| Package | com.greensock.plugins |
| Class | public class TweenPlugin |
| Inheritance | TweenPlugin  Object |
| Subclasses | BezierPlugin, ColorPropsPlugin, CSSPlugin, CSSRulePlugin, EaselPlugin, RaphaelPlugin, RoundPropsPlugin, ScrollToPlugin |
USAGE:
To create your own plugin, extend TweenPlugin and override whichever methods you need (typically
_onInitTween() and setRatio()). To make things easier, we have included a
file named TEMPLATE_Plugin.js in the plugins directory that serves as a jumping-off point
and it has some comments in the code. _onInitTween() is called when the tween renders for
the first time and setRatio() is called on every update and passes a ratio parameter which
is typically a value between 0 and 1, and it changes according to the ease). There are a few
key concepts to keep in mind:
"scrollTo" and it also overwrites other concurrent
tweens that are handling the "scrollTo" but you may have a ScalePlugin that handles both "scaleX" and
"scaleY" properties, thus the comma-delimited list would look like "scale,scaleX,scaleY".
The first name in the list must be unique - two plugins cannot handle the same primary property. _onInitTween() method
is called. That's where you'll want to record any initial values and prepare for the tween.
_onInitTween() should return a Boolean value that essentially indicates whether
or not the plugin initted successfully. If you return false, TweenLite/Max will just use a
normal tween for the value, ignoring the plugin for that particular tween. For example,
maybe your tween only works with DOM elements, so if the target isn't one you could
return false
setRatio() method will be called on every frame during the course of the tween
and it will be passed a single parameter that's a multiplier (typically between 0 and 1, according
to the ease) describing the total amount of change from the beginning of the tween (0). It is normally
zero at the beginning of the tween and 1 at the end, and inbetween it could be any value based on the
ease applied (for example, an ElasticOut ease would cause the value to shoot past 1 and
back again before the end of the tween). So if the tween uses the Linear.ease, when it's
halfway finished, setRatio(0.5) would be called_overwriteProps is an array that should contain the properties that your
plugin should overwrite in "auto" overwrite mode. For example, an autoAlpha
plugin could control the "visible" and "alpha" properties of an object,
so if another tween is created that controls the alpha of the target object,
your plugin's _kill() method will be called which should handle killing the
"alpha" part of the tween. It is your responsibility to populate (and depopulate)
the _overwriteProps Array. Failure to do so properly can cause odd overwriting
behavior._roundProps() method that gets called by the RoundPropsPlugin if the
user requests that certain properties get rounded to the nearest integer. If you use
_addTween() method to add property tweens, rounding will happen automatically
(if necessary), but if you don't use _addTween() and prefer to manually calculate
tween values in your setRatio() method, just remember to override the _roundProps()
method if that makes sense in your plugin (some plugins wouldn't need to accommodate rounding, like color
plugins, in which case you can ignore the method altogether)._onDisable() method
(named exactly that) to your plugin. It will automatically be called when the tween gets disabled (typically
when it finishes and is removed from its parent timeline). Same for _onEnable() if you
need to run code when a tween is enabled. These methods should return a Boolean value indicating
whether or not they changed any properties on the target becaues if so (true), it helps
notify any initting tweens of the same target to re-init. It is very rare that an _onDisable()
or _onEnable() method is necessary, but it can be useful for things like MotionBlurPlugin
which must do some very advanced things, hiding the target, changing its alpha to almost 0, etc. only
while the tween occurs. If another alpha tween of that same target overwrites an existing motionBlur
of the same target, the alpha would be at the wrong value normally, but the if the _onDisable()
returns true, it would force the new tween to re-init AFTER the alpha was fixed inside
the _onDisable(). Again, this is VERY rare._addTween() to create property tweens internally, make sure you override
the _kill() method which will be passed a vars parameter with properties that need
to be killed (typically for overwriting).Copyright 2008-2012, GreenSock. All rights reserved. This work is subject to the terms in http://www.greensock.com/terms_of_use.html or for Club GreenSock members, the software agreement that was issued with the membership.