gecko-dev/dom/animation/Keyframe.h

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this file,
 * You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef mozilla_dom_Keyframe_h
#define mozilla_dom_Keyframe_h

#include "nsCSSPropertyID.h"
#include "nsCSSValue.h"
#include "nsTArray.h"
#include "mozilla/ComputedTimingFunction.h"
#include "mozilla/Maybe.h"
#include "mozilla/RefPtr.h"

struct RawServoDeclarationBlock;
namespace mozilla {
namespace dom {
enum class CompositeOperation : uint8_t;
}

/**
 * A property-value pair specified on a keyframe.
 */
struct PropertyValuePair
{
  nsCSSPropertyID mProperty;
  // The specified value for the property. For shorthand properties or invalid
  // property values, we store the specified property value as a token stream
  // (string).
  nsCSSValue mValue;

  // The specified value when using the Servo backend.
  RefPtr<RawServoDeclarationBlock> mServoDeclarationBlock;

  bool operator==(const PropertyValuePair&) const;
};

/**
 * A single keyframe.
 *
 * This is the canonical form in which keyframe effects are stored and
 * corresponds closely to the type of objects returned via the getKeyframes()
 * API.
 *
 * Before computing an output animation value, however, we flatten these frames
 * down to a series of per-property value arrays where we also resolve any
 * overlapping shorthands/longhands, convert specified CSS values to computed
 * values, etc.
 *
 * When the target element or style context changes, however, we rebuild these
 * per-property arrays from the original list of keyframes objects. As a result,
 * these objects represent the master definition of the effect's values.
 */
struct Keyframe
{
  Keyframe() = default;
  Keyframe(const Keyframe& aOther) = default;
  Keyframe(Keyframe&& aOther)
  {
    *this = Move(aOther);
  }

  Keyframe& operator=(const Keyframe& aOther) = default;
  Keyframe& operator=(Keyframe&& aOther)
  {
    mOffset         = aOther.mOffset;
    mComputedOffset = aOther.mComputedOffset;
    mTimingFunction = Move(aOther.mTimingFunction);
    mComposite      = Move(aOther.mComposite);
    mPropertyValues = Move(aOther.mPropertyValues);
    return *this;
  }

  Maybe<double>                 mOffset;
  static constexpr double kComputedOffsetNotSet = -1.0;
  double                        mComputedOffset = kComputedOffsetNotSet;
  Maybe<ComputedTimingFunction> mTimingFunction; // Nothing() here means
                                                 // "linear"
  Maybe<dom::CompositeOperation> mComposite;
  nsTArray<PropertyValuePair>   mPropertyValues;
};

}

#endif // mozilla_dom_Keyframe_h