gecko-dev/content/smil/nsSMILMilestone.h

111 lines
4.4 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is the Mozilla SMIL module.
*
* The Initial Developer of the Original Code is Brian Birtles.
* Portions created by the Initial Developer are Copyright (C) 2009
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Brian Birtles <birtles@gmail.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#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, PRBool aIsEnd)
: mTime(aTime), mIsEnd(aIsEnd)
{ }
nsSMILMilestone()
: mTime(0), mIsEnd(PR_FALSE)
{ }
PRBool operator==(const nsSMILMilestone& aOther) const
{
return mTime == aOther.mTime && mIsEnd == aOther.mIsEnd;
}
PRBool operator!=(const nsSMILMilestone& aOther) const
{
return !(*this == aOther);
}
PRBool 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);
}
PRBool operator<=(const nsSMILMilestone& aOther) const
{
return *this == aOther || *this < aOther;
}
PRBool 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.
PRPackedBool mIsEnd; // PR_TRUE if this milestone corresponds to an interval
// end, PR_FALSE otherwise.
};
#endif // NS_SMILMILESTONE_H_