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