M3ECustomExpressive

snippet.dart

/// Expressive emphasis tweaks layered on top of baseline M3 type.
/// Keep line-height the same; only tune weight/letter-spacing for emphasis.
/// For most purposes, the M3ECustomEmphasized() construct is used.
@immutable
class M3ECustomEmphasized {
  final TextStyle expressiveDisplayLarge;
  final TextStyle expressiveDisplayMedium;
  final TextStyle expressiveDisplaySmall;
  final TextStyle expressiveHeadlineLarge;
  final TextStyle expressiveHeadlineMedium;
  final TextStyle expressiveHeadlineSmall;
  final TextStyle expressiveTitleLarge;
  final TextStyle expressiveTitleMedium;
  final TextStyle expressiveTitleSmall;
  final TextStyle expressiveBodyLarge;
  final TextStyle expressiveBodyMedium;
  final TextStyle expressiveBodySmall;
  final TextStyle expressiveLabelLarge;
  final TextStyle expressiveLabelMedium;
  final TextStyle expressiveLabelSmall;

  const M3ECustomEmphasized({
    required this.expressiveDisplayLarge,
    required this.expressiveDisplayMedium,
    required this.expressiveDisplaySmall,
    required this.expressiveHeadlineLarge,
    required this.expressiveHeadlineMedium,
    required this.expressiveHeadlineSmall,
    required this.expressiveTitleLarge,
    required this.expressiveTitleMedium,
    required this.expressiveTitleSmall,
    required this.expressiveBodyLarge,
    required this.expressiveBodyMedium,
    required this.expressiveBodySmall,
    required this.expressiveLabelLarge,
    required this.expressiveLabelMedium,
    required this.expressiveLabelSmall,
  });

  /// M3E guidance: slightly heavier weights and tighter tracking for large roles.
  /// Since I use varaible fonts it has to have those parameters.
  M3ECustomEmphasized forBrightness(Brightness b) {
    // You could vary by brightness if desired; values below are neutral.
    return M3ECustomEmphasized(
      expressiveDisplayLarge: TextStyle(
        fontWeight: kFontWeights().expressiveDisplayLarge,
        letterSpacing: kFontTracking().expressiveDisplayLarge, // subtle tightening on big sizes
      ),
      expressiveDisplayMedium: TextStyle(
        fontWeight: kFontWeights().expressiveDisplayMedium,
        letterSpacing: kFontTracking().expressiveDisplayMedium, // subtle tightening on big sizes
      ),
      expressiveDisplaySmall: TextStyle(
        fontWeight: kFontWeights().expressiveDisplaySmall,
        letterSpacing: kFontTracking().expressiveDisplaySmall, // subtle tightening on big sizes
      ),
      expressiveHeadlineLarge: TextStyle(fontWeight: kFontWeights().expressiveHeadlineLarge, letterSpacing: kFontTracking().expressiveHeadlineLarge),
      expressiveHeadlineMedium: TextStyle(fontWeight: kFontWeights().expressiveHeadlineMedium, letterSpacing: kFontTracking().expressiveHeadlineMedium),
      expressiveHeadlineSmall: TextStyle(fontWeight: kFontWeights().expressiveHeadlineSmall, letterSpacing: kFontTracking().expressiveHeadlineSmall),
      expressiveTitleLarge: TextStyle(fontWeight: kFontWeights().expressiveTitleLarge, letterSpacing: kFontTracking().expressiveTitleLarge),
      expressiveTitleMedium: TextStyle(fontWeight: kFontWeights().expressiveTitleMedium, letterSpacing: kFontTracking().expressiveTitleMedium),
      expressiveTitleSmall: TextStyle(fontWeight: kFontWeights().expressiveTitleSmall, letterSpacing: kFontTracking().expressiveTitleSmall),
      expressiveBodyLarge: TextStyle(fontWeight: kFontWeights().expressiveBodyLarge, letterSpacing: kFontTracking().expressiveBodyLarge),
      expressiveBodyMedium: TextStyle(fontWeight: kFontWeights().expressiveBodyMedium, letterSpacing: kFontTracking().expressiveBodyMedium),
      expressiveBodySmall: TextStyle(fontWeight: kFontWeights().expressiveBodySmall, letterSpacing: kFontTracking().expressiveBodySmall),
      expressiveLabelLarge: TextStyle(fontWeight: kFontWeights().expressiveLabelLarge, letterSpacing: kFontTracking().expressiveLabelLarge),
      expressiveLabelMedium: TextStyle(fontWeight: kFontWeights().expressiveLabelMedium, letterSpacing: kFontTracking().expressiveLabelMedium),
      expressiveLabelSmall: TextStyle(fontWeight: kFontWeights().expressiveLabelSmall, letterSpacing: kFontTracking().expressiveLabelSmall),
    );
  }

  static M3ECustomEmphasized lerp(M3ECustomEmphasized a, M3ECustomEmphasized b, double t) => M3ECustomEmphasized(
    expressiveDisplayLarge: TextStyle.lerp(a.expressiveDisplayLarge, b.expressiveDisplayLarge, t)!,
    expressiveDisplayMedium: TextStyle.lerp(a.expressiveDisplayMedium, b.expressiveDisplayMedium, t)!,
    expressiveDisplaySmall: TextStyle.lerp(a.expressiveDisplaySmall, b.expressiveDisplaySmall, t)!,
    expressiveHeadlineLarge: TextStyle.lerp(a.expressiveHeadlineLarge, b.expressiveHeadlineLarge, t)!,
    expressiveHeadlineMedium: TextStyle.lerp(a.expressiveHeadlineMedium, b.expressiveHeadlineMedium, t)!,
    expressiveHeadlineSmall: TextStyle.lerp(a.expressiveHeadlineSmall, b.expressiveHeadlineSmall, t)!,
    expressiveTitleLarge: TextStyle.lerp(a.expressiveTitleLarge, b.expressiveTitleLarge, t)!,
    expressiveTitleMedium: TextStyle.lerp(a.expressiveTitleMedium, b.expressiveTitleMedium, t)!,
    expressiveTitleSmall: TextStyle.lerp(a.expressiveTitleSmall, b.expressiveTitleSmall, t)!,
    expressiveBodyLarge: TextStyle.lerp(a.expressiveBodyLarge, b.expressiveBodyLarge, t)!,
    expressiveBodyMedium: TextStyle.lerp(a.expressiveBodyMedium, b.expressiveBodyMedium, t)!,
    expressiveBodySmall: TextStyle.lerp(a.expressiveBodySmall, b.expressiveBodySmall, t)!,
    expressiveLabelLarge: TextStyle.lerp(a.expressiveLabelLarge, b.expressiveLabelLarge, t)!,
    expressiveLabelMedium: TextStyle.lerp(a.expressiveLabelMedium, b.expressiveLabelMedium, t)!,
    expressiveLabelSmall: TextStyle.lerp(a.expressiveLabelSmall, b.expressiveLabelSmall, t)!,
  );
}