dom/smil/nsSMILCompositor.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef NS_SMILCOMPOSITOR_H_
   7 #define NS_SMILCOMPOSITOR_H_
   8
   9 #include "mozilla/Move.h"
  10 #include "nsTHashtable.h"
  11 #include "nsString.h"
  12 #include "nsSMILAnimationFunction.h"
  13 #include "nsSMILTargetIdentifier.h"
  14 #include "nsSMILCompositorTable.h"
  15 #include "pldhash.h"
  16
  17 //----------------------------------------------------------------------
  18 // nsSMILCompositor
  19 //
  20 // Performs the composition of the animation sandwich by combining the results
  21 // of a series animation functions according to the rules of SMIL composition
  22 // including prioritising animations.
  23
  24 class nsSMILCompositor : public PLDHashEntryHdr
  25 {
  26 public:
  27   typedef nsSMILTargetIdentifier KeyType;
  28   typedef const KeyType& KeyTypeRef;
  29   typedef const KeyType* KeyTypePointer;
  30
  31   explicit nsSMILCompositor(KeyTypePointer aKey)
  32    : mKey(*aKey),
  33      mForceCompositing(false)
  34   { }
  35   nsSMILCompositor(const nsSMILCompositor& toCopy)
  36     : mKey(toCopy.mKey),
  37       mAnimationFunctions(toCopy.mAnimationFunctions),
  38       mForceCompositing(false)
  39   { }
  40   ~nsSMILCompositor() { }
  41
  42   // PLDHashEntryHdr methods
  43   KeyTypeRef GetKey() const { return mKey; }
  44   bool KeyEquals(KeyTypePointer aKey) const;
  45   static KeyTypePointer KeyToPointer(KeyTypeRef aKey) { return &aKey; }
  46   static PLDHashNumber HashKey(KeyTypePointer aKey);
  47   enum { ALLOW_MEMMOVE = false };
  48
  49   // Adds the given animation function to this Compositor's list of functions
  50   void AddAnimationFunction(nsSMILAnimationFunction* aFunc);
  51
  52   // Composes the attribute's current value with the list of animation
  53   // functions, and assigns the resulting value to this compositor's target
  54   // attribute
  55   void ComposeAttribute();
  56
  57   // Clears animation effects on my target attribute
  58   void ClearAnimationEffects();
  59
  60   // Cycle-collection support
  61   void Traverse(nsCycleCollectionTraversalCallback* aCallback);
  62
  63   // Toggles a bit that will force us to composite (bypassing early-return
  64   // optimizations) when we hit ComposeAttribute.
  65   void ToggleForceCompositing() { mForceCompositing = true; }
  66
  67   // Transfers |aOther|'s mCachedBaseValue to |this|
  68   void StealCachedBaseValue(nsSMILCompositor* aOther) {
  69     mCachedBaseValue = mozilla::Move(aOther->mCachedBaseValue);
  70   }
  71
  72  private:
  73   // Create a nsISMILAttr for my target, on the heap.  Caller is responsible
  74   // for deallocating the returned object.
  75   nsISMILAttr* CreateSMILAttr();
  76
  77   // Finds the index of the first function that will affect our animation
  78   // sandwich. Also toggles the 'mForceCompositing' flag if it finds that any
  79   // (used) functions have changed.
  80   uint32_t GetFirstFuncToAffectSandwich();
  81
  82   // If the passed-in base value differs from our cached base value, this
  83   // method updates the cached value (and toggles the 'mForceCompositing' flag)
  84   void UpdateCachedBaseValue(const nsSMILValue& aBaseValue);
  85
  86   // Static callback methods
  87   static PLDHashOperator DoComposeAttribute(
  88       nsSMILCompositor* aCompositor, void *aData);
  89
  90   // The hash key (tuple of element/attributeName/attributeType)
  91   KeyType mKey;
  92
  93   // Hash Value: List of animation functions that animate the specified attr
  94   nsTArray<nsSMILAnimationFunction*> mAnimationFunctions;
  95
  96   // Member data for detecting when we need to force-recompose
  97   // ---------------------------------------------------------
  98   // Flag for tracking whether we need to compose. Initialized to false, but
  99   // gets flipped to true if we detect that something has changed.
 100   bool mForceCompositing;
 101
 102   // Cached base value, so we can detect & force-recompose when it changes
 103   // from one sample to the next. (nsSMILAnimationController copies this
 104   // forward from the previous sample's compositor.)
 105   nsAutoPtr<nsSMILValue> mCachedBaseValue;
 106 };
 107
 108 #endif // NS_SMILCOMPOSITOR_H_