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

// Copyright 2014 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 Interpolation_h
#define Interpolation_h

#include "core/CoreExport.h"
#include "core/animation/InterpolableValue.h"
#include "wtf/Forward.h"
#include "wtf/RefCounted.h"
#include <memory>

namespace blink {

class PropertyHandle;

// Represents an animation's effect between an adjacent pair of
// PropertySpecificKeyframes.
class CORE_EXPORT Interpolation : public RefCounted<Interpolation> {
  WTF_MAKE_NONCOPYABLE(Interpolation);

 public:
  virtual ~Interpolation();

  virtual void interpolate(int iteration, double fraction);

  virtual bool isStyleInterpolation() const { return false; }
  virtual bool isInvalidatableInterpolation() const { return false; }
  virtual bool isLegacyStyleInterpolation() const { return false; }

  virtual PropertyHandle getProperty() const = 0;
  virtual bool dependsOnUnderlyingValue() const { return false; }

 protected:
  const std::unique_ptr<InterpolableValue> m_start;
  const std::unique_ptr<InterpolableValue> m_end;

  mutable double m_cachedFraction;
  mutable int m_cachedIteration;
  mutable std::unique_ptr<InterpolableValue> m_cachedValue;

  Interpolation(std::unique_ptr<InterpolableValue> start,
                std::unique_ptr<InterpolableValue> end);

 private:
  InterpolableValue* getCachedValueForTesting() const {
    return m_cachedValue.get();
  }

  friend class AnimationInterpolableValueTest;
  friend class AnimationInterpolationEffectTest;
  friend class AnimationDoubleStyleInterpolationTest;
  friend class AnimationVisibilityStyleInterpolationTest;
};

using ActiveInterpolations = Vector<RefPtr<Interpolation>, 1>;

}  // namespace blink

#endif  // Interpolation_h