---
title: momentumPhase
framework: appkit
role: symbol
role_heading: Instance Property
path: appkit/nsevent/momentumphase
---

# momentumPhase

The momentum phase for a scroll or flick gesture.

## Declaration

```swift
var momentumPhase: NSEvent.Phase { get }
```

## Discussion

Discussion This property is valid for NSScrollWheel events. With the Magic Mouse and some trackpads, the user can use a scroll wheel or flick gesture resulting in a stream of scroll events that dissipate over time. The location of these scroll wheel events changes as the user moves the cursor. These events are attached to the view that is under the cursor when the flick occurs. A custom view can use this method to recognize these momentum scroll events and further route the event to the appropriate sub component. See NSEvent.Phase for possible values.

## See Also

### Getting scroll wheel and flick events

- [deltaX](appkit/nsevent/deltax.md)
- [deltaY](appkit/nsevent/deltay.md)
- [deltaZ](appkit/nsevent/deltaz.md)
- [hasPreciseScrollingDeltas](appkit/nsevent/hasprecisescrollingdeltas.md)
- [scrollingDeltaX](appkit/nsevent/scrollingdeltax.md)
- [scrollingDeltaY](appkit/nsevent/scrollingdeltay.md)
- [isDirectionInvertedFromDevice](appkit/nsevent/isdirectioninvertedfromdevice.md)