alpha vs autoAlpha?

[Guest aezzell]

Is there a benefit to using one over the other? If so, in which case(s) would you use each?

 

Thanks.

[Carl]

autoAlpha effects an object's visible property as well as alpha.

 

this is handy when you want to fade out a button that responds to mouse events.

 

if you do an alpha tween to alpha:0 on a button, it will be fully transparent, but still clickable.

 

if you do an autoAlpha:0, it will fade the alpha to 0 and in addition set the visible to false when the fade is done.

 

http://www.greensock.com/as/docs/tween/ ... lugin.html

[Guest aezzell]

Thanks.

 

So what's the benefit of using alpha instead of just always using autoAlpha?

[DaniLaura]

I wouldn't call using alpha instead of autoAlpha a benefit

 

Basically when the object is fully-transparent the object is still present in the display list and Flash still needs to draw the transparent pixels of your object.

 

Performance-wise, if you don't need your object to be able to respond to mouse events, such as ROLL_OVER, CLICK etc., it's much better to use autoAlpha instead, since autoAlpha sets your object's visible property to false at the end of the tween, thus preventing its transparent pixels from being drawn anymore, until you set the object to autoAlpha:1

 

Does that make sense?

[Carl]

autoAlpha is a plugin so it needs to be manually activated in TweenLite and it does add a miniscule amount of size to your swf. Some people may consider that a benefit of using regular alpha.

[Guest aezzell]

Thanks, guys.

 

Is this correct?

 

autoAlpha is activated by default in TweenMax. So if you're already using TweenMax, there's no benefit to using alpha. (Unless for some reason you want things you can't see to respond to MouseEvents).

 

But if you're only using TweenLite, there's some small size benefit to just using alpha, and setting visible to false if having it true might cause a problem.

 

Yes?

[DaniLaura]

Your understanding is correct