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/*
* Copyright 2015 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.
*/
#ifndef COBALT_LOADER_IMAGE_IMAGE_DATA_DECODER_H_
#define COBALT_LOADER_IMAGE_IMAGE_DATA_DECODER_H_
#include <string>
#include <vector>
#include "cobalt/render_tree/image.h"
#include "cobalt/render_tree/resource_provider.h"
#if defined(STARBOARD)
#include "starboard/decode_target.h"
#endif
namespace cobalt {
namespace loader {
namespace image {
// This class is used as a component of ImageDecoder and is intended to be
// sub-classed by specific data decoders, such as JPEG decoders and PNG
// decoders. This class is intended to decode image data based on the type,
// but leaves the responsibility of handling callbacks and producing the final
// image to ImageDecoder.
class ImageDataDecoder {
public:
explicit ImageDataDecoder(render_tree::ResourceProvider* resource_provider);
virtual ~ImageDataDecoder() {}
virtual std::string GetTypeString() const = 0;
scoped_ptr<render_tree::ImageData> RetrieveImageData() {
return image_data_.Pass();
}
#if defined(STARBOARD)
#if SB_VERSION(3) && SB_HAS(GRAPHICS)
// Starboard version 3 adds support for hardware accelerated image decoding.
// In order to make use of this feature, subclasses of ImageDataDecoder may
// override this method in order to return an SbDecodeTarget, rather than a
// render_tree::ImageData, which could potentially save a copy from CPU
// memory to GPU memory, depending on the render_tree implementation and
// hardware image decoding functionality available. If
// |RetrieveSbDecodeTarget| returns any value other than the default
// |kSbDecodeInvalid|, ImageDecoder will interpret it as a preference
// towards SbDecodeTarget rather than render_tree::ImageData.
virtual SbDecodeTarget RetrieveSbDecodeTarget() {
return kSbDecodeTargetInvalid;
}
#endif // SB_VERSION(3) && SB_HAS(GRAPHICS)
#endif // defined(STARBOARD)
void DecodeChunk(const uint8* data, size_t size);
// Return true if decoding succeeded.
bool FinishWithSuccess();
protected:
enum State {
kWaitingForHeader,
kReadLines,
kDone,
kError,
};
// Every subclass of ImageDataDecoder should override this function to do
// the internal decoding. The return value of this function is the number of
// decoded data.
virtual size_t DecodeChunkInternal(const uint8* data, size_t input_byte) = 0;
// Subclass can override this function to get a last chance to do some work.
virtual void FinishInternal() {}
void AllocateImageData(const math::Size& size, bool has_alpha);
render_tree::ImageData* image_data() const { return image_data_.get(); }
void set_state(State state) { state_ = state; }
State state() const { return state_; }
render_tree::PixelFormat pixel_format() const { return pixel_format_; }
private:
// Called on construction to query the ResourceProvider for the best image
// pixel format to use.
void CalculatePixelFormat();
// |resource_provider_| is used to allocate render_tree::ImageData
render_tree::ResourceProvider* const resource_provider_;
// Decoded image data.
scoped_ptr<render_tree::ImageData> image_data_;
// |data_buffer_| is used to cache the undecoded data.
std::vector<uint8> data_buffer_;
// Record the current decoding status.
State state_;
// The pixel format that the decoded image data is expected to be in.
render_tree::PixelFormat pixel_format_;
};
} // namespace image
} // namespace loader
} // namespace cobalt
#endif // COBALT_LOADER_IMAGE_IMAGE_DATA_DECODER_H_