FontFeature class Null safety

A feature tag and value that affect the selection of glyphs in a font.

Different fonts support different features. Consider using a tool such as wakamaifondue.com/ to examine your fonts to determine what features are available.

This example shows usage of several OpenType font features, including Small Caps (selected manually using the "smcp" code), old-style figures, fractional ligatures, and stylistic sets.
To create a local project with this code sample, run:
flutter create --sample=dart.dart_ui.FontFeature.1 mysample
import 'dart:ui';

import 'package:flutter/material.dart';

void main() => runApp(const ExampleApp());

class ExampleApp extends StatelessWidget {
  const ExampleApp({super.key});

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      home: ExampleWidget(),
    );
  }
}

final TextStyle titleStyle = TextStyle(
  fontSize: 18,
  fontFeatures: const <FontFeature>[FontFeature.enable('smcp')],
  color: Colors.blueGrey[600],
);

class ExampleWidget extends StatelessWidget {
  const ExampleWidget({super.key});

  @override
  Widget build(BuildContext context) {
    // The Cardo, Milonga and Raleway Dots fonts can be downloaded from
    // Google Fonts (https://www.google.com/fonts).
    return Scaffold(
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            const Spacer(flex: 5),
            Text('regular numbers have their place:', style: titleStyle),
            const Text('The 1972 cup final was a 1-1 draw.',
                style: TextStyle(
                  fontFamily: 'Cardo',
                  fontSize: 24,
                )),
            const Spacer(),
            Text('but old-style figures blend well with lower case:',
                style: titleStyle),
            const Text('The 1972 cup final was a 1-1 draw.',
                style: TextStyle(
                    fontFamily: 'Cardo',
                    fontSize: 24,
                    fontFeatures: <FontFeature>[
                      FontFeature.oldstyleFigures()
                    ])),
            const Spacer(),
            const Divider(),
            const Spacer(),
            Text('fractions look better with a custom ligature:',
                style: titleStyle),
            const Text('Add 1/2 tsp of flour and stir.',
                style: TextStyle(
                    fontFamily: 'Milonga',
                    fontSize: 24,
                    fontFeatures: <FontFeature>[
                      FontFeature.alternativeFractions()
                    ])),
            const Spacer(),
            const Divider(),
            const Spacer(),
            Text('multiple stylistic sets in one font:', style: titleStyle),
            const Text('Raleway Dots',
                style: TextStyle(fontFamily: 'Raleway Dots', fontSize: 48)),
            Text('Raleway Dots',
                style: TextStyle(
                  fontFeatures: <FontFeature>[FontFeature.stylisticSet(1)],
                  fontFamily: 'Raleway Dots',
                  fontSize: 48,
                )),
            const Spacer(flex: 5),
          ],
        ),
      ),
    );
  }
}

See also:

Constructors

FontFeature(String feature, [int value = 1])
Creates a FontFeature object, which can be added to a TextStyle to change how the engine selects glyphs when rendering text.
const
FontFeature.alternative(int value)
Access alternative glyphs. (aalt)
const
FontFeature.alternativeFractions()
Use alternative ligatures to represent fractions. (afrc)
const
FontFeature.caseSensitiveForms()
Enable case-sensitive forms. (case)
const
FontFeature.characterVariant(int value)
Select a character variant. (cv01 through cv99)
factory
FontFeature.contextualAlternates()
Enable contextual alternates. (calt)
const
FontFeature.denominator()
Display digits as denominators. (dnom)
const
FontFeature.disable(String feature)
Create a FontFeature object that disables the feature with the given tag.
const
FontFeature.enable(String feature)
Create a FontFeature object that enables the feature with the given tag.
const
FontFeature.fractions()
Use ligatures to represent fractions. (afrc)
const
FontFeature.historicalForms()
Use historical forms. (hist)
const
FontFeature.historicalLigatures()
Use historical ligatures. (hlig)
const
FontFeature.liningFigures()
Use lining figures. (lnum)
const
FontFeature.localeAware({bool enable = true})
Use locale-specific glyphs. (locl)
const
FontFeature.notationalForms([int value = 1])
Display alternative glyphs for numerals (alternate annotation forms). (nalt)
const
FontFeature.numerators()
Display digits as numerators. (numr)
const
FontFeature.oldstyleFigures()
Use old style figures. (onum)
const
FontFeature.ordinalForms()
Use ordinal forms for alphabetic glyphs. (ordn)
const
FontFeature.proportionalFigures()
Use proportional (varying width) figures. (pnum)
const
FontFeature.randomize()
Randomize the alternate forms used in text. (rand)
const
FontFeature.scientificInferiors()
Use scientific inferiors. (sinf)
const
FontFeature.slashedZero()
Use the slashed zero. (zero)
const
FontFeature.stylisticAlternates()
Enable stylistic alternates. (salt)
const
FontFeature.stylisticSet(int value)
Select a stylistic set. (ss01 through ss20)
factory
FontFeature.subscripts()
Enable subscripts. (subs)
const
FontFeature.superscripts()
Enable superscripts. (sups)
const
FontFeature.swash([int value = 1])
Enable swash glyphs. (swsh)
const
FontFeature.tabularFigures()
Use tabular (monospace) figures. (tnum)
const

Properties

feature String
The tag that identifies the effect of this feature. Must consist of 4 ASCII characters (typically lowercase letters).
final
hashCode int
The hash code for this object.
read-only, override
runtimeType Type
A representation of the runtime type of the object.
read-only, inherited
value int
The value assigned to this feature.
final

Methods

noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed.
inherited
toString() String
A string representation of this object.
override

Operators

operator ==(Object other) bool
The equality operator.
override