gecko/gfx/layers/ImageLayers.h

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