Compositor animations for Independent CSS Transform Properties

Source/core/animation/KeyframeEffect.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 111 matching lines @@
         ASSERT(animation()->source() == this);
         animation()->setCompositorPending(true);
     }
 }
 
 static AnimationStack& ensureAnimationStack(Element* element)
 {
     return element->ensureElementAnimations().defaultStack();
 }
 
+bool KeyframeEffect::hasMultipleTransformProperties() const
+{
+    if (!m_target->computedStyle())
+        return false;
+
+    unsigned transformPropertyCount = 0;
+    if (m_target->computedStyle()->hasTransformOperations())
+        transformPropertyCount++;
+    if (m_target->computedStyle()->rotate())
+        transformPropertyCount++;
+    if (m_target->computedStyle()->scale())
+        transformPropertyCount++;
+    if (m_target->computedStyle()->translate())
+        transformPropertyCount++;
+    return transformPropertyCount > 1;
+}
+
+// Returns true if transform, translate, rotate or scale is composited
+// and a motion path or other transform properties
+// has been introduced on the element
+bool KeyframeEffect::hasIncompatibleStyle()
+{
+    if (!m_target->computedStyle())
+        return false;
+
+    bool affectsTransform = animation()->affects(*m_target, CSSPropertyTransform)
+        || animation()->affects(*m_target, CSSPropertyScale)
+        || animation()->affects(*m_target, CSSPropertyRotate)
+        || animation()->affects(*m_target, CSSPropertyTranslate);
+
+    if (animation()->hasActiveAnimationsOnCompositor()) {
+        if (m_target->computedStyle()->hasMotionPath() && affectsTransform)
+            return true;
+        return hasMultipleTransformProperties();
+    }
+
+    return false;
+}
+
 void KeyframeEffect::applyEffects()
 {
     ASSERT(isInEffect());
     ASSERT(animation());
     if (!m_target || !m_model)
         return;
 
-    // Cancel composited animation of transform if a motion path, translate,
-    // rotate or scale operation has been introduced on the element.
-    if (m_target->computedStyle()
-        && (m_target->computedStyle()->hasMotionPath()
-            || m_target->computedStyle()->translate()
-            || m_target->computedStyle()->rotate()
-            || m_target->computedStyle()->scale())
-        && animation()->hasActiveAnimationsOnCompositor()
-        && animation()->affects(*m_target, CSSPropertyTransform)) {
+    if (hasIncompatibleStyle())
         animation()->cancelAnimationOnCompositor();
-    }
 
     double iteration = currentIteration();
     ASSERT(iteration >= 0);
     OwnPtrWillBeRawPtr<WillBeHeapVector<RefPtrWillBeMember<Interpolation>>> interpolations = m_sampledEffect ? m_sampledEffect->mutableInterpolations() : nullptr;
     // FIXME: Handle iteration values which overflow int.
     m_model->sample(static_cast<int>(iteration), timeFraction(), iterationDuration(), interpolations);
     if (m_sampledEffect) {
         m_sampledEffect->setInterpolations(interpolations.release());
     } else if (interpolations && !interpolations->isEmpty()) {
         OwnPtrWillBeRawPtr<SampledEffect> sampledEffect = SampledEffect::create(this, interpolations.release());
@@ skipping 77 matching lines @@
     clearEventDelegate();
     SampledEffect* sampledEffect = m_sampledEffect;
     m_sampledEffect = nullptr;
     if (sampledEffect)
         sampledEffect->clear();
 }
 #endif
 
 bool KeyframeEffect::isCandidateForAnimationOnCompositor(double animationPlaybackRate) const
 {
+    // Do not put transforms on compositor if more than one of them are defined
+    // in computed style because they need to be explicitly ordered
     if (!model()
         || !m_target
-        || (m_target->computedStyle() && (m_target->computedStyle()->hasMotionPath() || m_target->computedStyle()->translate() || m_target->computedStyle()->rotate() || m_target->computedStyle()->scale())))
+        || (m_target->computedStyle() && m_target->computedStyle()->hasMotionPath())
+        || hasMultipleTransformProperties())
         return false;
 
     return CompositorAnimations::instance()->isCandidateForAnimationOnCompositor(specifiedTiming(), *m_target, animation(), *model(), animationPlaybackRate);
 }
 
 bool KeyframeEffect::maybeStartAnimationOnCompositor(int group, double startTime, double currentTime, double animationPlaybackRate)
 {
     ASSERT(!hasActiveAnimationsOnCompositor());
     if (!isCandidateForAnimationOnCompositor(animationPlaybackRate))
         return false;
@@ skipping 76 matching lines @@
 
 DEFINE_TRACE(KeyframeEffect)
 {
     visitor->trace(m_target);
     visitor->trace(m_model);
     visitor->trace(m_sampledEffect);
     AnimationEffect::trace(visitor);
 }
 
 } // namespace blink