apply method

@override void apply(double progress)

Apply the given progress level to the effect's target.

Here progress is a variable that is typically in the range from 0 to 1, with 0 being the initial state, and 1 the final state of the effect. See EffectController for details.

This is a main method that MUST be implemented in every derived class.

Implementation

@override
void apply(double progress) {
  final deltaProgress = progress - previousProgress;
  final currentOpacity = target.opacity + _roundingError;
  final deltaOpacity = _opacityOffset * deltaProgress;
  final newOpacity = (currentOpacity + deltaOpacity).clamp(0, 1).toDouble();
  target.opacity = newOpacity;
  _roundingError = newOpacity - target.opacity;
}