Bug 538323. Part 1: create ImageLayers and associated API for displaying pixel-buffers in various formats. r=jrmuizel,sr=dbaron
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Robert O'Callahan
272
gfx/layers/ImageLayers.h
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272
gfx/layers/ImageLayers.h
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/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is Mozilla Corporation code.
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*
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* The Initial Developer of the Original Code is Mozilla Foundation.
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* Portions created by the Initial Developer are Copyright (C) 2009
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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* Robert O'Callahan <robert@ocallahan.org>
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either the GNU General Public License Version 2 or later (the "GPL"), or
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* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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#ifndef GFX_IMAGELAYER_H
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#define GFX_IMAGELAYER_H
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#include "Layers.h"
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#include "gfxPattern.h"
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#include "nsThreadUtils.h"
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namespace mozilla {
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namespace layers {
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/**
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* A class representing a buffer of pixel data. The data can be in one
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* of various formats including YCbCr.
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*
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* Create an image using an ImageContainer. Fill the image with data, and
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* then call ImageContainer::SetImage to display it. An image must not be
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* modified after calling SetImage. Image implementations do not need to
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* perform locking; when filling an Image, the Image client is responsible
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* for ensuring only one thread accesses the Image at a time, and after
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* SetImage the image is immutable.
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*
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* When resampling an Image, only pixels within the buffer should be
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* sampled. For example, cairo images should be sampled in EXTEND_PAD mode.
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*/
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class THEBES_API Image {
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THEBES_INLINE_DECL_THREADSAFE_REFCOUNTING(Image)
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public:
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virtual ~Image() {}
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enum Format {
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/**
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* The PLANAR_YCBCR format creates a PlanarYCbCrImage. All backends should
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* support this format, because the Ogg video decoder depends on it.
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* The maximum image width and height is 16384.
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*/
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PLANAR_YCBCR,
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/**
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* The CAIRO_SURFACE format creates a CairoImage. All backends should
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* support this format, because video rendering sometimes requires it.
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*
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* This format is useful even though a ThebesLayer could be used.
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* It makes it easy to render a cairo surface when another Image format
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* could be used. It can also avoid copying the surface data in some
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* cases.
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*
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* Images in CAIRO_SURFACE format should only be created and
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* manipulated on the main thread, since the underlying cairo surface
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* is main-thread-only.
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*/
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CAIRO_SURFACE
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};
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Format GetFormat() { return mFormat; }
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void* GetImplData() { return mImplData; }
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protected:
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Image(void* aImplData, Format aFormat) :
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mImplData(aImplData),
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mFormat(aFormat)
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{}
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void* mImplData;
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Format mFormat;
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};
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/**
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* A class that manages Images for an ImageLayer. The only reason
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* we need a separate class here is that ImageLayers aren't threadsafe
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* (because layers can only be used on the main thread) and we want to
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* be able to set the current Image from any thread, to facilitate
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* video playback without involving the main thread, for example.
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*/
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class THEBES_API ImageContainer {
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THEBES_INLINE_DECL_THREADSAFE_REFCOUNTING(ImageContainer)
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public:
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virtual ~ImageContainer() {}
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/**
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* Create an Image in one of the given formats.
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* Picks the "best" format from the list and creates an Image of that
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* format.
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* Returns null if this backend does not support any of the formats.
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*/
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virtual already_AddRefed<Image> CreateImage(const Image::Format* aFormats,
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PRUint32 aNumFormats) = 0;
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/**
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* Set an Image as the current image to display. The Image must have
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* been created by this ImageContainer.
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*
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* The Image data must not be modified after this method is called!
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*/
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virtual void SetCurrentImage(Image* aImage) = 0;
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/**
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* Get the current Image.
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* This has to add a reference since otherwise there are race conditions
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* where the current image is destroyed before the caller can add
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* a reference.
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*/
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virtual already_AddRefed<Image> GetCurrentImage() = 0;
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/**
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* Get the current image as a gfxASurface. This is useful for fallback
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* rendering.
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* This can only be called from the main thread, since cairo objects
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* can only be used from the main thread.
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* This is defined here and not on Image because it's possible (likely)
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* that some backends will make an Image "ready to draw" only when it
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* becomes the current image for an image container.
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* Returns null if there is no current image.
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* Returns the size in aSize.
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* The returned surface will never be modified. The caller must not
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* modify it.
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*/
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virtual already_AddRefed<gfxASurface> GetCurrentAsSurface(gfxIntSize* aSizeResult) = 0;
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/**
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* Returns the layer manager for this container. This can only
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* be used on the main thread, since layer managers should only be
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* accessed on the main thread.
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*/
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LayerManager* Manager()
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{
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NS_PRECONDITION(NS_IsMainThread(), "Must be called on main thread");
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return mManager;
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}
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protected:
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LayerManager* mManager;
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ImageContainer(LayerManager* aManager) : mManager(aManager) {}
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};
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/**
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* A Layer which renders an Image.
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*/
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class THEBES_API ImageLayer : public Layer {
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public:
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/**
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* CONSTRUCTION PHASE ONLY
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* Set the ImageContainer. aContainer must have the same layer manager
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* as this layer.
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*/
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void SetContainer(ImageContainer* aContainer) { mContainer = aContainer; }
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/**
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* CONSTRUCTION PHASE ONLY
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* Set the filter used to resample this image if necessary.
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*/
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void SetFilter(gfxPattern::GraphicsFilter aFilter) { mFilter = aFilter; }
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ImageContainer* GetContainer() { return mContainer; }
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gfxPattern::GraphicsFilter GetFilter() { return mFilter; }
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protected:
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ImageLayer(LayerManager* aManager, void* aImplData)
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: Layer(aManager, aImplData), mFilter(gfxPattern::FILTER_GOOD) {}
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nsRefPtr<ImageContainer> mContainer;
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gfxPattern::GraphicsFilter mFilter;
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};
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/****** Image subtypes for the different formats ******/
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/**
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* We assume that the image data is in the REC 470M color space (see
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* Theora specification, section 4.3.1).
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* XXX Eventually we should some color space parameter(s) here.
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*/
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class THEBES_API PlanarYCbCrImage : public Image {
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public:
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struct Data {
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// Luminance buffer
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PRUint8* mYChannel;
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PRInt32 mYStride;
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gfxIntSize mYSize;
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// Chroma buffers
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PRUint8* mCbChannel;
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PRUint8* mCrChannel;
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PRInt32 mCbCrStride;
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gfxIntSize mCbCrSize;
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};
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typedef void (* ToARGBHook)(const Data& aData, PRUint8* aOutput);
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/**
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* XXX this is just a hack until we can get YCbCr conversion code into
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* gfx
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* This must be called before SetData().
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*/
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virtual void SetRGBConverter(ToARGBHook aHook) {}
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/**
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* This makes a copy of the data buffers.
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* XXX Eventually we will change this to not make a copy of the data,
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* but we can't do that until we have tighter control of nsOggDecoder's
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* buffer management (i.e. not going through liboggplay). Right now
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* it doesn't matter because the BasicLayer implementation does YCbCr
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* conversion here anyway.
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*/
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virtual void SetData(const Data& aData) = 0;
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protected:
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PlanarYCbCrImage(void* aImplData) : Image(aImplData, PLANAR_YCBCR) {}
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};
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/**
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* Currently, the data in a CairoImage surface is treated as being in the
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* device output color space.
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*/
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class THEBES_API CairoImage : public Image {
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public:
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struct Data {
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gfxASurface* mSurface;
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gfxIntSize mSize;
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};
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/**
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* This can only be called on the main thread. It may add a reference
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* to the surface (which will eventually be released on the main thread).
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* The surface must not be modified after this call!!!
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*/
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virtual void SetData(const Data& aData) = 0;
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protected:
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CairoImage(void* aImplData) : Image(aImplData, CAIRO_SURFACE) {}
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};
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}
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}
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#endif /* GFX_IMAGELAYER_H */
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