New methods play & playReverse of Animation class

[chengenzhao]

Hi:

The animation class may need a play from current position method similar to the same name method of JavaFX Animation class.
And this will simplify the further development of AnimatedTextures.

#1244

[codecov-commenter]

Codecov Report

Attention: 9 lines in your changes are missing coverage. Please review.

Comparison is base (847bdd3) 59.69% compared to head (41755b4) 59.66%.

Files	Patch %	Lines
...main/kotlin/com/almasb/fxgl/animation/Animation.kt	0.00%	6 Missing ⚠️
.../kotlin/com/almasb/fxgl/texture/AnimatedTexture.kt	25.00%	3 Missing ⚠️

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Additional details and impacted files

@@             Coverage Diff              @@
##                dev    #1287      +/-   ##
============================================
- Coverage     59.69%   59.66%   -0.03%     
  Complexity     2961     2961              
============================================
  Files           308      308              
  Lines         15262    15271       +9     
  Branches       1561     1563       +2     
============================================
+ Hits           9111     9112       +1     
- Misses         5628     5636       +8     
  Partials        523      523              

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[AlmasB]

I'm just wondering when this would be called. The current position in the animation can be controlled with pause/resume. isAnimating is always true when the animation is active. So the only way this is actually run is when the animation is fully stopped, meaning it matches the implementation of start. Does that make sense?

[chengenzhao]

let's say there is an AnimationChannel of wall clock starts from 0 to 12 clock
in the app, we want the clock animation starts from current time
so it would be nice to have

setTimeTo(currentTime)
play()

and later we may have

play(currentTime)//starts from currentTime
//or to more specific
playFrom(currentTime)

to replace the pure start() method
and later we may need playTo(specificPauseTime) method
and may have fluent method like

animation.setTimeTo(currentTime)
                .playTo(specificTime) //when it comes to specific time, it will pause
                .playReverseTo(anotherTimeEarlier) //like resume to another time
                .play(); //continue playing the rest animation
//or
animation.play(from: currentTime, to: specificTime) //play from current time to specific time, when it comes to specific time, animation will pause
                .playReverseTo(anotherTimeEarlier) //like resume to another time
                .play(); //continue playing the rest animation