parseCssCurve function

Curve? parseCssCurve(String value)

Parses a CSS easing function to a Flutter Curve.

Handles cubic-bezier(a, b, c, d), linear, and the four ease* keywords. Returns null for steps() and anything unrecognised — no Astryx token uses them.

Implementation

Curve? parseCssCurve(String value) {
  final trimmed = value.trim().toLowerCase();
  if (trimmed == 'linear') return Curves.linear;

  final keyword = _easingKeywords[trimmed];
  if (keyword != null) return keyword;

  if (!trimmed.startsWith('cubic-bezier(') || !trimmed.endsWith(')')) {
    return null;
  }
  final body = trimmed.substring('cubic-bezier('.length, trimmed.length - 1);
  final parts = splitTopLevelCommas(body);
  if (parts.length != 4) return null;

  final values = parts.map((p) => double.tryParse(p.trim())).toList();
  if (values.any((v) => v == null)) return null;

  return Cubic(values[0]!, values[1]!, values[2]!, values[3]!);
}