gecko-dev/dom/canvas/ImageBitmapUtils.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef mozilla_dom_ImageBitmapUtils_h
#define mozilla_dom_ImageBitmapUtils_h
#include "mozilla/UniquePtr.h"
#include "nsTArrayForwardDeclare.h"
namespace mozilla {
namespace layers {
class Image;
struct PlanarYCbCrData;
}
namespace dom {
struct ChannelPixelLayout;
template<typename> class Sequence;
typedef nsTArray<ChannelPixelLayout> ImagePixelLayout;
/*
* This function creates an ImagePixelLayout object which describes the
* default layout of the given ImageBitmapFormat with the given width, height
* and stride.
*/
UniquePtr<ImagePixelLayout>
CreateDefaultPixelLayout(ImageBitmapFormat aFormat,
uint32_t aWidth, uint32_t aHeight, uint32_t aStride);
/*
* This function extracts information from the aImage parameter to customize
* the ImagePixelLayout object, that is, this function creates a customized
* ImagePixelLayout object which exactly describes the pixel layout of the
* given aImage.
*/
UniquePtr<ImagePixelLayout>
CreatePixelLayoutFromPlanarYCbCrData(const layers::PlanarYCbCrData* aData);
/*
* Get the number of channels of the given ImageBitmapFormat.
*/
uint8_t
GetChannelCountOfImageFormat(ImageBitmapFormat aFormat);
/*
* Get the needed buffer size to store the image data in the given
* ImageBitmapFormat with the given width and height.
*/
uint32_t
CalculateImageBufferSize(ImageBitmapFormat aFormat,
uint32_t aWidth, uint32_t aHeight);
/*
* This function always copies the image data in _aSrcBuffer_ into _aDstBuffer_
* and it also performs color conversion if the _aSrcFormat_ and the
* _aDstFormat_ are different.
*
* The source image is stored in the _aSrcBuffer_ and the corresponding pixel
* layout is described by the _aSrcLayout_.
*
* The copied and converted image will be stored in the _aDstBuffer_, which
* should be allocated with enough size before invoking this function and the
* needed size could be found by the CalculateImageBufferSize() method.
*
* The returned ImagePixelLayout object describes the pixel layout of the result
* image and will be null if on failure.
*/
UniquePtr<ImagePixelLayout>
CopyAndConvertImageData(ImageBitmapFormat aSrcFormat,
const uint8_t* aSrcBuffer,
const ImagePixelLayout* aSrcLayout,
ImageBitmapFormat aDstFormat,
uint8_t* aDstBuffer);
/*
* This function tries to find the best ImageBitmapFormat, from the aCandiates,
* which can be converted from the aSrcFormat. The algorithm now merely returns
* the FIRST one, from the aCandidates, which can be converted from the
* aSrcFormat.
*
* TODO: The algorithm should be updated after we implement optimizations for
* different platforms (different kinds of layers::Image), considering
* that some conversion might be cheaper through hardware.
*/
ImageBitmapFormat
FindBestMatchingFromat(ImageBitmapFormat aSrcFormat,
const Sequence<ImageBitmapFormat>& aCandidates);
} // namespace dom
} // namespace mozilla
#endif // mozilla_dom_ImageBitmapUtils_h