chromium/src/third_party/blink/renderer/platform/animation/timing_function.h

/*
 * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
 *           (C) 2000 Antti Koivisto (koivisto@kde.org)
 *           (C) 2000 Dirk Mueller (mueller@kde.org)
 * Copyright (C) 2003, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
 * Copyright (C) 2006 Graham Dennis (graham.dennis@gmail.com)
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_ANIMATION_TIMING_FUNCTION_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_ANIMATION_TIMING_FUNCTION_H_

#include "base/memory/scoped_refptr.h"
#include "base/notreached.h"
#include "third_party/blink/renderer/platform/platform_export.h"
#include "third_party/blink/renderer/platform/runtime_enabled_features.h"
#include "third_party/blink/renderer/platform/wtf/assertions.h"
#include "third_party/blink/renderer/platform/wtf/casting.h"
#include "third_party/blink/renderer/platform/wtf/std_lib_extras.h"
#include "third_party/blink/renderer/platform/wtf/text/wtf_string.h"
#include "third_party/blink/renderer/platform/wtf/thread_safe_ref_counted.h"
#include "ui/gfx/animation/keyframe/timing_function.h"

namespace blink {

class PLATFORM_EXPORT TimingFunction
    : public ThreadSafeRefCounted<TimingFunction> {
 public:
  using Type = gfx::TimingFunction::Type;
  using LimitDirection = gfx::TimingFunction::LimitDirection;

  virtual ~TimingFunction() = default;

  Type GetType() const { return type_; }

  virtual String ToString() const = 0;

  // Evaluates the timing function at the given fraction. The limit direction
  // applies when evaluating a function at a discontinuous boundary and
  // indicates if the left or right limit should be applied.
  virtual double Evaluate(double fraction,
                          LimitDirection limit_direction) const {
    return Evaluate(fraction);
  }

  // Evaluates the timing function at the given fraction.
  virtual double Evaluate(double fraction) const = 0;

  // This function returns the minimum and maximum values obtainable when
  // calling evaluate();
  virtual void Range(double* min_value, double* max_value) const = 0;

  // Create CC instance.
  virtual std::unique_ptr<gfx::TimingFunction> CloneToCC() const = 0;

 protected:
  TimingFunction(Type type) : type_(type) {}

 private:
  Type type_;
};

class PLATFORM_EXPORT LinearTimingFunction final : public TimingFunction {
 public:
  static LinearTimingFunction* Shared() {
    DEFINE_STATIC_REF(LinearTimingFunction, linear,
                      (base::AdoptRef(new LinearTimingFunction())));
    return linear;
  }

  ~LinearTimingFunction() override = default;

  // TimingFunction implementation.
  String ToString() const override;
  double Evaluate(double fraction) const override;
  void Range(double* min_value, double* max_value) const override;
  std::unique_ptr<gfx::TimingFunction> CloneToCC() const override;

 private:
  LinearTimingFunction() : TimingFunction(Type::LINEAR) {}
};

class PLATFORM_EXPORT CubicBezierTimingFunction final : public TimingFunction {
 public:
  using EaseType = gfx::CubicBezierTimingFunction::EaseType;

  static scoped_refptr<CubicBezierTimingFunction> Create(double x1,
                                                         double y1,
                                                         double x2,
                                                         double y2) {
    return base::AdoptRef(new CubicBezierTimingFunction(x1, y1, x2, y2));
  }

  static CubicBezierTimingFunction* Preset(EaseType);

  ~CubicBezierTimingFunction() override = default;

  // TimingFunction implementation.
  String ToString() const override;
  double Evaluate(double fraction) const override;
  void Range(double* min_value, double* max_value) const override;
  std::unique_ptr<gfx::TimingFunction> CloneToCC() const override;

  double X1() const {
    DCHECK_EQ(GetEaseType(), EaseType::CUSTOM);
    return x1_;
  }
  double Y1() const {
    DCHECK_EQ(GetEaseType(), EaseType::CUSTOM);
    return y1_;
  }
  double X2() const {
    DCHECK_EQ(GetEaseType(), EaseType::CUSTOM);
    return x2_;
  }
  double Y2() const {
    DCHECK_EQ(GetEaseType(), EaseType::CUSTOM);
    return y2_;
  }
  EaseType GetEaseType() const { return bezier_->ease_type(); }

 private:
  explicit CubicBezierTimingFunction(EaseType ease_type)
      : TimingFunction(Type::CUBIC_BEZIER),
        bezier_(gfx::CubicBezierTimingFunction::CreatePreset(ease_type)),
        x1_(),
        y1_(),
        x2_(),
        y2_() {}

  CubicBezierTimingFunction(double x1, double y1, double x2, double y2)
      : TimingFunction(Type::CUBIC_BEZIER),
        bezier_(gfx::CubicBezierTimingFunction::Create(x1, y1, x2, y2)),
        x1_(x1),
        y1_(y1),
        x2_(x2),
        y2_(y2) {}

  std::unique_ptr<gfx::CubicBezierTimingFunction> bezier_;

  // TODO(loyso): Get these values from m_bezier->bezier_ (gfx::CubicBezier)
  const double x1_;
  const double y1_;
  const double x2_;
  const double y2_;
};

class PLATFORM_EXPORT StepsTimingFunction final : public TimingFunction {
 public:
  using StepPosition = gfx::StepsTimingFunction::StepPosition;

  static scoped_refptr<StepsTimingFunction> Create(int steps,
                                                   StepPosition step_position) {
    return base::AdoptRef(new StepsTimingFunction(steps, step_position));
  }

  static StepsTimingFunction* Preset(StepPosition position) {
    DEFINE_STATIC_REF(StepsTimingFunction, start,
                      Create(1, StepPosition::START));
    DEFINE_STATIC_REF(StepsTimingFunction, end, Create(1, StepPosition::END));
    switch (position) {
      case StepPosition::START:
        return start;
      case StepPosition::END:
        return end;
      default:
        NOTREACHED();
        return end;
    }
  }

  ~StepsTimingFunction() override = default;

  // TimingFunction implementation.
  String ToString() const override;
  double Evaluate(double fraction,
                  LimitDirection limit_direction) const override;
  double Evaluate(double fraction) const override;

  void Range(double* min_value, double* max_value) const override;
  std::unique_ptr<gfx::TimingFunction> CloneToCC() const override;

  int NumberOfSteps() const { return steps_->steps(); }
  StepPosition GetStepPosition() const { return steps_->step_position(); }

 private:
  StepsTimingFunction(int steps, StepPosition step_position)
      : TimingFunction(Type::STEPS),
        steps_(gfx::StepsTimingFunction::Create(steps, step_position)) {}

  std::unique_ptr<gfx::StepsTimingFunction> steps_;
};

PLATFORM_EXPORT scoped_refptr<TimingFunction>
CreateCompositorTimingFunctionFromCC(const gfx::TimingFunction*);

PLATFORM_EXPORT bool operator==(const LinearTimingFunction&,
                                const TimingFunction&);
PLATFORM_EXPORT bool operator==(const CubicBezierTimingFunction&,
                                const TimingFunction&);
PLATFORM_EXPORT bool operator==(const StepsTimingFunction&,
                                const TimingFunction&);

PLATFORM_EXPORT bool operator==(const TimingFunction&, const TimingFunction&);
PLATFORM_EXPORT bool operator!=(const TimingFunction&, const TimingFunction&);

template <>
struct DowncastTraits<LinearTimingFunction> {
  static bool AllowFrom(const TimingFunction& value) {
    return value.GetType() == TimingFunction::Type::LINEAR;
  }
};
template <>
struct DowncastTraits<CubicBezierTimingFunction> {
  static bool AllowFrom(const TimingFunction& value) {
    return value.GetType() == TimingFunction::Type::CUBIC_BEZIER;
  }
};
template <>
struct DowncastTraits<StepsTimingFunction> {
  static bool AllowFrom(const TimingFunction& value) {
    return value.GetType() == TimingFunction::Type::STEPS;
  }
};

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_PLATFORM_ANIMATION_TIMING_FUNCTION_H_