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📚 Contents

• Why auto_size_text_kit?
• Switching from auto_size_text
• Quick start
• How the font size is picked
• Gradient and outline
• Same size in a group
• Rich text
• When the text doesn't fit
• Rows, tables and IntrinsicHeight
• All parameters
• Platforms

✨ Why auto_size_text_kit?

auto_size_text_kit keeps the API of auto_size_text, so your code stays the same. Inside, it is built as a single render object that measures and paints the text in one place, which is what makes the extras below possible:

🎯 Measures what it paints	The size is picked with exactly the same text layout that is painted, so text isn't cut off when bold text is on or the alignment and direction differ
🌈 Gradient fill	Any Gradient, stretched across the lines of text
✏️ Outline	A solid or gradient outline, taken into account while fitting
📐 Works where layout measures first	IntrinsicHeight, IntrinsicWidth, Table, DataTable, baseline rows
👯 Groups without flicker	Texts in a group are painted at the shared size from the first frame
🔍 Accessible text scaling	Uses TextScaler, including Android 14's nonlinear font scaling
🧹 No leaks	Every text painter is disposed
⚡ Fits once	The size is only picked again when its text, style or space changes, not on every rebuild or color change
📦 No dependencies	Only Flutter itself

🔁 Switching from auto_size_text

Change the dependency and the import. Everything else stays the same.

dependencies:
  auto_size_text_kit: ^0.1.0

// Before
import 'package:auto_size_text/auto_size_text.dart';

// After
import 'package:auto_size_text_kit/auto_size_text_kit.dart';

AutoSizeText, AutoSizeText.rich and AutoSizeGroup take the same arguments. A few things behave differently:

	auto_size_text 3.0.0	auto_size_text_kit
minFontSize and maxFontSize	Must be multiples of stepGranularity (checked by an assertion)	Any value
Style smaller than minFontSize	Grows to minFontSize	Stays at the style's size
textScaleFactor	Supported	Still works, but deprecated: use textScaler
Bold text setting (iOS and Android)	Measured as regular, painted bold	Measured and painted bold
Inside IntrinsicHeight or DataTable	Not supported: it uses a LayoutBuilder, which can't report intrinsic sizes	Works
Reading the font size	No API for it	AutoSizeGroup.fontSize

The one difference to know: textKey now finds the widget that lays out the text instead of a Text widget, since there is no Text inside.

Switching file by file? Both packages use the same class names, so a file that imports both gets an "imported from both" error. Hide the old names in that file until you remove auto_size_text:

import 'package:auto_size_text/auto_size_text.dart'
    hide AutoSizeText, AutoSizeGroup;
import 'package:auto_size_text_kit/auto_size_text_kit.dart';

🚀 Quick start

import 'package:auto_size_text_kit/auto_size_text_kit.dart';

SizedBox(
  width: 200,
  child: AutoSizeText(
    'The quick brown fox jumps over the lazy dog',
    style: TextStyle(fontSize: 30),
    maxLines: 2,
  ),
)

The text starts at 30 and gets smaller until it fits in two lines of 200 pixels.

Tip: AutoSizeText needs a limit to fit into. Give it a width (a SizedBox, Expanded or Flexible), and a maxLines or a height. Without any limit, the text simply stays at its style's size.

📏 How the font size is picked

1. The text starts at the font size of its style, or maxFontSize if that's smaller.
2. If it doesn't fit the width, the height and maxLines, it tries smaller sizes, going down in steps of stepGranularity (1 by default).
3. It stops at minFontSize (12 by default). If the text still doesn't fit, overflow or overflowReplacement decide what happens.

The biggest size that fits is found with a binary search, so even a big range takes only a few measurements.

AutoSizeText(
  'Welcome back',
  style: TextStyle(fontSize: 40),
  minFontSize: 18,     // never smaller than 18
  maxFontSize: 32,     // never bigger than 32, even though the style says 40
  stepGranularity: 2,  // 18, 20, 22, ...
  maxLines: 1,
)

Only some sizes allowed? Pass them from biggest to smallest. The first one that fits is used:

AutoSizeText(
  'Welcome back',
  presetFontSizes: [40, 28, 20, 14],
  maxLines: 1,
)

Don't want words split across lines? By default, a word too long for a line on its own is broken, like Text does. With wrapWords: false, the text shrinks until every word fits on a line instead:

AutoSizeText('Supercalifragilistic', maxLines: 2, wrapWords: false)

Accessibility. The user's text size setting is applied on top of the picked size, and also scales minFontSize, maxFontSize and presetFontSizes. Pass textScaler to override it.

🌈 Gradient and outline

AutoSizeText(
  'SUMMER SALE',
  style: TextStyle(fontSize: 64, fontWeight: FontWeight.w900),
  maxLines: 1,
  gradient: LinearGradient(colors: [Color(0xFFFFD54F), Color(0xFFFF6F61)]),
  strokeWidth: 3,
  strokeColor: Colors.white,
)

• gradient fills the text with any Gradient: linear, radial or sweep. It stretches across the lines of text, not the whole box, so short centered text still shows every color.
• strokeWidth draws an outline that thick around every letter. The outline sits outside the letters and is part of the text's size, so a fitted text with an outline is never cut off.
• strokeColor colors the outline (black by default), or strokeGradient fills it with a gradient.
• Shadows in the style are drawn under the outline.

Numbers are where this shines: prices, scores and stats. Put them in a group so they share one size:

final group = AutoSizeGroup();
const style = TextStyle(fontSize: 48, fontWeight: FontWeight.w900);

Row(
  // An outline takes space like a border, so outlined numbers are a little
  // taller. Aligning on the baseline lines the digits up.
  crossAxisAlignment: CrossAxisAlignment.baseline,
  textBaseline: TextBaseline.alphabetic,
  children: [
    // Gradient and outline
    Expanded(
      child: AutoSizeText(
        '2,480',
        group: group,
        style: style,
        maxLines: 1,
        gradient: LinearGradient(colors: [Colors.amber, Colors.orange]),
        strokeWidth: 2,
        strokeColor: Colors.white,
      ),
    ),
    // Outline only: a transparent fill leaves just the outline
    Expanded(
      child: AutoSizeText(
        '98%',
        group: group,
        style: style.copyWith(color: Colors.transparent),
        maxLines: 1,
        strokeWidth: 2,
        strokeColor: Colors.tealAccent,
      ),
    ),
    // Gradient only
    Expanded(
      child: AutoSizeText(
        '4.9',
        group: group,
        style: style,
        maxLines: 1,
        gradient: LinearGradient(colors: [Colors.lightBlue, Colors.purple]),
      ),
    ),
  ],
)

With a transparent fill, the outline keeps the same thickness as on filled text.

Just want gradient or outlined text, without shrinking? Use it without limits (no maxLines, enough space), and it's regular styled text.

👯 Same size in a group

Texts that belong together, like buttons in a row, look odd at different sizes. Give them the same AutoSizeGroup, and all of them use the size of the one that needs the smallest:

final group = AutoSizeGroup();

Row(
  children: [
    for (final label in ['OK', 'Save', 'Publish'])
      Expanded(
        child: FilledButton(
          onPressed: () {},
          child: AutoSizeText(label, group: group, maxLines: 1),
        ),
      ),
  ],
)

Create the group once in a State, not in build, and dispose it with the state:

class _MyPageState extends State<MyPage> {
  final _group = AutoSizeGroup();

  @override
  void dispose() {
    _group.dispose();
    super.dispose();
  }

  // ... pass _group to your AutoSizeTexts in build.
}

Reading the size. The group tells you the size it picked, so you can size an icon to match, for example:

ListenableBuilder(
  listenable: group,
  builder: (context, _) => Icon(Icons.check, size: group.fontSize ?? 24),
)

fontSize is the size before the user's text scale. Use a group with a single text to read the size of that text.

✍️ Rich text

AutoSizeText.rich shrinks the whole text together, so parts with different sizes keep their proportions:

AutoSizeText.rich(
  TextSpan(children: [
    TextSpan(text: '\$1,299'),
    TextSpan(
      text: ' / month',
      style: TextStyle(fontSize: 24, color: Colors.grey),
    ),
  ]),
  style: TextStyle(fontSize: 56, fontWeight: FontWeight.w800),
  maxLines: 1,
)

Tap recognizers on spans keep working. A gradient fills every part that has no color of its own; spans with a color, like ' / month' above, keep it. WidgetSpans aren't supported.

🙈 When the text doesn't fit

Even at minFontSize some text is too long. overflow works like on Text:

AutoSizeText(
  'A very long product name that never fits',
  maxLines: 1,
  minFontSize: 14,
  overflow: TextOverflow.ellipsis, // or clip, fade, visible
)

Or show a different widget instead:

AutoSizeText(
  user.fullName,
  maxLines: 1,
  minFontSize: 16,
  overflowReplacement: Text(user.initials),
)

📐 Rows, tables and IntrinsicHeight

• In a Row, wrap the text in Expanded or Flexible. Otherwise the row gives it unlimited width, and it never has to shrink.
• IntrinsicHeight, IntrinsicWidth, Table and DataTable measure their children before laying them out. That works: the text reports the height it will have at the size it will pick.
• Baseline alignment in rows works too.

🧾 All parameters

Everything the package gives you:

API	What it is
AutoSizeText('text', ...)	Auto-sizing text from a String
AutoSizeText.rich(TextSpan(...), ...)	Auto-sizing text from a TextSpan, for mixed styles
AutoSizeGroup()	Keeps several texts at the same size
group.fontSize	The size the group picked, or null while it's empty
group.addListener(...)	Called when fontSize changes (it's a ChangeNotifier)
group.dispose()	Frees the group when you're done with it

AutoSizeText and AutoSizeText.rich take the same parameters, the same as auto_size_text. The ones in bold are new:

Parameter	Default	What it does
style	DefaultTextStyle	Its font size is the biggest size the text is shown at
minFontSize	12	The smallest size the text shrinks to
maxFontSize	none	The biggest size, even if the style is bigger
stepGranularity	1	How much the size changes with each step
presetFontSizes	none	The only sizes allowed, biggest first
maxLines	DefaultTextStyle	The most lines the text may take
group	none	Keeps several texts at the same size
wrapWords	true	Whether a long word may be split across lines
overflow	DefaultTextStyle	What happens when it doesn't fit even at minFontSize
overflowReplacement	none	Shown instead when it doesn't fit
textScaler	MediaQuery	Scales the text for accessibility
textAlign, textDirection, locale, softWrap, strutStyle, semanticsLabel		Like on Text
textWidthBasis, textHeightBehavior		Like on Text
textScaleFactor	none	Deprecated, use textScaler. Still works
textKey	none	A key for the widget that lays out the text
gradient	none	Fills the text with a gradient
strokeWidth	0	Width of the outline around the text
strokeColor	black	Color of the outline
strokeGradient	none	Fills the outline with a gradient

📱 Platforms

Pure Dart with no dependencies besides Flutter, so it works everywhere Flutter runs: Android, iOS, web, macOS, Windows and Linux. Tested with widget tests and in the example app on the web (Chromium).

The example app in example/ shows every feature, with a slider to squeeze the space.

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API compatible with auto_size_text by Simon Leier, so switching takes one import. The code is written from scratch.

Found a bug or have an idea? Open an issue.

☕ Support

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