---
title: "BoxScope"
description: "A BoxScope provides a scope for the children of [Box] and [BoxWithConstraints]."
type: "interface"
---

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


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

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



```kotlin
@LayoutScopeMarker
interface BoxScope
```


A BoxScope provides a scope for the children of `Box` and `BoxWithConstraints`.


## Functions

```kotlin
fun Modifier.align(alignment: Alignment): Modifier
```


Pull the content element to a specific `Alignment` within the `Box`. This alignment will have
priority over the `Box`'s `alignment` parameter.


```kotlin
fun Modifier.matchParentSize(): Modifier
```


Size the element to match the size of the `Box` after all other content elements have been
measured.

The element using this modifier does not take part in defining the size of the `Box`.
Instead, it matches the size of the `Box` after all other children (not using
matchParentSize() modifier) have been measured to obtain the `Box`'s size. In contrast, a
general-purpose `Modifier.fillMaxSize` modifier, which makes an element occupy all available
space, will take part in defining the size of the `Box`. Consequently, using it for an
element inside a `Box` will make the `Box` itself always fill the available space.