WIP: Implement CSS transitions on top of InterpolationTypes instead of AnimatableValues

third_party/WebKit/Source/core/animation/TransitionEffectModel.h

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef TransitionEffectModel_h
+#define TransitionEffectModel_h
+
+#include "core/animation/EffectModel.h"
+#include "core/animation/PairwiseInterpolation.h"
+#include "platform/animation/TimingFunction.h"
+
+namespace blink {
+
+class Element;
+class TransitionEffectModelTest;
+
+class TransitionEffectModel : public EffectModel {
+public:
+    static TransitionEffectModel* create(PassRefPtr<PairwiseInterpolation> pairwiseInterpolation, double delayOffset, PassRefPtr<TimingFunction> timingFunction)
+    {
+        return new TransitionEffectModel(pairwiseInterpolation, delayOffset, timingFunction);
+    }
+
+private:
+    TransitionEffectModel(PassRefPtr<PairwiseInterpolation> pairwiseInterpolation, double delayOffset, PassRefPtr<TimingFunction> timingFunction)
+        : m_interpolation(pairwiseInterpolation)
+        , m_delayOffset(delayOffset)
+        , m_timingFunction(timingFunction)
+    {
+        DCHECK(delayOffset >= 0 && delayOffset < 1);
+    }
+
+    bool affects(PropertyHandle property) const final
+    {
+        return m_interpolation->getProperty() == property;
+    }
+
+    bool isTransitionEffectModel() const final { return true; }
+
+    void sampleImpl(int iteration, double fraction, double iterationDuration, Vector<RefPtr<Interpolation>>& result) const final
+    {
+        double delayedFraction = 0;
+        if (fraction > m_delayOffset) {
+            delayedFraction = (fraction - m_delayOffset) / (1 - m_delayOffset);
+        }
+        delayedFraction = m_timingFunction->evaluate(delayedFraction, iterationDuration);
+        m_interpolation->interpolate(0, delayedFraction);
+        if (result.isEmpty()) {
+            result.append(m_interpolation);
+        } else {
+            result[0] = m_interpolation;
+            result.shrink(1);
+        }
+    }
+
+    const RefPtr<PairwiseInterpolation> m_interpolation;
+    const double m_delayOffset;
+    RefPtr<TimingFunction> m_timingFunction;
+};
+
+} // namespace blink
+
+#endif // TransitionEffectModel_h