dom/smil/nsSMILCompositor.cpp

   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 #include "nsSMILCompositor.h"
   7 #include "nsSMILCSSProperty.h"
   8 #include "nsCSSProps.h"
   9 #include "nsHashKeys.h"
  10
  11 // PLDHashEntryHdr methods
  12 bool
  13 nsSMILCompositor::KeyEquals(KeyTypePointer aKey) const
  14 {
  15   return aKey && aKey->Equals(mKey);
  16 }
  17
  18 /*static*/ PLDHashNumber
  19 nsSMILCompositor::HashKey(KeyTypePointer aKey)
  20 {
  21   // Combine the 3 values into one numeric value, which will be hashed.
  22   // NOTE: We right-shift one of the pointers by 2 to get some randomness in
  23   // its 2 lowest-order bits. (Those shifted-off bits will always be 0 since
  24   // our pointers will be word-aligned.)
  25   return (NS_PTR_TO_UINT32(aKey->mElement.get()) >> 2) +
  26     NS_PTR_TO_UINT32(aKey->mAttributeName.get()) +
  27     (aKey->mIsCSS ? 1 : 0);
  28 }
  29
  30 // Cycle-collection support
  31 void
  32 nsSMILCompositor::Traverse(nsCycleCollectionTraversalCallback* aCallback)
  33 {
  34   if (!mKey.mElement)
  35     return;
  36
  37   NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(*aCallback, "Compositor mKey.mElement");
  38   aCallback->NoteXPCOMChild(mKey.mElement);
  39 }
  40
  41 // Other methods
  42 void
  43 nsSMILCompositor::AddAnimationFunction(nsSMILAnimationFunction* aFunc)
  44 {
  45   if (aFunc) {
  46     mAnimationFunctions.AppendElement(aFunc);
  47   }
  48 }
  49
  50 void
  51 nsSMILCompositor::ComposeAttribute()
  52 {
  53   if (!mKey.mElement)
  54     return;
  55
  56   // FIRST: Get the nsISMILAttr (to grab base value from, and to eventually
  57   // give animated value to)
  58   nsAutoPtr<nsISMILAttr> smilAttr(CreateSMILAttr());
  59   if (!smilAttr) {
  60     // Target attribute not found (or, out of memory)
  61     return;
  62   }
  63   if (mAnimationFunctions.IsEmpty()) {
  64     // No active animation functions. (We can still have a nsSMILCompositor in
  65     // that case if an animation function has *just* become inactive)
  66     smilAttr->ClearAnimValue();
  67     return;
  68   }
  69
  70   // SECOND: Sort the animationFunctions, to prepare for compositing.
  71   nsSMILAnimationFunction::Comparator comparator;
  72   mAnimationFunctions.Sort(comparator);
  73
  74   // THIRD: Step backwards through animation functions to find out
  75   // which ones we actually care about.
  76   uint32_t firstFuncToCompose = GetFirstFuncToAffectSandwich();
  77
  78   // FOURTH: Get & cache base value
  79   nsSMILValue sandwichResultValue;
  80   if (!mAnimationFunctions[firstFuncToCompose]->WillReplace()) {
  81     sandwichResultValue = smilAttr->GetBaseValue();
  82   }
  83   UpdateCachedBaseValue(sandwichResultValue);
  84
  85   if (!mForceCompositing) {
  86     return;
  87   }
  88
  89   // FIFTH: Compose animation functions
  90   uint32_t length = mAnimationFunctions.Length();
  91   for (uint32_t i = firstFuncToCompose; i < length; ++i) {
  92     mAnimationFunctions[i]->ComposeResult(*smilAttr, sandwichResultValue);
  93   }
  94   if (sandwichResultValue.IsNull()) {
  95     smilAttr->ClearAnimValue();
  96     return;
  97   }
  98
  99   // SIXTH: Set the animated value to the final composited result.
 100   nsresult rv = smilAttr->SetAnimValue(sandwichResultValue);
 101   if (NS_FAILED(rv)) {
 102     NS_WARNING("nsISMILAttr::SetAnimValue failed");
 103   }
 104 }
 105
 106 void
 107 nsSMILCompositor::ClearAnimationEffects()
 108 {
 109   if (!mKey.mElement || !mKey.mAttributeName)
 110     return;
 111
 112   nsAutoPtr<nsISMILAttr> smilAttr(CreateSMILAttr());
 113   if (!smilAttr) {
 114     // Target attribute not found (or, out of memory)
 115     return;
 116   }
 117   smilAttr->ClearAnimValue();
 118 }
 119
 120 // Protected Helper Functions
 121 // --------------------------
 122 nsISMILAttr*
 123 nsSMILCompositor::CreateSMILAttr()
 124 {
 125   if (mKey.mIsCSS) {
 126     nsCSSProperty propId =
 127       nsCSSProps::LookupProperty(nsDependentAtomString(mKey.mAttributeName),
 128                                  nsCSSProps::eEnabledForAllContent);
 129     if (nsSMILCSSProperty::IsPropertyAnimatable(propId)) {
 130       return new nsSMILCSSProperty(propId, mKey.mElement.get());
 131     }
 132   } else {
 133     return mKey.mElement->GetAnimatedAttr(mKey.mAttributeNamespaceID,
 134                                           mKey.mAttributeName);
 135   }
 136   return nullptr;
 137 }
 138
 139 uint32_t
 140 nsSMILCompositor::GetFirstFuncToAffectSandwich()
 141 {
 142   uint32_t i;
 143   for (i = mAnimationFunctions.Length(); i > 0; --i) {
 144     nsSMILAnimationFunction* curAnimFunc = mAnimationFunctions[i-1];
 145     // In the following, the lack of short-circuit behavior of |= means that we
 146     // will ALWAYS run UpdateCachedTarget (even if mForceCompositing is true)
 147     // but only call HasChanged and WasSkippedInPrevSample if necessary.  This
 148     // is important since we need UpdateCachedTarget to run in order to detect
 149     // changes to the target in subsequent samples.
 150     mForceCompositing |=
 151       curAnimFunc->UpdateCachedTarget(mKey) ||
 152       curAnimFunc->HasChanged() ||
 153       curAnimFunc->WasSkippedInPrevSample();
 154
 155     if (curAnimFunc->WillReplace()) {
 156       --i;
 157       break;
 158     }
 159   }
 160   // Mark remaining animation functions as having been skipped so if we later
 161   // use them we'll know to force compositing.
 162   // Note that we only really need to do this if something has changed
 163   // (otherwise we would have set the flag on a previous sample) and if
 164   // something has changed mForceCompositing will be true.
 165   if (mForceCompositing) {
 166     for (uint32_t j = i; j > 0; --j) {
 167       mAnimationFunctions[j-1]->SetWasSkipped();
 168     }
 169   }
 170   return i;
 171 }
 172
 173 void
 174 nsSMILCompositor::UpdateCachedBaseValue(const nsSMILValue& aBaseValue)
 175 {
 176   if (!mCachedBaseValue) {
 177     // We don't have last sample's base value cached. Assume it's changed.
 178     mCachedBaseValue = new nsSMILValue(aBaseValue);
 179     NS_WARN_IF_FALSE(mCachedBaseValue, "failed to cache base value (OOM?)");
 180     mForceCompositing = true;
 181   } else if (*mCachedBaseValue != aBaseValue) {
 182     // Base value has changed since last sample.
 183     *mCachedBaseValue = aBaseValue;
 184     mForceCompositing = true;
 185   }
 186 }