Ecosyste.ms: Awesome

An open API service indexing awesome lists of open source software.

https://github.com/simc/auto_size_text

Flutter widget that automatically resizes text to fit perfectly within its bounds.
https://github.com/simc/auto_size_text

android flutter ios text

Last synced: about 2 months ago
JSON representation

Flutter widget that automatically resizes text to fit perfectly within its bounds.

Lists

README

        

# AutoSizeText

![GitHub Workflow Status](https://img.shields.io/github/workflow/status/leisim/auto_size_text/CI) [![codecov](https://codecov.io/gh/leisim/auto_size_text/branch/master/graph/badge.svg)](https://codecov.io/gh/leisim/auto_size_text) [![Version](https://img.shields.io/pub/v/auto_size_text.svg)](https://pub.dev/packages/auto_size_text) ![GitHub license](https://img.shields.io/badge/license-MIT-blue.svg?style=flat)

Flutter widget that automatically resizes text to fit perfectly within its bounds.

**Show some ❤️ and star the repo to support the project**

### Resources:
- [Documentation](https://pub.dev/documentation/auto_size_text/latest/auto_size_text/AutoSizeText-class.html)
- [Pub Package](https://pub.dev/packages/auto_size_text)
- [GitHub Repository](https://github.com/leisim/auto_size_text)
- [Online Demo](https://appetize.io/app/w352kxbnz51c6pfvxrdvxcb3xw?device=nexus5&scale=100&orientation=landscape&osVersion=8.1&deviceColor=black)

Also check out the blazing fast key-value store [hive](https://github.com/leisim/hive).

![](https://raw.githubusercontent.com/leisim/auto_size_text/master/.github/art/maxlines.gif)

## Contents

- [Usage](#usage)
- [maxLines](#maxlines)
- [minFontSize & maxFontSize](#minfontsize--maxfontsize)
- [group](#group)
- [stepGranularity](#stepgranularity)
- [presetFontSizes](#presetfontsizes)
- [overflowReplacement](#overflowreplacement)
- [Rich Text](#rich-text)
- [Parameters](#parameters)
- [Performance](#performance)
- [Troubleshooting](#roubleshooting)
- [Missing bounds](#missing-bounds)
- [MinFontSize too large](#minfontsize-too-large)

## Usage

`AutoSizeText` behaves exactly like a `Text`. The only difference is that it resizes text to fit within its bounds.

```dart
AutoSizeText(
'The text to display',
style: TextStyle(fontSize: 20),
maxLines: 2,
)
```
**Note:** `AutoSizeText` needs bounded constraints to resize the text. More info [here](#troubleshooting).

### maxLines

The `maxLines` parameter works like you are used to with the `Text` widget. If there is no `maxLines` parameter specified, the `AutoSizeText` only fits the text according to the available width and height.

```dart
AutoSizeText(
'A really long String',
style: TextStyle(fontSize: 30),
maxLines: 2,
)
```

*Sample above*

### minFontSize & maxFontSize

The `AutoSizeText` starts with `TextStyle.fontSize`. It measures the resulting text and rescales it to fit within its bonds. You can however set the allowed range of the resulting font size.

With `minFontSize` you can specify the smallest possible font size. If the text still doesn't fit, it will be handled according to `overflow`. The default `minFontSize` is `12`.

`maxFontSize` sets the largest possible font size. This is useful if the `TextStyle` inherits the font size and you want to constrain it.

```dart
AutoSizeText(
'A really long String',
style: TextStyle(fontSize: 30),
minFontSize: 18,
maxLines: 4,
overflow: TextOverflow.ellipsis,
)
```

![](https://raw.githubusercontent.com/leisim/auto_size_text/master/.github/art/minfontsize.gif)

### group

You can synchronize the font size of multiple `AutoSizeText`. They will fit their boundaries and all `AutoSizeText` in the same group have the same size. That means they adjust their font size to the group member with the smallest effective font size.

**Note:** If a `AutoSizeText` cannot adjust because of constraints like `minFontSize`, it won't have the same size as the other group members.

An instance of `AutoSizeGroup` represents one group. Pass this instance to all `AutoSizeText` you want to add to that group. You don't have to care about disposing the group if it is no longer needed.

**Important:** Please don't pass a new instance of `AutoSizeGroup` every build. In other words, save the `AutoSizeGroup` instance in a `StatefulWidget`, or use `AutoSizeGroupBuilder`.

```dart
var myGroup = AutoSizeGroup();

AutoSizeText(
'Text 1',
group: myGroup,
);

AutoSizeText(
'Text 2',
group: myGroup,
);
```

![](https://raw.githubusercontent.com/leisim/auto_size_text/master/.github/art/group.gif)

### stepGranularity

The `AutoSizeText` will try each font size, starting with `TextStyle.fontSize` until the text fits within its bounds.
`stepGranularity` specifies how much the font size is decreased each step. Usually, this value should not be below `1` for best performance.

```dart
AutoSizeText(
'A really long String',
style: TextStyle(fontSize: 40),
minFontSize: 10,
stepGranularity: 10,
maxLines: 4,
overflow: TextOverflow.ellipsis,
)
```

![](https://raw.githubusercontent.com/leisim/auto_size_text/master/.github/art/stepgranularity.gif)

### presetFontSizes

If you want to allow only specific font sizes, you can set them with `presetFontSizes`.
If `presetFontSizes` is set, `minFontSize`, `maxFontSize` and `stepGranularity` will be ignored.

```dart
AutoSizeText(
'A really long String',
presetFontSizes: [40, 20, 14],
maxLines: 4,
)
```

![](https://raw.githubusercontent.com/leisim/auto_size_text/master/.github/art/presetfontsizes.gif)

### overflowReplacement

If the text is overflowing and does not fit its bounds, this widget is displayed instead. This can be useful to prevent text being too small to read.

```dart
AutoSizeText(
'A String tool long to display without extreme scaling or overflow.',
maxLines: 1,
overflowReplacement: Text('Sorry String too long'),
)
```

![](https://raw.githubusercontent.com/leisim/auto_size_text/master/.github/art/overflowreplacement.gif)

## Rich Text

You can also use Rich Text (like different text styles or links) with `AutoSizeText`. Just use the `AutoSizeText.rich()` constructor
(which works exactly like the `Text.rich()` constructor).

The only thing you have to be aware of is how the font size calculation works: The `fontSize` in the `style`
parameter of `AutoSizeText` (or the inherited `fontSize` if none is set) is used as reference.

For example:
```dart
AutoSizeText.rich(
TextSpan(text: 'A really long String'),
style: TextStyle(fontSize: 20),
minFontSize: 5,
)
```
The text will be at least 1/4 of its original size (5 / 20 = 1/4).
But it does not mean that all `TextSpan`s have at least font size `5`.

![](https://raw.githubusercontent.com/leisim/auto_size_text/master/.github/art/maxlines_rich.gif)

## Parameters

| Parameter | Description |
|---|---|
| `key`* | Controls how one widget replaces another widget in the tree. |
| `textKey` | Sets the key for the resulting `Text` widget |
| `style`* | If non-null, the style to use for this text |
| `minFontSize` | The **minimum** text size constraint to be used when auto-sizing text.
*Is being ignored if `presetFontSizes` is set.* |
| `maxFontSize` | The **maximum** text size constraint to be used when auto-sizing text.
*Is being ignored if `presetFontSizes` is set.* |
| `stepGranularity` | The step size in which the font size is being adapted to constraints. |
| `presetFontSizes` | Predefines all the possible font sizes.
**Important:** `presetFontSizes` have to be in descending order. |
| `group` | Synchronizes the size of multiple `AutoSizeText`s |
| `textAlign`* | How the text should be aligned horizontally. |
| `textDirection`* | The directionality of the text. This decides how `textAlign` values like `TextAlign.start` and `TextAlign.end` are interpreted. |
| `locale`* | Used to select a font when the same Unicode character can be rendered differently, depending on the locale. |
| `softWrap`* | Whether the text should break at soft line breaks. |
| `wrapWords` | Whether words which don't fit in one line should be wrapped. *Defaults to `true` to behave like `Text`.* |
| `overflow`* | How visual overflow should be handled. |
| `overflowReplacement` | If the text is overflowing and does not fit its bounds, this widget is displayed instead. |
| `textScaleFactor`* | The number of font pixels for each logical pixel. Also affects `minFontSize`, `maxFontSize` and `presetFontSizes`. |
| `maxLines` | An optional maximum number of lines for the text to span. |
| `semanticsLabel`* | An alternative semantics label for this text. |

Parameters marked with \* behave exactly the same as in `Text`

## Performance

`AutoSizeText` is really fast. In fact, you can replace all your `Text` widgets with `AutoSizeText`.

Nevertheless you should not use an unreasonable high `fontSize` in your `TextStyle`. E.g. don't set the `fontSize` to `1000` if you know, that the text will never be larger than `30`.

If your font size has a very large range, consider increasing `stepGranularity`.

## Troubleshooting

### Missing bounds

If `AutoSizeText` overflows or does not resize the text, you should check if it has constrained width and height.

**Wrong** code:
```dart
Row(
children: [
AutoSizeText(
'Here is a very long text, which should be resized',
maxLines: 1,
),
],
)
```
Because `Row` and other widgets like `Container`, `Column` or `ListView` do not constrain their children, the text will overflow.
You can fix this by constraining the `AutoSizeText`. Wrap it with `Expanded` in case of `Row` and `Column` or use a `SizedBox` or another widget with fixed width (and height).

**Correct** code:
```dart
Row(
children: [
Expanded( // Constrains AutoSizeText to the width of the Row
child: AutoSizeText(
'Here is a very long text, which should be resized',
maxLines: 1,
)
),
],
)
}
```

Further explanation can be found [here](https://stackoverflow.com/a/53908204). If you still have problems, please [open an issue](https://github.com/leisim/auto_size_text/issues/new).

### MinFontSize too large

`AutoSizeText` does not resize text below the `minFontSize` which defaults to 12. This can happen very easily if you use `AutoSizeText.rich()`:

**Wrong** code:
```dart
AutoSizeText.rich(
TextSpan(
text: 'Text that will not be resized correctly in some cases',
style: TextStyle(fontSize: 200),
),
)
```
This rich text does not have a style so it will fall back to the default style (probably `fontSize = 14`). It has an implicit `minFontSize` of 12 that means it can be resized to 86% of its original size at the most (14 -> 12). Just set `minFontSize = 0` or add `style: TextStyle(fontSize: 200)` to the `AutoSizeText`.

**Note:** If you use the first option, you should also consider lowering `stepGranularity`. Otherwise the steps of resizing will be very large.

**Correct** code:
```dart
AutoSizeText.rich(
TextSpan(
text: 'Text that will be resized correctly',
style: TextStyle(fontSize: 200),
),
minFontSize: 0,
stepGranularity: 0.1,
)
```

## MIT License
```
Copyright (c) 2018 Simon Leier

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the 'Software'), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
```