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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 NS_SMILMILESTONE_H_
#define NS_SMILMILESTONE_H_
/*
* A significant moment in an nsSMILTimedElement's lifetime where a sample is
* required.
*
* Animations register the next milestone in their lifetime with the time
* container that they belong to. When the animation controller goes to run
* a sample it first visits all the animations that have a registered milestone
* in order of their milestone times. This allows interdependencies between
* animations to be correctly resolved and events to fire in the proper order.
*
* A distinction is made between a milestone representing the end of an interval
* and any other milestone. This is because if animation A ends at time t, and
* animation B begins at the same time t (or has some other significant moment
* such as firing a repeat event), SMIL's endpoint-exclusive timing model
* implies that the interval end occurs first. In fact, interval ends can be
* thought of as ending an infinitesimally small time before t. Therefore,
* A should be sampled before B.
*
* Furthermore, this distinction between sampling the end of an interval and
* a regular sample is used within the timing model (specifically in
* nsSMILTimedElement) to ensure that all intervals ending at time t are sampled
* before any new intervals are entered so that we have a fully up-to-date set
* of instance times available before committing to a new interval. Once an
* interval is entered, the begin time is fixed.
*/
class nsSMILMilestone
{
public:
nsSMILMilestone(nsSMILTime aTime, bool aIsEnd)
: mTime(aTime), mIsEnd(aIsEnd)
{ }
nsSMILMilestone()
: mTime(0), mIsEnd(false)
{ }
bool operator==(const nsSMILMilestone& aOther) const
{
return mTime == aOther.mTime && mIsEnd == aOther.mIsEnd;
}
bool operator!=(const nsSMILMilestone& aOther) const
{
return !(*this == aOther);
}
bool operator<(const nsSMILMilestone& aOther) const
{
// Earlier times sort first, and for equal times end milestones sort first
return mTime < aOther.mTime ||
(mTime == aOther.mTime && mIsEnd && !aOther.mIsEnd);
}
bool operator<=(const nsSMILMilestone& aOther) const
{
return *this == aOther || *this < aOther;
}
bool operator>=(const nsSMILMilestone& aOther) const
{
return !(*this < aOther);
}
nsSMILTime mTime; // The milestone time. This may be in container time or
// parent container time depending on where it is used.
bool mIsEnd; // true if this milestone corresponds to an interval
// end, false otherwise.
};
#endif // NS_SMILMILESTONE_H_
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