updateThemeFromBackground function

void updateThemeFromBackground(String? hex)

Updates theme based on background hex color (e.g., '#1a1a1a').

Automatically determines if the background is dark based on luminance.

Implementation

void updateThemeFromBackground(String? hex) {
  if (hex == null || hex.isEmpty) return;
  final h = hex.startsWith('#') ? hex.substring(1) : hex;
  if (h.length != 6) return;

  final r = int.tryParse(h.substring(0, 2), radix: 16);
  final g = int.tryParse(h.substring(2, 4), radix: 16);
  final b = int.tryParse(h.substring(4, 6), radix: 16);
  if (r == null || g == null || b == null) return;

  // Perceived luminance; threshold tuned for terminals
  final lum = (0.2126 * r + 0.7152 * g + 0.0722 * b) / 255.0;
  _hasDarkBackground = lum < 0.5;
}