getAlpha method
Values < 1 mix this animation with the skeleton's current pose (usually the pose resulting from lower tracks). Defaults to 1, which overwrites the skeleton's current pose with this animation.
Typically track 0 is used to completely pose the skeleton, then alpha is used on higher tracks. It doesn't make sense to use alpha on track 0 if the skeleton pose is from the last frame render.
Implementation
Future<double> getAlpha() async {
return _bindings.spine_track_entry_get_alpha(_entry);
}