[actionstep-core] Animation implementation changes

[Ray C. <rc...@gm...>]

Hi,
I've made some changes to NSAnimation and related classes.

There are now 2 main classes to use: ASAnimation and NSAnimation. No,
that's not a typo, there are 2 such classes. What ASAnimation does is
allow the delegate with the method animationDidAdvance, which is not
part of the Cocoa specs.

This is an alternative to what Apple recommends: subclassing
NSAnimation and overriding the setCurrentProgress method. I find this
too cumbersome, so the framework now contains ASAnimation which saves
you the trouble of subclassing NSAnimation.

I've also added more constants to NSAnimationCurve and removed methods
like setBegin/setChange such that full Cocoa-spec compliance is
ensured in NSAnimation.

See /trunk/test/org.actionstep.test.ASTestAnimation for an example.

To animate in the RP(Robert Penner)-style, you would do this previously:
>>>
anim.setBegin(sx);
anim.setChange(dx);
anim.setFrameRate(30);
anim.setDelegate({
  animationDidAdvance:function(foo:NSAnimation):Void {
    mc._x = foo.currentValue();
  }
});
<<<
Now you to do the same thing, you will do:
>>>
// no more setBegin/Change
anim.setFrameRate(1/30);  //note change in frame rate
anim.setDelegate({
  animationDidAdvance:function(foo:NSAnimation):Void {
    mc._x = sx + foo.currentValue() * dx;
  }
});
<<<

-currentValue is always between 0 and 1, so you can think of it as a
fraction of the value to animate. Do not confuse this with
-currentProgress which tells you how much of the animation has
completed.

-- 
Cheers,
Ray Chuan