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# ImagePresentationEvents.TransitionStarted

A transition between two viewing modes has started for an image presentation component.

```
struct TransitionStarted
```

## Overview

Note that a `TransitionStarted` event is not triggered
for viewing mode changes that transition immediately to the new mode.
For instantaneous transitions, only a `TransitionCompleted` event is fired.

Use the `TransitionStarted` event as an opportunity to hide overlaid UI during an animated transition.
Update the content and location of that UI after the transition completes via a corresponding `TransitionCompleted` event.

## Topics

### Instance Properties

[`let currentViewingMode: ImagePresentationComponent.ViewingMode`](/documentation/RealityKit/ImagePresentationEvents/TransitionStarted/currentViewingMode)

The viewing mode the image presentation component is transitioning from.

[`let targetViewingMode: ImagePresentationComponent.ViewingMode`](/documentation/RealityKit/ImagePresentationEvents/TransitionStarted/targetViewingMode)

The viewing mode the image presentation component is transitioning to.

## Relationships

### Conforms To

[`SendableMetatype`](/documentation/Swift/SendableMetatype)

[`Sendable`](/documentation/Swift/Sendable)

[`Event`](/documentation/RealityKit/Event)

---

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