Typography

The typographic scale used by Catalyst components.

Create a Typography and pass it to ThemeData to customise the font family, sizes, weights, and individual styles. Typography supports three levels of customisation, in ascending specificity:

1. fontFamily — applies to all non-overridden body styles (p1, p2, body, p3, caption, micro). Defaults to null, which lets Flutter fall through to the platform default.
2. headerFontFamily — applies to heading styles (display, h1, h2, h3); falls back to fontFamily when null, so you only need to set it when headers should use a different typeface.
3. Per-style TextStyle overrides — individual constructor parameters (display:, h1:, h2:, h3:, p1:, p2:, body:, p3:, caption:, micro:) that replace the computed default for that slot entirely. Overridden styles are used verbatim — fontFamily, headerFontFamily, and colorScheme are not merged into them.

Fields

Field	Type	Description
fontFamily	String?	Typeface for body-level styles. null uses the platform default.
headerFontFamily	String?	Typeface for heading-level styles (display, h1, h2, h3). Falls back to fontFamily when null.
colorScheme	ColorScheme	Required. Binds the default text colour for non-overridden styles; set automatically when attached to a ThemeData.

Style getters

Each getter returns the explicit override if one was supplied to the constructor, otherwise a computed default built from _headerBase (heading styles) or _bodyBase (body styles):

Getter	Base	Size	Weight	Line height	Description
display	header	40 sp	FontWeight.w700	1	Hero numbers and large display text.
h1	header	28 sp	FontWeight.w600	1	Page-level heading.
h2	header	22 sp	FontWeight.w600	1	Section heading.
h3	header	18 sp	FontWeight.w500	1	Sub-section heading.
p1	body	20 sp	FontWeight.w500	1	Large paragraph text.
p2	body	18 sp	FontWeight.w400	1	Secondary paragraph text.
body	body	16 sp	FontWeight.w400	1	Default body copy.
p3	body	14 sp	FontWeight.w400	1	Supporting body copy.
caption	body	12 sp	FontWeight.w400	1	Captions and helper text.
micro	body	10 sp	FontWeight.w500	1	Micro labels and badges.

defaultStyle is an additional getter equal to body; it is used as the ambient DefaultTextStyle set up by the Theme widget.

_bodyBase and _headerBase are private getters — the two base TextStyle values that embed the appropriate font family and the colorScheme.text colour. headerFontFamily ?? fontFamily is used for _headerBase; fontFamily alone is used for _bodyBase.

Overriding

Single font family:

Typography(colorScheme: myScheme, fontFamily: 'Inter')

Different font families for headers and body:

Typography(
  colorScheme: myScheme,
  fontFamily: 'Inter',
  headerFontFamily: 'Playfair Display',
)

Override individual styles:

Typography(
  colorScheme: myScheme,
  display: TextStyle(fontSize: 48, fontWeight: FontWeight.w800),
  body: TextStyle(fontSize: 15, height: 1.6),
)

Override via an existing theme:

themeData.copyWith(
  typography: themeData.typography.copyWith(
    body: TextStyle(fontSize: 15, height: 1.6),
  ),
);

copyWith and withColorScheme both thread every field —fontFamily, headerFontFamily, and each per-style override — through to the new instance; withColorScheme additionally rebinds colorScheme while preserving every style override and font family setting.

ThemeData.light() and ThemeData.dark() build a default Typography internally from fontFamily when no explicit typography is supplied, then call withColorScheme to bind it to the resolved ColorScheme. See Context extensions for how components read the active Typography via context.typography.