The Tor Browser / file revision

 /* -*- Mode: C++; tab-width: 2; 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 GFX_BASICLAYERS_H

 #define GFX_BASICLAYERS_H

 #include <stdint.h>                     // for INT32_MAX, int32_t

 #include "Layers.h"                     // for Layer (ptr only), etc

 #include "gfxTypes.h"

 #include "gfxCachedTempSurface.h"       // for gfxCachedTempSurface

 #include "gfxContext.h"                 // for gfxContext

 #include "mozilla/Attributes.h"         // for MOZ_OVERRIDE

 #include "mozilla/WidgetUtils.h"        // for ScreenRotation

 #include "mozilla/layers/LayersTypes.h"  // for BufferMode, LayersBackend, etc

 #include "nsAString.h"

 #include "nsAutoPtr.h"                  // for nsRefPtr

 #include "nsCOMPtr.h"                   // for already_AddRefed

 #include "nsISupportsImpl.h"            // for gfxContext::AddRef, etc

 #include "nsRegion.h"                   // for nsIntRegion

 #include "nscore.h"                     // for nsAString, etc

 class gfxPattern;

 class nsIWidget;

 namespace mozilla {

 namespace layers {

 class BasicShadowableLayer;

 class ImageFactory;

 class ImageLayer;

 class PaintLayerContext;

 class ReadbackLayer;

 class ReadbackProcessor;

 /**

  * This is a cairo/Thebes-only, main-thread-only implementation of layers.

  * 

  * In each transaction, the client sets up the layer tree and then during

  * the drawing phase, each ThebesLayer is painted directly into the target

  * context (with appropriate clipping and Push/PopGroups performed

  * between layers).

  */

 class BasicLayerManager :

     public LayerManager

 {

 public:

   /**

    * Construct a BasicLayerManager which will have no default

    * target context. SetDefaultTarget or BeginTransactionWithTarget

    * must be called for any rendering to happen. ThebesLayers will not

    * be retained.

    */

   BasicLayerManager();

   /**

    * Construct a BasicLayerManager which will have no default

    * target context. SetDefaultTarget or BeginTransactionWithTarget

    * must be called for any rendering to happen. ThebesLayers will be

    * retained; that is, we will try to retain the visible contents of

    * ThebesLayers as cairo surfaces. We create ThebesLayer buffers by

    * creating similar surfaces to the default target context, or to

    * aWidget's GetThebesSurface if there is no default target context, or

    * to the passed-in context if there is no widget and no default

    * target context.

    * 

    * This does not keep a strong reference to the widget, so the caller

    * must ensure that the widget outlives the layer manager or call

    * ClearWidget before the widget dies.

    */

   BasicLayerManager(nsIWidget* aWidget);

   virtual ~BasicLayerManager();

   /**

    * Set the default target context that will be used when BeginTransaction

    * is called. This can only be called outside a transaction.

    * 

    * aDoubleBuffering can request double-buffering for drawing to the

    * default target. When BUFFERED, the layer manager avoids blitting

    * temporary results to aContext and then overpainting them with final

    * results, by using a temporary buffer when necessary. In BUFFERED

    * mode we always completely overwrite the contents of aContext's

    * destination surface (within the clip region) using OPERATOR_SOURCE.

    */

   void SetDefaultTarget(gfxContext* aContext);

   virtual void SetDefaultTargetConfiguration(BufferMode aDoubleBuffering, ScreenRotation aRotation);

   gfxContext* GetDefaultTarget() { return mDefaultTarget; }

   nsIWidget* GetRetainerWidget() { return mWidget; }

   void ClearRetainerWidget() { mWidget = nullptr; }

   virtual bool IsWidgetLayerManager() { return mWidget != nullptr; }

   virtual void BeginTransaction();

   virtual void BeginTransactionWithTarget(gfxContext* aTarget);

   virtual bool EndEmptyTransaction(EndTransactionFlags aFlags = END_DEFAULT);

   virtual void EndTransaction(DrawThebesLayerCallback aCallback,

                               void* aCallbackData,

                               EndTransactionFlags aFlags = END_DEFAULT);

   virtual bool AreComponentAlphaLayersEnabled() { return !IsWidgetLayerManager(); }

   void AbortTransaction();

   virtual void SetRoot(Layer* aLayer);

   virtual already_AddRefed<ThebesLayer> CreateThebesLayer();

   virtual already_AddRefed<ContainerLayer> CreateContainerLayer();

   virtual already_AddRefed<ImageLayer> CreateImageLayer();

   virtual already_AddRefed<CanvasLayer> CreateCanvasLayer();

   virtual already_AddRefed<ColorLayer> CreateColorLayer();

   virtual already_AddRefed<ReadbackLayer> CreateReadbackLayer();

   virtual ImageFactory *GetImageFactory();

   virtual LayersBackend GetBackendType() { return LayersBackend::LAYERS_BASIC; }

   virtual void GetBackendName(nsAString& name) { name.AssignLiteral("Basic"); }

   bool InConstruction() { return mPhase == PHASE_CONSTRUCTION; }

 #ifdef DEBUG

   bool InDrawing() { return mPhase == PHASE_DRAWING; }

   bool InForward() { return mPhase == PHASE_FORWARD; }

 #endif

   bool InTransaction() { return mPhase != PHASE_NONE; }

   gfxContext* GetTarget() { return mTarget; }

   void SetTarget(gfxContext* aTarget) { mUsingDefaultTarget = false; mTarget = aTarget; }

   bool IsRetained() { return mWidget != nullptr; }

   virtual const char* Name() const { return "Basic"; }

   // Clear the cached contents of this layer tree.

   virtual void ClearCachedResources(Layer* aSubtree = nullptr) MOZ_OVERRIDE;

   void SetTransactionIncomplete() { mTransactionIncomplete = true; }

   bool IsTransactionIncomplete() { return mTransactionIncomplete; }

   already_AddRefed<gfxContext> PushGroupForLayer(gfxContext* aContext, Layer* aLayer,

                                                  const nsIntRegion& aRegion,

                                                  bool* aNeedsClipToVisibleRegion);

   already_AddRefed<gfxContext> PushGroupWithCachedSurface(gfxContext *aTarget,

                                                           gfxContentType aContent);

   void PopGroupToSourceWithCachedSurface(gfxContext *aTarget, gfxContext *aPushed);

   virtual bool IsCompositingCheap() { return false; }

   virtual int32_t GetMaxTextureSize() const { return INT32_MAX; }

   bool CompositorMightResample() { return mCompositorMightResample; }

 protected:

   enum TransactionPhase {

     PHASE_NONE, PHASE_CONSTRUCTION, PHASE_DRAWING, PHASE_FORWARD

   };

   TransactionPhase mPhase;

   // This is the main body of the PaintLayer routine which will if it has

   // children, recurse into PaintLayer() otherwise it will paint using the

   // underlying Paint() method of the Layer. It will not do both.

   void PaintSelfOrChildren(PaintLayerContext& aPaintContext, gfxContext* aGroupTarget);

   // Paint the group onto the underlying target. This is used by PaintLayer to

   // flush the group to the underlying target.

   void FlushGroup(PaintLayerContext& aPaintContext, bool aNeedsClipToVisibleRegion);

   // Paints aLayer to mTarget.

   void PaintLayer(gfxContext* aTarget,

                   Layer* aLayer,

                   DrawThebesLayerCallback aCallback,

                   void* aCallbackData,

                   ReadbackProcessor* aReadback);

   // Clear the contents of a layer

   void ClearLayer(Layer* aLayer);

   bool EndTransactionInternal(DrawThebesLayerCallback aCallback,

                               void* aCallbackData,

                               EndTransactionFlags aFlags = END_DEFAULT);

   void FlashWidgetUpdateArea(gfxContext* aContext);

   void RenderDebugOverlay();

   // Widget whose surface should be used as the basis for ThebesLayer

   // buffers.

   nsIWidget* mWidget;

   // The default context for BeginTransaction.

   nsRefPtr<gfxContext> mDefaultTarget;

   // The context to draw into.

   nsRefPtr<gfxContext> mTarget;

   // Image factory we use.

   nsRefPtr<ImageFactory> mFactory;

   // Cached surface for double buffering

   gfxCachedTempSurface mCachedSurface;

   BufferMode mDoubleBuffering;

   bool mUsingDefaultTarget;

   bool mCachedSurfaceInUse;

   bool mTransactionIncomplete;

   bool mCompositorMightResample;

 };

 }

 }

 #endif /* GFX_BASICLAYERS_H */