lerpGradient function

Implementation

Color lerpGradient(List<Color> colors, List<double> stops, double t) {
  if (colors.isEmpty) {
    throw ArgumentError('"colors" is empty.');
  } else if (colors.length == 1) {
    return colors[0];
  }

  if (stops.length != colors.length) {
    stops = [];

    /// provided gradientColorStops is invalid and we calculate it here
    colors.asMap().forEach((index, color) {
      final percent = 1.0 / (colors.length - 1);
      stops.add(percent * index);
    });
  }

  for (var s = 0; s < stops.length - 1; s++) {
    final leftStop = stops[s];
    final rightStop = stops[s + 1];
    final leftColor = colors[s];
    final rightColor = colors[s + 1];
    if (t <= leftStop) {
      return leftColor;
    } else if (t < rightStop) {
      final sectionT = (t - leftStop) / (rightStop - leftStop);
      return Color.lerp(leftColor, rightColor, sectionT)!;
    }
  }
  return colors.last;
}