---
title: "TextAutoSize"
description: "Interface used by Text composables to override text size to automatically grow or shrink text to
fill the layout bounds."
type: "interface"
---

<div class='type'>Interface</div>


<a id='references'></a>

<div class='sourceset sourceset-common'>Common</div>



```kotlin
interface TextAutoSize
```


Interface used by Text composables to override text size to automatically grow or shrink text to
fill the layout bounds.


## Functions

```kotlin
fun TextAutoSizeLayoutScope.getFontSize(
        constraints: Constraints,
        text: AnnotatedString,
    ): TextUnit
```


Calculates font size and provides access to `TextAutoSizeLayoutScope`, which offers
`TextAutoSizeLayoutScope.performLayout` to lay out the text and use the measured size.

#### Returns

| | |
| --- | --- |
|  | The derived optimal font size |



```kotlin
override fun equals(other: Any?): Boolean
```


This type is used in performance-sensitive paths and requires providing equality guarantees.
Using a data class is sufficient. Singletons may implement this function with referential
equality (`this === other`). Instances with no properties may implement this function by
checking the type of the other object.

#### Returns

| | |
| --- | --- |
|  | true if both AutoSize instances are identical. |



```kotlin
override fun hashCode(): Int
```


This type is used in performance-sensitive paths and requires providing identity guarantees.

#### Returns

| | |
| --- | --- |
|  | a unique hashcode for this AutoSize instance. |




## Code Examples

### TextAutoSizeBasicTextSample
```kotlin
/** Sample of using [TextAutoSize.StepBased] to auto-size text. */
@Composable
fun TextAutoSizeBasicTextSample() {
    Box(modifier = Modifier.size(200.dp)) {
        // The text will find the biggest available font size that fits in the box.
        BasicText(text = "Hello World", autoSize = TextAutoSize.StepBased())
    }
}
```