summaryrefslogtreecommitdiffstats
path: root/dom/animation/CSSTransition.h
blob: b2a76d34164ccd0516025fb700b9ee88ac652d07 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
/* -*- 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_CSSTransition_h
#define mozilla_dom_CSSTransition_h

#include "mozilla/ComputedTiming.h"
#include "mozilla/dom/Animation.h"
#include "mozilla/AnimatedPropertyID.h"
#include "mozilla/StyleAnimationValue.h"
#include "AnimationCommon.h"

class nsIGlobalObject;

namespace mozilla {
namespace dom {

class CSSTransition final : public Animation {
 public:
  explicit CSSTransition(nsIGlobalObject* aGlobal,
                         const AnimatedPropertyID& aProperty)
      : Animation(aGlobal),
        mPreviousTransitionPhase(TransitionPhase::Idle),
        mNeedsNewAnimationIndexWhenRun(false),
        mTransitionProperty(aProperty) {}

  JSObject* WrapObject(JSContext* aCx,
                       JS::Handle<JSObject*> aGivenProto) override;

  CSSTransition* AsCSSTransition() override { return this; }
  const CSSTransition* AsCSSTransition() const override { return this; }

  // CSSTransition interface
  void GetTransitionProperty(nsString& aRetVal) const;

  // Animation interface overrides
  AnimationPlayState PlayStateFromJS() const override;
  bool PendingFromJS() const override;
  void PlayFromJS(ErrorResult& aRv) override;

  // A variant of Play() that avoids posting style updates since this method
  // is expected to be called whilst already updating style.
  void PlayFromStyle() {
    ErrorResult rv;
    PlayNoUpdate(rv, Animation::LimitBehavior::Continue);
    // play() should not throw when LimitBehavior is Continue
    MOZ_ASSERT(!rv.Failed(), "Unexpected exception playing transition");
  }

  void CancelFromStyle(PostRestyleMode aPostRestyle) {
    // The animation index to use for compositing will be established when
    // this transition next transitions out of the idle state but we still
    // update it now so that the sort order of this transition remains
    // defined until that moment.
    //
    // See longer explanation in CSSAnimation::CancelFromStyle.
    mAnimationIndex = sNextAnimationIndex++;
    mNeedsNewAnimationIndexWhenRun = true;

    Animation::Cancel(aPostRestyle);

    // It is important we do this *after* calling Cancel().
    // This is because Cancel() will end up posting a restyle and
    // that restyle should target the *transitions* level of the cascade.
    // However, once we clear the owning element, CascadeLevel() will begin
    // returning CascadeLevel::Animations.
    mOwningElement = OwningElementRef();
  }

  void SetEffectFromStyle(KeyframeEffect*);

  void Tick(TickState&) override;

  const AnimatedPropertyID& TransitionProperty() const;
  AnimationValue ToValue() const;

  bool HasLowerCompositeOrderThan(const CSSTransition& aOther) const;
  EffectCompositor::CascadeLevel CascadeLevel() const override {
    return IsTiedToMarkup() ? EffectCompositor::CascadeLevel::Transitions
                            : EffectCompositor::CascadeLevel::Animations;
  }

  void SetCreationSequence(uint64_t aIndex) {
    MOZ_ASSERT(IsTiedToMarkup());
    mAnimationIndex = aIndex;
  }

  // Sets the owning element which is used for determining the composite
  // oder of CSSTransition objects generated from CSS markup.
  //
  // @see mOwningElement
  void SetOwningElement(const OwningElementRef& aElement) {
    mOwningElement = aElement;
  }
  // True for transitions that are generated from CSS markup and continue to
  // reflect changes to that markup.
  bool IsTiedToMarkup() const { return mOwningElement.IsSet(); }

  // Return the animation current time based on a given TimeStamp, a given
  // start time and a given playbackRate on a given timeline.  This is useful
  // when we estimate the current animated value running on the compositor
  // because the animation on the compositor may be running ahead while
  // main-thread is busy.
  static Nullable<TimeDuration> GetCurrentTimeAt(
      const AnimationTimeline& aTimeline, const TimeStamp& aBaseTime,
      const TimeDuration& aStartTime, double aPlaybackRate);

  void MaybeQueueCancelEvent(const StickyTimeDuration& aActiveTime) override {
    QueueEvents(aActiveTime);
  }

  // Compute the portion of the *value* space that we should be through
  // at the current time.  (The input to the transition timing function
  // has time units, the output has value units.)
  double CurrentValuePortion() const;

  const AnimationValue& StartForReversingTest() const {
    return mStartForReversingTest;
  }
  double ReversePortion() const { return mReversePortion; }

  void SetReverseParameters(AnimationValue&& aStartForReversingTest,
                            double aReversePortion) {
    mStartForReversingTest = std::move(aStartForReversingTest);
    mReversePortion = aReversePortion;
  }

  struct ReplacedTransitionProperties {
    TimeDuration mStartTime;
    double mPlaybackRate;
    TimingParams mTiming;
    Maybe<StyleComputedTimingFunction> mTimingFunction;
    AnimationValue mFromValue, mToValue;
  };
  void SetReplacedTransition(
      ReplacedTransitionProperties&& aReplacedTransition) {
    mReplacedTransition.emplace(std::move(aReplacedTransition));
  }

  // For a new transition interrupting an existing transition on the
  // compositor, update the start value to match the value of the replaced
  // transitions at the current time.
  void UpdateStartValueFromReplacedTransition();

 protected:
  virtual ~CSSTransition() {
    MOZ_ASSERT(!mOwningElement.IsSet(),
               "Owning element should be cleared "
               "before a CSS transition is destroyed");
  }

  // Animation overrides
  void UpdateTiming(SeekFlag aSeekFlag,
                    SyncNotifyFlag aSyncNotifyFlag) override;

  void QueueEvents(const StickyTimeDuration& activeTime = StickyTimeDuration());

  enum class TransitionPhase;

  // The (pseudo-)element whose computed transition-property refers to this
  // transition (if any).
  //
  // This is used for determining the relative composite order of transitions
  // generated from CSS markup.
  //
  // Typically this will be the same as the target element of the keyframe
  // effect associated with this transition. However, it can differ in the
  // following circumstances:
  //
  // a) If script removes or replaces the effect of this transition,
  // b) If this transition is cancelled (e.g. by updating the
  //    transition-property or removing the owning element from the document),
  // c) If this object is generated from script using the CSSTransition
  //    constructor.
  //
  // For (b) and (c) the owning element will return !IsSet().
  OwningElementRef mOwningElement;

  // The 'transition phase' used to determine which transition events need
  // to be queued on this tick.
  // See: https://drafts.csswg.org/css-transitions-2/#transition-phase
  enum class TransitionPhase {
    Idle = static_cast<int>(ComputedTiming::AnimationPhase::Idle),
    Before = static_cast<int>(ComputedTiming::AnimationPhase::Before),
    Active = static_cast<int>(ComputedTiming::AnimationPhase::Active),
    After = static_cast<int>(ComputedTiming::AnimationPhase::After),
    Pending
  };
  TransitionPhase mPreviousTransitionPhase;

  // When true, indicates that when this transition next leaves the idle state,
  // its animation index should be updated.
  bool mNeedsNewAnimationIndexWhenRun;

  // Store the transition property and to-value here since we need that
  // information in order to determine if there is an existing transition
  // for a given style change. We can't store that information on the
  // effect however since it can be replaced using the Web Animations API.
  AnimatedPropertyID mTransitionProperty;
  AnimationValue mTransitionToValue;

  // This is the start value to be used for a check for whether a
  // transition is being reversed.  Normally the same as
  // mEffect->mProperties[0].mSegments[0].mFromValue, except when this
  // transition started as the reversal of another in-progress transition
  // or when the effect has been mutated using the Web Animations API.
  //
  // Needed so we can handle two reverses in a row.
  AnimationValue mStartForReversingTest;

  // Likewise, the portion (in value space) of the "full" reversed
  // transition that we're actually covering.  For example, if a :hover
  // effect has a transition that moves the element 10px to the right
  // (by changing 'left' from 0px to 10px), and the mouse moves in to
  // the element (starting the transition) but then moves out after the
  // transition has advanced 4px, the second transition (from 10px/4px
  // to 0px) will have mReversePortion of 0.4.  (If the mouse then moves
  // in again when the transition is back to 2px, the mReversePortion
  // for the third transition (from 0px/2px to 10px) will be 0.8.
  double mReversePortion = 1.0;

  Maybe<ReplacedTransitionProperties> mReplacedTransition;
};

}  // namespace dom

}  // namespace mozilla

#endif  // mozilla_dom_CSSTransition_h