	thread_.Start();
	thread_.message_loop()->PostTask(
	FROM_HERE,
	base::Bind(&AnimatedWebPImage::DecodeFrames, base::Unretained(this)));
	}
	}
	frame_count_ = new_frame_count;
	}

	void AnimatedWebPImage::DecodeFrames() {
	TRACE_EVENT0("cobalt::loader::image", "AnimatedWebPImage::DecodeFrames()");
	base::AutoLock lock(lock_);

	UpdateTimelineInfo();

	// Decode the frames from current frame to next frame and blend the results.
	for (int frame_index = current_frame_index_ + 1;
	frame_index <= next_frame_index_; ++frame_index) {
	// Dispose previous frame if necessary.
	if (should_dispose_previous_frame_) {
	FillImageBufferWithBackgroundColor();
	}

	// Decode the current frame.
	WebPIterator webp_iterator;
	WebPDemuxGetFrame(demux_, frame_index, &webp_iterator);
	if (!webp_iterator.complete) {
	break;
	}
	WEBPImageDecoder webp_image_decoder(resource_provider_);
	webp_image_decoder.DecodeChunk(webp_iterator.fragment.bytes,
	webp_iterator.fragment.size);
	if (!webp_image_decoder.FinishWithSuccess()) {
	LOG(ERROR) << "Failed to decode WebP image frame.";
	break;
	}

	// Alpha blend the current frame on top of previous frame.
	{
	TRACE_EVENT0("cobalt::loader::image", "Blending");
	DCHECK(!image_buffer_.empty());
	uint8_t* image_buffer_memory = &image_buffer_[0];
	uint8_t* next_frame_memory = webp_image_decoder.GetOriginalMemory();
	// Alpha-blending: Given that each of the R, G, B and A channels is 8-bit,
	// and the RGB channels are not premultiplied by alpha, the formula for
	// blending 'dst' onto 'src' is:
	// blend.A = src.A + dst.A * (1 - src.A / 255)
	// if blend.A = 0 then
	// blend.RGB = 0
	// else
	// blend.RGB = (src.RGB * src.A +
	// dst.RGB * dst.A * (1 - src.A / 255)) / blend.A
	// https://developers.google.com/speed/webp/docs/riff_container#animation
	for (int y = 0; y < webp_iterator.height; ++y) {
	uint8_t* src =
	next_frame_memory + (y * webp_iterator.width) * kPixelSize;
	uint8_t* dst = image_buffer_memory +
	((y + webp_iterator.y_offset) * size_.width() +
	webp_iterator.x_offset) *
	kPixelSize;
	for (int x = 0; x < webp_iterator.width; ++x) {
	uint32_t dst_factor = dst[3] * (255 - src[3]);
	dst[3] = static_cast<uint8_t>(src[3] + DivideBy255(dst_factor));
	if (dst[3] == 0) {
	dst[0] = dst[1] = dst[2] = 0;
	} else {
	for (int i = 0; i < 3; ++i) {
	dst[i] = static_cast<uint8_t>(
	(src[i] * src[3] + DivideBy255(dst[i] * dst_factor)) /
	dst[3]);
	}
	}

	src += kPixelSize;
	dst += kPixelSize;
	}
	}
	}

	// Record the dispose method for current frame.
	should_dispose_previous_frame_ =
	webp_iterator.dispose_method == WEBP_MUX_DISPOSE_BACKGROUND;
	WebPDemuxReleaseIterator(&webp_iterator);
	}

	// Generate the next frame render tree image if necessary.
	if (current_frame_index_ != next_frame_index_) {
	current_frame_index_ = next_frame_index_;
	scoped_ptr<render_tree::ImageData> next_frame_data = AllocateImageData();
	DCHECK(next_frame_data);
	DCHECK(!image_buffer_.empty());
	uint8_t* image_buffer_memory = &image_buffer_[0];
	uint8_t* next_frame_memory = next_frame_data->GetMemory();
	SbMemoryCopy(next_frame_memory, image_buffer_memory,
	size_.width() * size_.height() * kPixelSize);
	current_frame_image_ =
	resource_provider_->CreateImage(next_frame_data.Pass());
	}

	// Set up the next time to call the decode callback.
	base::TimeDelta delay = next_frame_time_ - base::TimeTicks::Now();
	if (delay < base::TimeDelta()) {
	delay = base::TimeDelta();
	}
	thread_.message_loop()->PostDelayedTask(
	FROM_HERE,
	base::Bind(&AnimatedWebPImage::DecodeFrames, base::Unretained(this)),
	delay);

	if (!decoded_callback_.is_null()) {
	decoded_callback_.Run();
	}
	}

	void AnimatedWebPImage::UpdateTimelineInfo() {
	base::TimeTicks current_time = base::TimeTicks::Now();
	next_frame_index_ = current_frame_index_ ? current_frame_index_ : 1;
	while (true) {
	// Decode frames, until a frame such that the duration covers the current
	// time, i.e. the next frame should be displayed in the future.
	WebPIterator webp_iterator;
	WebPDemuxGetFrame(demux_, next_frame_index_, &webp_iterator);
	next_frame_time_ = current_frame_time_ + base::TimeDelta::FromMilliseconds(
	webp_iterator.duration);
	WebPDemuxReleaseIterator(&webp_iterator);
	if (current_time < next_frame_time_) {
	break;
	}

	current_frame_time_ = next_frame_time_;
	if (next_frame_index_ < frame_count_) {
	next_frame_index_++;
	} else {
	DCHECK_EQ(next_frame_index_, frame_count_);
	// If the WebP image hasn't been fully fetched, or we've reached the end
	// of the last loop, then stop on the current frame.
	if (demux_state_ == WEBP_DEMUX_PARSED_HEADER \|\| loop_count_ == 1) {
	break;
	}
	next_frame_index_ = 1;
	current_frame_index_ = 0;
	if (loop_count_ != kLoopInfinite) {
	loop_count_--;
	}
	}
	}
	}

	void AnimatedWebPImage::FillImageBufferWithBackgroundColor() {
	for (int y = 0; y < size_.height(); ++y) {
	for (int x = 0; x < size_.width(); ++x) {
	reinterpret_cast<uint32_t>(
	&image_buffer_[(y * size_.width() + x) * kPixelSize]) =
	background_color_;
	}
	}
	}

	AnimatedWebPImage::~AnimatedWebPImage() {
	WebPDemuxDelete(demux_);
	thread_.Stop();
	}

	scoped_ptr<render_tree::ImageData> AnimatedWebPImage::AllocateImageData() {
	render_tree::PixelFormat pixel_format = render_tree::kPixelFormatRGBA8;
	if (!resource_provider_->PixelFormatSupported(pixel_format)) {
	pixel_format = render_tree::kPixelFormatBGRA8;
	}
	scoped_ptr<render_tree::ImageData> image_data =
	resource_provider_->AllocateImageData(
	size_, pixel_format, render_tree::kAlphaFormatPremultiplied);
	DCHECK(image_data) << "Failed to allocate image.";
	return image_data.Pass();
	}

	} // namespace image
	} // namespace loader
	} // namespace cobalt