fadeOut
Fades content out from fully opaque to targetAlpha.
Parameters
spec
The animation spec for the fade. Defaults to spring.
targetAlpha
The ending alpha value (0 = transparent, 1 = opaque).
Fades content out over duration — a shortcut for fadeOut(tween(duration), targetAlpha).
Parameters
duration
How long the fade runs.
targetAlpha
The ending alpha value (0 = transparent, 1 = opaque).