observe property

Gradient observe

Observe the output Gradient which applies modifications to the gradientInput based on the animation and other provided properties, considering storyboard and the relevant mappings from
GradientAnimations -> dynamic, where dynamic matches with the key:

• GradientAnimation.colorArithmetic: ColorArithmetic
• GradientAnimation.stopsArithmetic: StopsArithmetic
• GradientAnimation.tweenSpec: Map<GradientProperty, Tween<dynamic>>

Implementation

// - `GradientAnimation.tweenSpec: TweenSpec`
//   - Where [TweenSpec] is a mapping from [GradientProperty]s -> [Tween]s
/// - `GradientAnimation.tweenSpec: Map<GradientProperty, Tween<dynamic>>`
Gradient get observe {
  if (storyboard.isEmpty || storyboard.containsKey(GradientAnimation.none)) {
    return _gradient;
  }
  var observation = _gradient;
  _makeAssertations();

  if (storyboard.containsKey(GradientAnimation.colorArithmetic)) {
    observation = _copyWith(observation,
        colors: _gradient.colors
            .map<Color>(
              (c) => (storyboard[GradientAnimation.colorArithmetic]
                      as ColorArithmetic)
                  .call(c, animation.value),
            )
            .toList());
  }

  if (storyboard.containsKey(GradientAnimation.stopsArithmetic)) {
    observation = _copyWith(observation,
        stops: interpretStops(_gradient)
            .map<double>(
              (s) => (storyboard[GradientAnimation.stopsArithmetic]
                      as StopsArithmetic)
                  .call(s, animation.value),
            )
            .toList());
  }

  if (!storyboard.containsKey(GradientAnimation.tweenSpec)) {
    return observation;
  }

  // final spec = storyboard[GradientAnimation.tweenSpec] as TweenSpec;
  final spec = storyboard[GradientAnimation.tweenSpec]
      as Map<GradientProperty, Tween<dynamic>>;
  return _copyWith(
    observation,
    begin: spec.containsKey(GradientProperty.begin)
        ? spec[GradientProperty.begin]!.evaluate(animation)
        : observation.begin,
    end: spec.containsKey(GradientProperty.end)
        ? spec[GradientProperty.end]!.evaluate(animation)
        : observation.end,
    center: spec.containsKey(GradientProperty.center)
        ? spec[GradientProperty.center]!.evaluate(animation)
        : observation.center,
    radius: spec.containsKey(GradientProperty.radius)
        ? spec[GradientProperty.radius]!.evaluate(animation)
        : observation.radius,
    focal: spec.containsKey(GradientProperty.focal)
        ? spec[GradientProperty.focal]!.evaluate(animation)
        : observation.focal,
    focalRadius: spec.containsKey(GradientProperty.focalRadius)
        ? spec[GradientProperty.focalRadius]!.evaluate(animation)
        : observation.focalRadius,
    startAngle: spec.containsKey(GradientProperty.startAngle)
        ? spec[GradientProperty.startAngle]!.evaluate(animation)
        : observation.startAngle,
    endAngle: spec.containsKey(GradientProperty.endAngle)
        ? spec[GradientProperty.endAngle]!.evaluate(animation)
        : observation.endAngle,
    softness: spec.containsKey(GradientProperty.softness)
        ? spec[GradientProperty.softness]!.evaluate(animation)
        : observation.softness,
    shadeFactor: spec.containsKey(GradientProperty.shadeFactor)
        ? spec[GradientProperty.shadeFactor]!.evaluate(animation)
        : observation.shadeFactor,
    distance: spec.containsKey(GradientProperty.distance)
        ? spec[GradientProperty.distance]!.evaluate(animation)
        : observation.distance,
  );
}