431 lines
15 KiB
C++
431 lines
15 KiB
C++
/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef ROTATEDBUFFER_H_
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#define ROTATEDBUFFER_H_
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#include "gfxTypes.h"
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#include <stdint.h> // for uint32_t
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#include "mozilla/Assertions.h" // for MOZ_ASSERT, etc
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#include "mozilla/RefPtr.h" // for RefPtr, already_AddRefed
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#include "mozilla/gfx/2D.h" // for DrawTarget, etc
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#include "mozilla/mozalloc.h" // for operator delete
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#include "nsCOMPtr.h" // for already_AddRefed
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#include "nsDebug.h" // for NS_RUNTIMEABORT
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#include "nsISupportsImpl.h" // for MOZ_COUNT_CTOR, etc
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#include "nsRegion.h" // for nsIntRegion
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#include "LayersTypes.h"
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namespace mozilla {
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namespace gfx {
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class Matrix;
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} // namespace gfx
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namespace layers {
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class TextureClient;
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class PaintedLayer;
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/**
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* This is a cairo/Thebes surface, but with a literal twist. Scrolling
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* causes the layer's visible region to move. We want to keep
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* reusing the same surface if the region size hasn't changed, but we don't
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* want to keep moving the contents of the surface around in memory. So
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* we use a trick.
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* Consider just the vertical case, and suppose the buffer is H pixels
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* high and we're scrolling down by N pixels. Instead of copying the
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* buffer contents up by N pixels, we leave the buffer contents in place,
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* and paint content rows H to H+N-1 into rows 0 to N-1 of the buffer.
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* Then we can refresh the screen by painting rows N to H-1 of the buffer
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* at row 0 on the screen, and then painting rows 0 to N-1 of the buffer
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* at row H-N on the screen.
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* mBufferRotation.y would be N in this example.
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*/
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class RotatedBuffer {
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public:
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typedef gfxContentType ContentType;
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RotatedBuffer(const gfx::IntRect& aBufferRect,
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const gfx::IntPoint& aBufferRotation)
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: mBufferRect(aBufferRect)
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, mBufferRotation(aBufferRotation)
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, mDidSelfCopy(false)
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{ }
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RotatedBuffer()
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: mDidSelfCopy(false)
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{ }
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/*
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* Which buffer should be drawn to/read from.
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*/
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enum ContextSource {
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BUFFER_BLACK, // The normal buffer, or buffer with black background when using component alpha.
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BUFFER_WHITE, // The buffer with white background, only valid with component alpha.
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BUFFER_BOTH // The combined black/white buffers, only valid for writing operations, not reading.
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};
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// It is the callers repsonsibility to ensure aTarget is flushed after calling
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// this method.
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void DrawBufferWithRotation(gfx::DrawTarget* aTarget, ContextSource aSource,
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float aOpacity = 1.0,
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gfx::CompositionOp aOperator = gfx::CompositionOp::OP_OVER,
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gfx::SourceSurface* aMask = nullptr,
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const gfx::Matrix* aMaskTransform = nullptr) const;
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/**
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* |BufferRect()| is the rect of device pixels that this
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* RotatedBuffer covers. That is what DrawBufferWithRotation()
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* will paint when it's called.
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*/
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const gfx::IntRect& BufferRect() const { return mBufferRect; }
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const gfx::IntPoint& BufferRotation() const { return mBufferRotation; }
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virtual bool HaveBuffer() const = 0;
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virtual bool HaveBufferOnWhite() const = 0;
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virtual already_AddRefed<gfx::SourceSurface> GetSourceSurface(ContextSource aSource) const = 0;
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protected:
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enum XSide {
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LEFT, RIGHT
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};
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enum YSide {
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TOP, BOTTOM
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};
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gfx::IntRect GetQuadrantRectangle(XSide aXSide, YSide aYSide) const;
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gfx::Rect GetSourceRectangle(XSide aXSide, YSide aYSide) const;
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/*
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* If aMask is non-null, then it is used as an alpha mask for rendering this
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* buffer. aMaskTransform must be non-null if aMask is non-null, and is used
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* to adjust the coordinate space of the mask.
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*/
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void DrawBufferQuadrant(gfx::DrawTarget* aTarget, XSide aXSide, YSide aYSide,
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ContextSource aSource,
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float aOpacity,
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gfx::CompositionOp aOperator,
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gfx::SourceSurface* aMask,
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const gfx::Matrix* aMaskTransform) const;
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/** The area of the PaintedLayer that is covered by the buffer as a whole */
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gfx::IntRect mBufferRect;
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/**
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* The x and y rotation of the buffer. Conceptually the buffer
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* has its origin translated to mBufferRect.TopLeft() - mBufferRotation,
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* is tiled to fill the plane, and the result is clipped to mBufferRect.
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* So the pixel at mBufferRotation within the buffer is what gets painted at
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* mBufferRect.TopLeft().
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* This is "rotation" in the sense of rotating items in a linear buffer,
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* where items falling off the end of the buffer are returned to the
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* buffer at the other end, not 2D rotation!
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*/
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gfx::IntPoint mBufferRotation;
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// When this is true it means that all pixels have moved inside the buffer.
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// It's not possible to sync with another buffer without a full copy.
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bool mDidSelfCopy;
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};
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class SourceRotatedBuffer : public RotatedBuffer
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{
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public:
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SourceRotatedBuffer(gfx::SourceSurface* aSource, gfx::SourceSurface* aSourceOnWhite,
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const gfx::IntRect& aBufferRect,
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const gfx::IntPoint& aBufferRotation)
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: RotatedBuffer(aBufferRect, aBufferRotation)
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, mSource(aSource)
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, mSourceOnWhite(aSourceOnWhite)
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{ }
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virtual already_AddRefed<gfx::SourceSurface> GetSourceSurface(ContextSource aSource) const;
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virtual bool HaveBuffer() const { return !!mSource; }
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virtual bool HaveBufferOnWhite() const { return !!mSourceOnWhite; }
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private:
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RefPtr<gfx::SourceSurface> mSource;
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RefPtr<gfx::SourceSurface> mSourceOnWhite;
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};
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// Mixin class for classes which need logic for loaning out a draw target.
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// See comments on BorrowDrawTargetForQuadrantUpdate.
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class BorrowDrawTarget
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{
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protected:
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void ReturnDrawTarget(gfx::DrawTarget*& aReturned);
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// The draw target loaned by BorrowDrawTargetForQuadrantUpdate. It should not
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// be used, we just keep a reference to ensure it is kept alive and so we can
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// correctly restore state when it is returned.
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RefPtr<gfx::DrawTarget> mLoanedDrawTarget;
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gfx::Matrix mLoanedTransform;
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};
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/**
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* This class encapsulates the buffer used to retain PaintedLayer contents,
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* i.e., the contents of the layer's GetVisibleRegion().
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*/
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class RotatedContentBuffer : public RotatedBuffer
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, public BorrowDrawTarget
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{
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public:
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typedef gfxContentType ContentType;
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/**
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* Controls the size of the backing buffer of this.
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* - SizedToVisibleBounds: the backing buffer is exactly the same
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* size as the bounds of PaintedLayer's visible region
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* - ContainsVisibleBounds: the backing buffer is large enough to
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* fit visible bounds. May be larger.
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*/
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enum BufferSizePolicy {
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SizedToVisibleBounds,
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ContainsVisibleBounds
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};
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explicit RotatedContentBuffer(BufferSizePolicy aBufferSizePolicy)
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: mBufferProvider(nullptr)
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, mBufferProviderOnWhite(nullptr)
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, mBufferSizePolicy(aBufferSizePolicy)
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{
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MOZ_COUNT_CTOR(RotatedContentBuffer);
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}
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virtual ~RotatedContentBuffer()
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{
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MOZ_COUNT_DTOR(RotatedContentBuffer);
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}
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/**
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* Wipe out all retained contents. Call this when the entire
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* buffer becomes invalid.
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*/
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void Clear()
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{
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mDTBuffer = nullptr;
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mDTBufferOnWhite = nullptr;
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mBufferProvider = nullptr;
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mBufferProviderOnWhite = nullptr;
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mBufferRect.SetEmpty();
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}
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/**
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* This is returned by BeginPaint. The caller should draw into mTarget.
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* mRegionToDraw must be drawn. mRegionToInvalidate has been invalidated
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* by RotatedContentBuffer and must be redrawn on the screen.
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* mRegionToInvalidate is set when the buffer has changed from
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* opaque to transparent or vice versa, since the details of rendering can
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* depend on the buffer type. mDidSelfCopy is true if we kept our buffer
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* but used MovePixels() to shift its content.
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*/
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struct PaintState {
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PaintState()
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: mRegionToDraw()
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, mRegionToInvalidate()
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, mMode(SurfaceMode::SURFACE_NONE)
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, mClip(DrawRegionClip::NONE)
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, mContentType(gfxContentType::SENTINEL)
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, mDidSelfCopy(false)
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{}
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nsIntRegion mRegionToDraw;
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nsIntRegion mRegionToInvalidate;
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SurfaceMode mMode;
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DrawRegionClip mClip;
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ContentType mContentType;
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bool mDidSelfCopy;
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};
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enum {
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PAINT_WILL_RESAMPLE = 0x01,
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PAINT_NO_ROTATION = 0x02,
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PAINT_CAN_DRAW_ROTATED = 0x04
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};
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/**
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* Start a drawing operation. This returns a PaintState describing what
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* needs to be drawn to bring the buffer up to date in the visible region.
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* This queries aLayer to get the currently valid and visible regions.
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* The returned mTarget may be null if mRegionToDraw is empty.
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* Otherwise it must not be null.
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* mRegionToInvalidate will contain mRegionToDraw.
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* @param aFlags when PAINT_WILL_RESAMPLE is passed, this indicates that
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* buffer will be resampled when rendering (i.e the effective transform
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* combined with the scale for the resolution is not just an integer
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* translation). This will disable buffer rotation (since we don't want
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* to resample across the rotation boundary) and will ensure that we
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* make the entire buffer contents valid (since we don't want to sample
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* invalid pixels outside the visible region, if the visible region doesn't
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* fill the buffer bounds).
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* PAINT_CAN_DRAW_ROTATED can be passed if the caller supports drawing
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* rotated content that crosses the physical buffer boundary. The caller
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* will need to call BorrowDrawTargetForPainting multiple times to achieve
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* this.
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*/
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PaintState BeginPaint(PaintedLayer* aLayer,
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uint32_t aFlags);
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struct DrawIterator {
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friend class RotatedContentBuffer;
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DrawIterator()
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: mCount(0)
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{}
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nsIntRegion mDrawRegion;
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private:
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uint32_t mCount;
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};
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/**
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* Fetch a DrawTarget for rendering. The DrawTarget remains owned by
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* this. See notes on BorrowDrawTargetForQuadrantUpdate.
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* May return null. If the return value is non-null, it must be
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* 'un-borrowed' using ReturnDrawTarget.
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*
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* If PAINT_CAN_DRAW_ROTATED was specified for BeginPaint, then the caller
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* must call this function repeatedly (with an iterator) until it returns
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* nullptr. The caller should draw the mDrawRegion of the iterator instead
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* of mRegionToDraw in the PaintState.
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*
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* @param aPaintState Paint state data returned by a call to BeginPaint
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* @param aIter Paint state iterator. Only required if PAINT_CAN_DRAW_ROTATED
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* was specified to BeginPaint.
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*/
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gfx::DrawTarget* BorrowDrawTargetForPainting(PaintState& aPaintState,
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DrawIterator* aIter = nullptr);
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enum {
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BUFFER_COMPONENT_ALPHA = 0x02 // Dual buffers should be created for drawing with
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// component alpha.
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};
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/**
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* Return a new surface of |aSize| and |aType|.
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*
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* If the created buffer supports azure content, then the result(s) will
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* be returned in aBlackDT/aWhiteDT, otherwise aBlackSurface/aWhiteSurface
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* will be used.
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*/
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virtual void
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CreateBuffer(ContentType aType, const gfx::IntRect& aRect, uint32_t aFlags,
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RefPtr<gfx::DrawTarget>* aBlackDT, RefPtr<gfx::DrawTarget>* aWhiteDT) = 0;
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/**
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* Get the underlying buffer, if any. This is useful because we can pass
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* in the buffer as the default "reference surface" if there is one.
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* Don't use it for anything else!
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*/
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gfx::DrawTarget* GetDTBuffer() { return mDTBuffer; }
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gfx::DrawTarget* GetDTBufferOnWhite() { return mDTBufferOnWhite; }
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virtual already_AddRefed<gfx::SourceSurface> GetSourceSurface(ContextSource aSource) const;
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/**
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* Complete the drawing operation. The region to draw must have been
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* drawn before this is called. The contents of the buffer are drawn
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* to aTarget.
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*/
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void DrawTo(PaintedLayer* aLayer,
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gfx::DrawTarget* aTarget,
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float aOpacity,
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gfx::CompositionOp aOp,
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gfx::SourceSurface* aMask,
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const gfx::Matrix* aMaskTransform);
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protected:
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// new texture client versions
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void SetBufferProvider(TextureClient* aClient)
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{
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// Only this buffer provider can give us a buffer. If we
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// already have one, something has gone wrong.
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MOZ_ASSERT(!aClient || !mDTBuffer || !mDTBuffer->IsValid());
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mBufferProvider = aClient;
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if (!mBufferProvider) {
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mDTBuffer = nullptr;
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}
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}
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void SetBufferProviderOnWhite(TextureClient* aClient)
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{
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// Only this buffer provider can give us a buffer. If we
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// already have one, something has gone wrong.
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MOZ_ASSERT(!aClient || !mDTBufferOnWhite || !mDTBufferOnWhite->IsValid());
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mBufferProviderOnWhite = aClient;
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if (!mBufferProviderOnWhite) {
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mDTBufferOnWhite = nullptr;
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}
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}
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/**
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* Get a draw target at the specified resolution for updating |aBounds|,
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* which must be contained within a single quadrant.
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*
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* The result should only be held temporarily by the caller (it will be kept
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* alive by this). Once used it should be returned using ReturnDrawTarget.
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* BorrowDrawTargetForQuadrantUpdate may not be called more than once without
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* first calling ReturnDrawTarget.
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*
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* ReturnDrawTarget will restore the transform on the draw target. But it is
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* the callers responsibility to restore the clip. The caller should flush the
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* draw target, if necessary.
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*/
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gfx::DrawTarget*
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BorrowDrawTargetForQuadrantUpdate(const gfx::IntRect& aBounds,
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ContextSource aSource,
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DrawIterator* aIter);
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static bool IsClippingCheap(gfx::DrawTarget* aTarget, const nsIntRegion& aRegion);
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protected:
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/**
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* Return the buffer's content type. Requires a valid buffer or
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* buffer provider.
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*/
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gfxContentType BufferContentType();
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bool BufferSizeOkFor(const gfx::IntSize& aSize);
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/**
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* If the buffer hasn't been mapped, map it.
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*/
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bool EnsureBuffer();
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bool EnsureBufferOnWhite();
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// Flush our buffers if they are mapped.
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void FlushBuffers();
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/**
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* True if we have a buffer where we can get it (but not necessarily
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* mapped currently).
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*/
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virtual bool HaveBuffer() const;
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virtual bool HaveBufferOnWhite() const;
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/**
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* Any actions that should be performed at the last moment before we begin
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* rendering the next frame. I.e., after we calculate what we will draw,
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* but before we rotate the buffer and possibly create new buffers.
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* aRegionToDraw is the region which is guaranteed to be overwritten when
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* drawing the next frame.
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*/
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virtual void FinalizeFrame(const nsIntRegion& aRegionToDraw) {}
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RefPtr<gfx::DrawTarget> mDTBuffer;
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RefPtr<gfx::DrawTarget> mDTBufferOnWhite;
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/**
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* These members are only set transiently. They're used to map mDTBuffer
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* when we're using surfaces that require explicit map/unmap. Only one
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* may be used at a time.
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*/
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TextureClient* mBufferProvider;
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TextureClient* mBufferProviderOnWhite;
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BufferSizePolicy mBufferSizePolicy;
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};
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} // namespace layers
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} // namespace mozilla
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#endif /* ROTATEDBUFFER_H_ */
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