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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
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Add m-esr52 at 52.6.0
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diff --git a/gfx/layers/RotatedBuffer.h b/gfx/layers/RotatedBuffer.h
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+/* -*- 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_ */