| // Copyright 2014 The Flutter Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| import 'package:flutter/foundation.dart'; |
| import 'package:flutter/painting.dart'; |
| |
| import 'typography.dart'; |
| |
| /// Material design text theme. |
| /// |
| /// Definitions for the various typographical styles found in Material Design |
| /// (e.g., button, caption). Rather than creating a [TextTheme] directly, |
| /// you can obtain an instance as [Typography.black] or [Typography.white]. |
| /// |
| /// To obtain the current text theme, call [Theme.of] with the current |
| /// [BuildContext] and read the [ThemeData.textTheme] property. |
| /// |
| /// The names of the TextTheme properties match this table from the |
| /// [Material Design spec](https://material.io/design/typography/the-type-system.html#type-scale) |
| /// with two exceptions: the styles called H1-H6 in the spec are |
| /// headline1-headline6 in the API, and body1,body2 are called |
| /// bodyText1 and bodyText2. |
| /// |
| ///  |
| /// |
| /// The Material Design typography scheme was significantly changed in the |
| /// current (2018) version of the specification |
| /// ([https://material.io/design/typography](https://material.io/design/typography)). |
| /// |
| /// The 2018 spec has thirteen text styles: |
| /// ``` |
| /// NAME SIZE WEIGHT SPACING |
| /// headline1 96.0 light -1.5 |
| /// headline2 60.0 light -0.5 |
| /// headline3 48.0 regular 0.0 |
| /// headline4 34.0 regular 0.25 |
| /// headline5 24.0 regular 0.0 |
| /// headline6 20.0 medium 0.15 |
| /// subtitle1 16.0 regular 0.15 |
| /// subtitle2 14.0 medium 0.1 |
| /// body1 16.0 regular 0.5 (bodyText1) |
| /// body2 14.0 regular 0.25 (bodyText2) |
| /// button 14.0 medium 1.25 |
| /// caption 12.0 regular 0.4 |
| /// overline 10.0 regular 1.5 |
| /// ``` |
| /// |
| /// ...where "light" is `FontWeight.w300`, "regular" is `FontWeight.w400` and |
| /// "medium" is `FontWeight.w500`. |
| /// |
| /// By default, text styles are initialized to match the 2018 Material Design |
| /// specification as listed above. To provide backwards compatibility, the 2014 |
| /// specification is also available. |
| /// |
| /// To explicitly configure a [Theme] for the 2018 sizes, weights, and letter |
| /// spacings, you can initialize its [ThemeData.typography] value using |
| /// [Typography.material2018]. The [Typography] constructor defaults to this |
| /// configuration. To configure a [Theme] for the 2014 sizes, weights, and letter |
| /// spacings, initialize its [ThemeData.typography] value using |
| /// [Typography.material2014]. |
| /// |
| /// See also: |
| /// |
| /// * [Typography], the class that generates [TextTheme]s appropriate for a platform. |
| /// * [Theme], for other aspects of a material design application that can be |
| /// globally adjusted, such as the color scheme. |
| /// * <https://material.io/design/typography/> |
| @immutable |
| class TextTheme with Diagnosticable { |
| /// Creates a text theme that uses the given values. |
| /// |
| /// Rather than creating a new text theme, consider using [Typography.black] |
| /// or [Typography.white], which implement the typography styles in the |
| /// material design specification: |
| /// |
| /// <https://material.io/design/typography/#type-scale> |
| /// |
| /// If you do decide to create your own text theme, consider using one of |
| /// those predefined themes as a starting point for [copyWith] or [apply]. |
| const TextTheme({ |
| this.headline1, |
| this.headline2, |
| this.headline3, |
| this.headline4, |
| this.headline5, |
| this.headline6, |
| this.subtitle1, |
| this.subtitle2, |
| this.bodyText1, |
| this.bodyText2, |
| this.caption, |
| this.button, |
| this.overline, |
| }); |
| |
| /// Extremely large text. |
| final TextStyle? headline1; |
| |
| /// Very, very large text. |
| /// |
| /// Used for the date in the dialog shown by [showDatePicker]. |
| final TextStyle? headline2; |
| |
| /// Very large text. |
| final TextStyle? headline3; |
| |
| /// Large text. |
| final TextStyle? headline4; |
| |
| /// Used for large text in dialogs (e.g., the month and year in the dialog |
| /// shown by [showDatePicker]). |
| final TextStyle? headline5; |
| |
| /// Used for the primary text in app bars and dialogs (e.g., [AppBar.title] |
| /// and [AlertDialog.title]). |
| final TextStyle? headline6; |
| |
| /// Used for the primary text in lists (e.g., [ListTile.title]). |
| final TextStyle? subtitle1; |
| |
| /// For medium emphasis text that's a little smaller than [subtitle1]. |
| final TextStyle? subtitle2; |
| |
| /// Used for emphasizing text that would otherwise be [bodyText2]. |
| final TextStyle? bodyText1; |
| |
| /// The default text style for [Material]. |
| final TextStyle? bodyText2; |
| |
| /// Used for auxiliary text associated with images. |
| final TextStyle? caption; |
| |
| /// Used for text on [ElevatedButton], [TextButton] and [OutlinedButton]. |
| final TextStyle? button; |
| |
| /// The smallest style. |
| /// |
| /// Typically used for captions or to introduce a (larger) headline. |
| final TextStyle? overline; |
| |
| /// Creates a copy of this text theme but with the given fields replaced with |
| /// the new values. |
| /// |
| /// Consider using [Typography.black] or [Typography.white], which implement |
| /// the typography styles in the material design specification, as a starting |
| /// point. |
| /// |
| /// {@tool snippet} |
| /// |
| /// ```dart |
| /// /// A Widget that sets the ambient theme's title text color for its |
| /// /// descendants, while leaving other ambient theme attributes alone. |
| /// class TitleColorThemeCopy extends StatelessWidget { |
| /// const TitleColorThemeCopy({Key? key, required this.child, required this.titleColor}) : super(key: key); |
| /// |
| /// final Color titleColor; |
| /// final Widget child; |
| /// |
| /// @override |
| /// Widget build(BuildContext context) { |
| /// final ThemeData theme = Theme.of(context); |
| /// return Theme( |
| /// data: theme.copyWith( |
| /// textTheme: theme.textTheme.copyWith( |
| /// headline6: theme.textTheme.headline6!.copyWith( |
| /// color: titleColor, |
| /// ), |
| /// ), |
| /// ), |
| /// child: child, |
| /// ); |
| /// } |
| /// } |
| /// ``` |
| /// {@end-tool} |
| /// |
| /// See also: |
| /// |
| /// * [merge] is used instead of [copyWith] when you want to merge all |
| /// of the fields of a TextTheme instead of individual fields. |
| TextTheme copyWith({ |
| TextStyle? headline1, |
| TextStyle? headline2, |
| TextStyle? headline3, |
| TextStyle? headline4, |
| TextStyle? headline5, |
| TextStyle? headline6, |
| TextStyle? subtitle1, |
| TextStyle? subtitle2, |
| TextStyle? bodyText1, |
| TextStyle? bodyText2, |
| TextStyle? caption, |
| TextStyle? button, |
| TextStyle? overline, |
| }) { |
| return TextTheme( |
| headline1: headline1 ?? this.headline1, |
| headline2: headline2 ?? this.headline2, |
| headline3: headline3 ?? this.headline3, |
| headline4: headline4 ?? this.headline4, |
| headline5: headline5 ?? this.headline5, |
| headline6: headline6 ?? this.headline6, |
| subtitle1: subtitle1 ?? this.subtitle1, |
| subtitle2: subtitle2 ?? this.subtitle2, |
| bodyText1: bodyText1 ?? this.bodyText1, |
| bodyText2: bodyText2 ?? this.bodyText2, |
| caption: caption ?? this.caption, |
| button: button ?? this.button, |
| overline: overline ?? this.overline, |
| ); |
| } |
| |
| /// Creates a new [TextTheme] where each text style from this object has been |
| /// merged with the matching text style from the `other` object. |
| /// |
| /// The merging is done by calling [TextStyle.merge] on each respective pair |
| /// of text styles from this and the [other] text themes and is subject to |
| /// the value of [TextStyle.inherit] flag. For more details, see the |
| /// documentation on [TextStyle.merge] and [TextStyle.inherit]. |
| /// |
| /// If this theme, or the `other` theme has members that are null, then the |
| /// non-null one (if any) is used. If the `other` theme is itself null, then |
| /// this [TextTheme] is returned unchanged. If values in both are set, then |
| /// the values are merged using [TextStyle.merge]. |
| /// |
| /// This is particularly useful if one [TextTheme] defines one set of |
| /// properties and another defines a different set, e.g. having colors |
| /// defined in one text theme and font sizes in another, or when one |
| /// [TextTheme] has only some fields defined, and you want to define the rest |
| /// by merging it with a default theme. |
| /// |
| /// {@tool snippet} |
| /// |
| /// ```dart |
| /// /// A Widget that sets the ambient theme's title text color for its |
| /// /// descendants, while leaving other ambient theme attributes alone. |
| /// class TitleColorTheme extends StatelessWidget { |
| /// const TitleColorTheme({Key? key, required this.child, required this.titleColor}) : super(key: key); |
| /// |
| /// final Color titleColor; |
| /// final Widget child; |
| /// |
| /// @override |
| /// Widget build(BuildContext context) { |
| /// ThemeData theme = Theme.of(context); |
| /// // This partialTheme is incomplete: it only has the title style |
| /// // defined. Just replacing theme.textTheme with partialTheme would |
| /// // set the title, but everything else would be null. This isn't very |
| /// // useful, so merge it with the existing theme to keep all of the |
| /// // preexisting definitions for the other styles. |
| /// final TextTheme partialTheme = TextTheme(headline6: TextStyle(color: titleColor)); |
| /// theme = theme.copyWith(textTheme: theme.textTheme.merge(partialTheme)); |
| /// return Theme(data: theme, child: child); |
| /// } |
| /// } |
| /// ``` |
| /// {@end-tool} |
| /// |
| /// See also: |
| /// |
| /// * [copyWith] is used instead of [merge] when you wish to override |
| /// individual fields in the [TextTheme] instead of merging all of the |
| /// fields of two [TextTheme]s. |
| TextTheme merge(TextTheme? other) { |
| if (other == null) |
| return this; |
| return copyWith( |
| headline1: headline1?.merge(other.headline1) ?? other.headline1, |
| headline2: headline2?.merge(other.headline2) ?? other.headline2, |
| headline3: headline3?.merge(other.headline3) ?? other.headline3, |
| headline4: headline4?.merge(other.headline4) ?? other.headline4, |
| headline5: headline5?.merge(other.headline5) ?? other.headline5, |
| headline6: headline6?.merge(other.headline6) ?? other.headline6, |
| subtitle1: subtitle1?.merge(other.subtitle1) ?? other.subtitle1, |
| subtitle2: subtitle2?.merge(other.subtitle2) ?? other.subtitle2, |
| bodyText1: bodyText1?.merge(other.bodyText1) ?? other.bodyText1, |
| bodyText2: bodyText2?.merge(other.bodyText2) ?? other.bodyText2, |
| caption: caption?.merge(other.caption) ?? other.caption, |
| button: button?.merge(other.button) ?? other.button, |
| overline: overline?.merge(other.overline) ?? other.overline, |
| ); |
| } |
| |
| /// Creates a copy of this text theme but with the given field replaced in |
| /// each of the individual text styles. |
| /// |
| /// The `displayColor` is applied to [headline4], [headline3], [headline2], |
| /// [headline1], and [caption]. The `bodyColor` is applied to the remaining |
| /// text styles. |
| /// |
| /// Consider using [Typography.black] or [Typography.white], which implement |
| /// the typography styles in the material design specification, as a starting |
| /// point. |
| TextTheme apply({ |
| String? fontFamily, |
| double fontSizeFactor = 1.0, |
| double fontSizeDelta = 0.0, |
| Color? displayColor, |
| Color? bodyColor, |
| TextDecoration? decoration, |
| Color? decorationColor, |
| TextDecorationStyle? decorationStyle, |
| }) { |
| return TextTheme( |
| headline1: headline1?.apply( |
| color: displayColor, |
| decoration: decoration, |
| decorationColor: decorationColor, |
| decorationStyle: decorationStyle, |
| fontFamily: fontFamily, |
| fontSizeFactor: fontSizeFactor, |
| fontSizeDelta: fontSizeDelta, |
| ), |
| headline2: headline2?.apply( |
| color: displayColor, |
| decoration: decoration, |
| decorationColor: decorationColor, |
| decorationStyle: decorationStyle, |
| fontFamily: fontFamily, |
| fontSizeFactor: fontSizeFactor, |
| fontSizeDelta: fontSizeDelta, |
| ), |
| headline3: headline3?.apply( |
| color: displayColor, |
| decoration: decoration, |
| decorationColor: decorationColor, |
| decorationStyle: decorationStyle, |
| fontFamily: fontFamily, |
| fontSizeFactor: fontSizeFactor, |
| fontSizeDelta: fontSizeDelta, |
| ), |
| headline4: headline4?.apply( |
| color: displayColor, |
| decoration: decoration, |
| decorationColor: decorationColor, |
| decorationStyle: decorationStyle, |
| fontFamily: fontFamily, |
| fontSizeFactor: fontSizeFactor, |
| fontSizeDelta: fontSizeDelta, |
| ), |
| headline5: headline5?.apply( |
| color: bodyColor, |
| decoration: decoration, |
| decorationColor: decorationColor, |
| decorationStyle: decorationStyle, |
| fontFamily: fontFamily, |
| fontSizeFactor: fontSizeFactor, |
| fontSizeDelta: fontSizeDelta, |
| ), |
| headline6: headline6?.apply( |
| color: bodyColor, |
| decoration: decoration, |
| decorationColor: decorationColor, |
| decorationStyle: decorationStyle, |
| fontFamily: fontFamily, |
| fontSizeFactor: fontSizeFactor, |
| fontSizeDelta: fontSizeDelta, |
| ), |
| subtitle1: subtitle1?.apply( |
| color: bodyColor, |
| decoration: decoration, |
| decorationColor: decorationColor, |
| decorationStyle: decorationStyle, |
| fontFamily: fontFamily, |
| fontSizeFactor: fontSizeFactor, |
| fontSizeDelta: fontSizeDelta, |
| ), |
| subtitle2: subtitle2?.apply( |
| color: bodyColor, |
| decoration: decoration, |
| decorationColor: decorationColor, |
| decorationStyle: decorationStyle, |
| fontFamily: fontFamily, |
| fontSizeFactor: fontSizeFactor, |
| fontSizeDelta: fontSizeDelta, |
| ), |
| bodyText1: bodyText1?.apply( |
| color: bodyColor, |
| decoration: decoration, |
| decorationColor: decorationColor, |
| decorationStyle: decorationStyle, |
| fontFamily: fontFamily, |
| fontSizeFactor: fontSizeFactor, |
| fontSizeDelta: fontSizeDelta, |
| ), |
| bodyText2: bodyText2?.apply( |
| color: bodyColor, |
| decoration: decoration, |
| decorationColor: decorationColor, |
| decorationStyle: decorationStyle, |
| fontFamily: fontFamily, |
| fontSizeFactor: fontSizeFactor, |
| fontSizeDelta: fontSizeDelta, |
| ), |
| caption: caption?.apply( |
| color: displayColor, |
| decoration: decoration, |
| decorationColor: decorationColor, |
| decorationStyle: decorationStyle, |
| fontFamily: fontFamily, |
| fontSizeFactor: fontSizeFactor, |
| fontSizeDelta: fontSizeDelta, |
| ), |
| button: button?.apply( |
| color: bodyColor, |
| decoration: decoration, |
| decorationColor: decorationColor, |
| decorationStyle: decorationStyle, |
| fontFamily: fontFamily, |
| fontSizeFactor: fontSizeFactor, |
| fontSizeDelta: fontSizeDelta, |
| ), |
| overline: overline?.apply( |
| color: bodyColor, |
| decoration: decoration, |
| decorationColor: decorationColor, |
| decorationStyle: decorationStyle, |
| fontFamily: fontFamily, |
| fontSizeFactor: fontSizeFactor, |
| fontSizeDelta: fontSizeDelta, |
| ), |
| ); |
| } |
| |
| /// Linearly interpolate between two text themes. |
| /// |
| /// {@macro dart.ui.shadow.lerp} |
| static TextTheme lerp(TextTheme? a, TextTheme? b, double t) { |
| assert(t != null); |
| return TextTheme( |
| headline1: TextStyle.lerp(a?.headline1, b?.headline1, t), |
| headline2: TextStyle.lerp(a?.headline2, b?.headline2, t), |
| headline3: TextStyle.lerp(a?.headline3, b?.headline3, t), |
| headline4: TextStyle.lerp(a?.headline4, b?.headline4, t), |
| headline5: TextStyle.lerp(a?.headline5, b?.headline5, t), |
| headline6: TextStyle.lerp(a?.headline6, b?.headline6, t), |
| subtitle1: TextStyle.lerp(a?.subtitle1, b?.subtitle1, t), |
| subtitle2: TextStyle.lerp(a?.subtitle2, b?.subtitle2, t), |
| bodyText1: TextStyle.lerp(a?.bodyText1, b?.bodyText1, t), |
| bodyText2: TextStyle.lerp(a?.bodyText2, b?.bodyText2, t), |
| caption: TextStyle.lerp(a?.caption, b?.caption, t), |
| button: TextStyle.lerp(a?.button, b?.button, t), |
| overline: TextStyle.lerp(a?.overline, b?.overline, t), |
| ); |
| } |
| |
| @override |
| bool operator ==(Object other) { |
| if (identical(this, other)) |
| return true; |
| if (other.runtimeType != runtimeType) |
| return false; |
| return other is TextTheme |
| && headline1 == other.headline1 |
| && headline2 == other.headline2 |
| && headline3 == other.headline3 |
| && headline4 == other.headline4 |
| && headline5 == other.headline5 |
| && headline6 == other.headline6 |
| && subtitle1 == other.subtitle1 |
| && subtitle2 == other.subtitle2 |
| && bodyText1 == other.bodyText1 |
| && bodyText2 == other.bodyText2 |
| && caption == other.caption |
| && button == other.button |
| && overline == other.overline; |
| } |
| |
| @override |
| int get hashCode { |
| // The hashValues() function supports up to 20 arguments. |
| return hashValues( |
| headline1, |
| headline2, |
| headline3, |
| headline4, |
| headline5, |
| headline6, |
| subtitle1, |
| subtitle2, |
| bodyText1, |
| bodyText2, |
| caption, |
| button, |
| overline, |
| ); |
| } |
| |
| @override |
| void debugFillProperties(DiagnosticPropertiesBuilder properties) { |
| super.debugFillProperties(properties); |
| final TextTheme defaultTheme = Typography.material2018(platform: defaultTargetPlatform).black; |
| properties.add(DiagnosticsProperty<TextStyle>('headline1', headline1, defaultValue: defaultTheme.headline1)); |
| properties.add(DiagnosticsProperty<TextStyle>('headline2', headline2, defaultValue: defaultTheme.headline2)); |
| properties.add(DiagnosticsProperty<TextStyle>('headline3', headline3, defaultValue: defaultTheme.headline3)); |
| properties.add(DiagnosticsProperty<TextStyle>('headline4', headline4, defaultValue: defaultTheme.headline4)); |
| properties.add(DiagnosticsProperty<TextStyle>('headline5', headline5, defaultValue: defaultTheme.headline5)); |
| properties.add(DiagnosticsProperty<TextStyle>('headline6', headline6, defaultValue: defaultTheme.headline6)); |
| properties.add(DiagnosticsProperty<TextStyle>('subtitle1', subtitle1, defaultValue: defaultTheme.subtitle1)); |
| properties.add(DiagnosticsProperty<TextStyle>('subtitle2', subtitle2, defaultValue: defaultTheme.subtitle2)); |
| properties.add(DiagnosticsProperty<TextStyle>('bodyText1', bodyText1, defaultValue: defaultTheme.bodyText1)); |
| properties.add(DiagnosticsProperty<TextStyle>('bodyText2', bodyText2, defaultValue: defaultTheme.bodyText2)); |
| properties.add(DiagnosticsProperty<TextStyle>('caption', caption, defaultValue: defaultTheme.caption)); |
| properties.add(DiagnosticsProperty<TextStyle>('button', button, defaultValue: defaultTheme.button)); |
| properties.add(DiagnosticsProperty<TextStyle>('overline', overline, defaultValue: defaultTheme.overline)); |
| } |
| } |
