The Tor Browser: dom/smil/nsSMILMilestone.h@6474c204b198

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

     1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

     2 /* This Source Code Form is subject to the terms of the Mozilla Public

     3  * License, v. 2.0. If a copy of the MPL was not distributed with this

     4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     6 #ifndef NS_SMILMILESTONE_H_

     7 #define NS_SMILMILESTONE_H_

     9 /*

    10  * A significant moment in an nsSMILTimedElement's lifetime where a sample is

    11  * required.

    12  *

    13  * Animations register the next milestone in their lifetime with the time

    14  * container that they belong to. When the animation controller goes to run

    15  * a sample it first visits all the animations that have a registered milestone

    16  * in order of their milestone times. This allows interdependencies between

    17  * animations to be correctly resolved and events to fire in the proper order.

    18  *

    19  * A distinction is made between a milestone representing the end of an interval

    20  * and any other milestone. This is because if animation A ends at time t, and

    21  * animation B begins at the same time t (or has some other significant moment

    22  * such as firing a repeat event), SMIL's endpoint-exclusive timing model

    23  * implies that the interval end occurs first. In fact, interval ends can be

    24  * thought of as ending an infinitesimally small time before t. Therefore,

    25  * A should be sampled before B.

    26  *

    27  * Furthermore, this distinction between sampling the end of an interval and

    28  * a regular sample is used within the timing model (specifically in

    29  * nsSMILTimedElement) to ensure that all intervals ending at time t are sampled

    30  * before any new intervals are entered so that we have a fully up-to-date set

    31  * of instance times available before committing to a new interval. Once an

    32  * interval is entered, the begin time is fixed.

    33  */

    34 class nsSMILMilestone

    35 {

    36 public:

    37   nsSMILMilestone(nsSMILTime aTime, bool aIsEnd)

    38     : mTime(aTime), mIsEnd(aIsEnd)

    39   { }

    41   nsSMILMilestone()

    42     : mTime(0), mIsEnd(false)

    43   { }

    45   bool operator==(const nsSMILMilestone& aOther) const

    46   {

    47     return mTime == aOther.mTime && mIsEnd == aOther.mIsEnd;

    48   }

    50   bool operator!=(const nsSMILMilestone& aOther) const

    51   {

    52     return !(*this == aOther);

    53   }

    55   bool operator<(const nsSMILMilestone& aOther) const

    56   {

    57     // Earlier times sort first, and for equal times end milestones sort first

    58     return mTime < aOther.mTime ||

    59           (mTime == aOther.mTime && mIsEnd && !aOther.mIsEnd);

    60   }

    62   bool operator<=(const nsSMILMilestone& aOther) const

    63   {

    64     return *this == aOther || *this < aOther;

    65   }

    67   bool operator>=(const nsSMILMilestone& aOther) const

    68   {

    69     return !(*this < aOther);

    70   }

    72   nsSMILTime   mTime;  // The milestone time. This may be in container time or

    73                        // parent container time depending on where it is used.

    74   bool mIsEnd; // true if this milestone corresponds to an interval

    75                        // end, false otherwise.

    76 };

    78 #endif // NS_SMILMILESTONE_H_

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