From 2aa4a82499d4becd2284cdb482213d541b8804dd Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 28 Apr 2024 16:29:10 +0200 Subject: Adding upstream version 86.0.1. Signed-off-by: Daniel Baumann --- gfx/layers/ReadbackLayer.h | 202 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 202 insertions(+) create mode 100644 gfx/layers/ReadbackLayer.h (limited to 'gfx/layers/ReadbackLayer.h') diff --git a/gfx/layers/ReadbackLayer.h b/gfx/layers/ReadbackLayer.h new file mode 100644 index 0000000000..3dde7d0ac7 --- /dev/null +++ b/gfx/layers/ReadbackLayer.h @@ -0,0 +1,202 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* 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 GFX_READBACKLAYER_H +#define GFX_READBACKLAYER_H + +#include // for uint64_t +#include "Layers.h" // for Layer, etc +#include "mozilla/gfx/Rect.h" // for gfxRect +#include "mozilla/gfx/Point.h" // for IntPoint +#include "mozilla/mozalloc.h" // for operator delete +#include "nsCOMPtr.h" // for already_AddRefed +#include "nsDebug.h" // for NS_ASSERTION +#include "nsPoint.h" // for nsIntPoint +#include "nscore.h" // for nsACString + +class gfxContext; + +namespace mozilla { +namespace layers { + +class ReadbackProcessor; + +namespace layerscope { +class LayersPacket; +} // namespace layerscope + +/** + * A ReadbackSink receives a stream of updates to a rectangle of pixels. + * These update callbacks are always called on the main thread, either during + * EndTransaction or from the event loop. + */ +class ReadbackSink { + public: + ReadbackSink() = default; + virtual ~ReadbackSink() = default; + + /** + * Sends an update to indicate that the background is currently unknown. + */ + virtual void SetUnknown(uint64_t aSequenceNumber) = 0; + /** + * Called by the layer system to indicate that the contents of part of + * the readback area are changing. + * @param aRect is the rectangle of content that is being updated, + * in the coordinate system of the ReadbackLayer. + * @param aSequenceNumber updates issued out of order should be ignored. + * Only use updates whose sequence counter is greater than all other updates + * seen so far. Return null when a non-fresh sequence value is given. + * @return a context into which the update should be drawn. This should be + * set up to clip to aRect. Zero should never be passed as a sequence number. + * If this returns null, EndUpdate should NOT be called. If it returns + * non-null, EndUpdate must be called. + * + * We don't support partially unknown backgrounds. Therefore, the + * first BeginUpdate after a SetUnknown will have the complete background. + */ + virtual already_AddRefed BeginUpdate( + const gfx::IntRect& aRect, uint64_t aSequenceNumber) = 0; + /** + * EndUpdate must be called immediately after BeginUpdate, without returning + * to the event loop. + * @param aContext the context returned by BeginUpdate + * Implicitly Restore()s the state of aContext. + */ + virtual void EndUpdate(const gfx::IntRect& aRect) = 0; +}; + +/** + * A ReadbackLayer never renders anything. It enables clients to extract + * the rendered contents of the layer tree below the ReadbackLayer. + * The rendered contents are delivered asynchronously via calls to a + * ReadbackSink object supplied by the client. + * + * This is a "best effort" API; it is possible for the layer system to tell + * the ReadbackSink that the contents of the readback area are unknown. + * + * This API exists to work around the limitations of transparent windowless + * plugin rendering APIs. It should not be used for anything else. + */ +class ReadbackLayer : public Layer { + public: + MOZ_LAYER_DECL_NAME("ReadbackLayer", TYPE_READBACK) + + virtual void ComputeEffectiveTransforms( + const gfx::Matrix4x4& aTransformToSurface) override { + // Snap our local transform first, and snap the inherited transform as well. + // This makes our snapping equivalent to what would happen if our content + // was drawn into a PaintedLayer (gfxContext would snap using the local + // transform, then we'd snap again when compositing the PaintedLayer). + mEffectiveTransform = + SnapTransform(GetLocalTransform(), + gfxRect(0, 0, mSize.width, mSize.height), nullptr) * + SnapTransformTranslation(aTransformToSurface, nullptr); + } + + /** + * CONSTRUCTION PHASE ONLY + * Set the callback object to which readback updates will be delivered. + * This also resets the "needed rectangle" so that on the next layer tree + * transaction we will try to deliver the full contents of the readback + * area to the sink. + * This layer takes ownership of the sink. It will be deleted when the + * layer is destroyed or when a new sink is set. + * Initially the contents of the readback area are completely unknown. + */ + void SetSink(ReadbackSink* aSink) { + SetUnknown(); + mSink = mozilla::WrapUnique(aSink); + } + ReadbackSink* GetSink() { return mSink.get(); } + + /** + * CONSTRUCTION PHASE ONLY + * Set the size of content that should be read back. The readback area + * has its top-left at 0,0 and has size aSize. + * Can only be called while the sink is null! + */ + void SetSize(const gfx::IntSize& aSize) { + NS_ASSERTION(!mSink, "Should have no sink while changing size!"); + mSize = aSize; + } + const gfx::IntSize& GetSize() { return mSize; } + gfx::IntRect GetRect() { return gfx::IntRect(gfx::IntPoint(0, 0), mSize); } + + bool IsBackgroundKnown() { + return mBackgroundLayer || mBackgroundColor.a == 1.f; + } + + void NotifyRemoved() { + SetUnknown(); + mSink = nullptr; + } + + void NotifyPaintedLayerRemoved(PaintedLayer* aLayer) { + if (mBackgroundLayer == aLayer) { + mBackgroundLayer = nullptr; + } + } + + const nsIntPoint& GetBackgroundLayerOffset() { + return mBackgroundLayerOffset; + } + + uint64_t AllocateSequenceNumber() { return ++mSequenceCounter; } + + void SetUnknown() { + if (IsBackgroundKnown()) { + if (mSink) { + mSink->SetUnknown(AllocateSequenceNumber()); + } + mBackgroundLayer = nullptr; + mBackgroundColor = gfx::DeviceColor(); + } + } + + protected: + friend class ReadbackProcessor; + + ReadbackLayer(LayerManager* aManager, void* aImplData) + : Layer(aManager, aImplData), + mSequenceCounter(0), + mSize(0, 0), + mBackgroundLayer(nullptr), + mBackgroundLayerOffset(0, 0), + mBackgroundColor(gfx::DeviceColor()) {} + + virtual void PrintInfo(std::stringstream& aStream, + const char* aPrefix) override; + + virtual void DumpPacket(layerscope::LayersPacket* aPacket, + const void* aParent) override; + + uint64_t mSequenceCounter; + UniquePtr mSink; + gfx::IntSize mSize; + + // This can refer to any (earlier) sibling PaintedLayer. That PaintedLayer + // must have mUsedForReadback set on it. If the PaintedLayer is removed + // for the container, this will be set to null by NotifyPaintedLayerRemoved. + // This PaintedLayer contains the contents which have previously been reported + // to mSink. The PaintedLayer had only an integer translation transform, + // and it covered the entire readback area. This layer also had only an + // integer translation transform. + PaintedLayer* mBackgroundLayer; + // When mBackgroundLayer is non-null, this is the offset to add to + // convert from the coordinates of mBackgroundLayer to the coordinates + // of this layer. + nsIntPoint mBackgroundLayerOffset; + // When mBackgroundColor is opaque, this is the color of the ColorLayer + // that contained the contents we reported to mSink, which covered the + // entire readback area. + gfx::DeviceColor mBackgroundColor; +}; + +} // namespace layers +} // namespace mozilla + +#endif /* GFX_READBACKLAYER_H */ -- cgit v1.2.3