build method

  1. @override
void build()
override

Declares this node's children and behavior.

Runs once on mount, and again on every rebuild.

super.build() is required, as skipping it drops whatever the superclass declared.

Implementation

@override
void build() {
  super.build();
  final base = _base ?? paint.color.a;

  onProgress((progress) {
    paint.color = paint.color.withValues(alpha: base + _span * progress);
  });
}