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