/* -*- 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_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 "gfxContext.h"                 // for gfxContext

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

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

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

#include "mozilla/TimeStamp.h"

#include "nsAString.h"

#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 nsIWidget;

namespace mozilla {

namespace layers {

class ImageFactory;

class ImageLayer;

class PaintLayerContext;

class ReadbackLayer;

/**

 * 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 PaintedLayer is painted directly into the target

 * context (with appropriate clipping and Push/PopGroups performed

 * between layers).

 */

class BasicLayerManager final :

    public LayerManager

{

public:

  enum BasicLayerManagerType {

    BLM_WIDGET,

    BLM_OFFSCREEN,

    BLM_INACTIVE

  };

  /**

   * Construct a BasicLayerManager which will have no default

   * target context. SetDefaultTarget or BeginTransactionWithTarget

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

   * be retained.

   */

  explicit BasicLayerManager(BasicLayerManagerType aType);

  /**

   * Construct a BasicLayerManager which will have no default

   * target context. SetDefaultTarget or BeginTransactionWithTarget

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

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

   * PaintedLayers as cairo surfaces. We create PaintedLayer 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.

   */

  explicit BasicLayerManager(nsIWidget* aWidget);

protected:

  virtual ~BasicLayerManager();

public:

  BasicLayerManager* AsBasicLayerManager() override { return this; }

  /**

   * 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 OP_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() override { return mWidget != nullptr; }

  virtual bool IsInactiveLayerManager() override { return mType == BLM_INACTIVE; }

  virtual bool BeginTransaction() override;

  virtual bool BeginTransactionWithTarget(gfxContext* aTarget) override;

  virtual bool EndEmptyTransaction(EndTransactionFlags aFlags = END_DEFAULT) override;

  virtual void EndTransaction(DrawPaintedLayerCallback aCallback,

                              void* aCallbackData,

                              EndTransactionFlags aFlags = END_DEFAULT) override;

  void AbortTransaction();

  virtual void SetRoot(Layer* aLayer) override;

  virtual already_AddRefed<PaintedLayer> CreatePaintedLayer() override;

  virtual already_AddRefed<ContainerLayer> CreateContainerLayer() override;

  virtual already_AddRefed<ImageLayer> CreateImageLayer() override;

  virtual already_AddRefed<CanvasLayer> CreateCanvasLayer() override;

  virtual already_AddRefed<ColorLayer> CreateColorLayer() override;

  virtual already_AddRefed<ReadbackLayer> CreateReadbackLayer() override;

  virtual ImageFactory *GetImageFactory();

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

  virtual void GetBackendName(nsAString& name) override { 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 override { return "Basic"; }

  // Clear the cached contents of this layer tree.

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

  void SetTransactionIncomplete() { mTransactionIncomplete = true; }

  bool IsTransactionIncomplete() { return mTransactionIncomplete; }

  struct PushedGroup

  {

    PushedGroup() : mFinalTarget(nullptr), mNeedsClipToVisibleRegion(false), mOperator(gfx::CompositionOp::OP_COUNT), mOpacity(0.0f){}

    gfxContext* mFinalTarget;

    RefPtr<gfxContext> mGroupTarget;

    nsIntRegion mVisibleRegion;

    bool mNeedsClipToVisibleRegion;

    gfx::IntPoint mGroupOffset;

    gfx::CompositionOp mOperator;

    gfx::Float mOpacity;

    RefPtr<gfx::SourceSurface> mMaskSurface;

    gfx::Matrix mMaskTransform;

  };

  // Construct a PushedGroup for a specific layer.

  // Return false if it has some errors in PushGroupForLayer(). Then, the

  // "aGroupResult" is unavailable for future using.

  bool PushGroupForLayer(gfxContext* aContext, Layer* aLayerContext, const nsIntRegion& aRegion, PushedGroup& aGroupResult);

  void PopGroupForLayer(PushedGroup& aGroup);

  virtual bool IsCompositingCheap() override { return false; }

  virtual int32_t GetMaxTextureSize() const override { return INT32_MAX; }

  bool CompositorMightResample() { return mCompositorMightResample; }

  TimeStamp GetCompositionTime() const

  {

    return mCompositionTime;

  }

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,

                  DrawPaintedLayerCallback aCallback,

                  void* aCallbackData);

  // Clear the contents of a layer

  void ClearLayer(Layer* aLayer);

  bool EndTransactionInternal(DrawPaintedLayerCallback aCallback,

                              void* aCallbackData,

                              EndTransactionFlags aFlags = END_DEFAULT);

  void FlashWidgetUpdateArea(gfxContext* aContext);

  void SetCompositionTime(TimeStamp aTimeStamp)

  {

    mCompositionTime = aTimeStamp;

  }

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

  // buffers.

  nsIWidget* mWidget;

  // The default context for BeginTransaction.

  RefPtr<gfxContext> mDefaultTarget;

  // The context to draw into.

  RefPtr<gfxContext> mTarget;

  // Image factory we use.

  RefPtr<ImageFactory> mFactory;

  BufferMode mDoubleBuffering;

  BasicLayerManagerType mType;

  bool mUsingDefaultTarget;

  bool mTransactionIncomplete;

  bool mCompositorMightResample;

  TimeStamp mCompositionTime;

};

} // namespace layers

} // namespace mozilla

#endif /* GFX_BASICLAYERS_H */