---
title: "TransformScope"
description: "Scope used for suspending transformation operations.

Implementers of this interface should override both [transformBy] and [transformByWithCentroid],
treating a call to [transformBy] as a call to [transformByWithCentroid] with a
[Offset.Unspecified] centroid. To maintain compatibility, the default implementation of
[transformByWithCentroid] will call [transformBy], dropping the centroid information.

Overriding the newer [transformByWithCentroid] and using the centroid, if specified, allows
implementing more natural transformations around the point where the transformation occurs."
type: "interface"
---

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


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

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



```kotlin
@JvmDefaultWithCompatibility
interface TransformScope
```


Scope used for suspending transformation operations.

Implementers of this interface should override both `transformBy` and `transformByWithCentroid`,
treating a call to `transformBy` as a call to `transformByWithCentroid` with a
`Offset.Unspecified` centroid. To maintain compatibility, the default implementation of
`transformByWithCentroid` will call `transformBy`, dropping the centroid information.

Overriding the newer `transformByWithCentroid` and using the centroid, if specified, allows
implementing more natural transformations around the point where the transformation occurs.


## Functions

```kotlin
fun transformBy(
        zoomChange: Float = 1f,
        panChange: Offset = Offset.Zero,
        rotationChange: Float = 0f,
    )
```


Attempts to transform by `zoomChange` in relative multiplied value, by `panChange` in pixels
and by `rotationChange` in degrees.

Prefer calling the version of transformBy by that takes a centroid Offset, especially if the
zooming or rotation should happen around a particular point. This allows for more natural
transformations around a specific point. If there is no appropriate Offset to use, you can
pass Offset.Unspecified.

Implementations of TransformScope need to support both for compatibility, and can be expected
to interpret calls to `transformBy` without a centroid as equivalent to a call to
`transformByWithCentroid` with an `Offset.Unspecified` centroid.

#### Parameters

| | |
| --- | --- |
| zoomChange | scale factor multiplier change for zoom |
| panChange | panning offset change, in `Offset` pixels |
| rotationChange | change of the rotation in degrees |



```kotlin
fun transformByWithCentroid(
        centroid: Offset = Offset.Unspecified,
        zoomChange: Float = 1f,
        panChange: Offset = Offset.Zero,
        rotationChange: Float = 0f,
    ) = transformBy(zoomChange = zoomChange, panChange = panChange, rotationChange = rotationChange)
```


Attempts to transform by `zoomChange` in relative multiplied value, by `panChange` in pixels
and by `rotationChange` in degrees.

The default implementation calls `transformBy`, dropping the `centroid`.

#### Parameters

| | |
| --- | --- |
| centroid | the centroid around which the transformation is occurring. This may be `Offset.Unspecified` if the transformation is not associated with any centroid. |
| zoomChange | scale factor multiplier change for zoom |
| panChange | panning offset change, in `Offset` pixels |
| rotationChange | change of the rotation in degrees |