resolveAspectRatio static method

Implementation

static double? resolveAspectRatio(String input) {
  final String value = input.trim();
  if (value.isEmpty) return null;
  if (value.toLowerCase() == 'auto') return null;

  // Try fraction form: a / b (allow spaces around slash)
  final int slash = value.indexOf('/');
  if (slash != -1) {
    final String a = value.substring(0, slash).trim();
    final String b = value.substring(slash + 1).trim();
    final double? num = double.tryParse(a);
    final double? den = double.tryParse(b);
    if (num == null || den == null) return null;
    if (den == 0) return null;
    return num / den;
  }

  // Single number form
  final double? single = double.tryParse(value);
  if (single == null) return null;
  return single.isFinite && single > 0 ? single : null;
}