---
title: NSLayoutConstraint.Axis
framework: uikit
role: symbol
role_heading: Enumeration
path: uikit/nslayoutconstraint/axis
---

# NSLayoutConstraint.Axis

Keys that specify a horizontal or vertical layout constraint between objects.

## Declaration

```swift
enum Axis
```

## Topics

### Constants

- [NSLayoutConstraint.Axis.horizontal](uikit/nslayoutconstraint/axis/horizontal.md)
- [NSLayoutConstraint.Axis.vertical](uikit/nslayoutconstraint/axis/vertical.md)

### Initializers

- [init(rawValue:)](uikit/nslayoutconstraint/axis/init(rawvalue:).md)

## Relationships

### Conforms To

- [BitwiseCopyable](swift/bitwisecopyable.md)
- [Equatable](swift/equatable.md)
- [Hashable](swift/hashable.md)
- [RawRepresentable](swift/rawrepresentable.md)
- [Sendable](swift/sendable.md)
- [SendableMetatype](swift/sendablemetatype.md)

## See Also

### Constants

- [NSLayoutConstraint.Relation](uikit/nslayoutconstraint/relation-swift.enum.md)
- [NSLayoutConstraint.Attribute](uikit/nslayoutconstraint/attribute.md)
- [NSLayoutConstraint.FormatOptions](uikit/nslayoutconstraint/formatoptions.md)
- [NSLayoutConstraint.Orientation](appkit/nslayoutconstraint/orientation.md)
- [NSEdgeInsets](foundation/nsedgeinsets.md)
- [NSLAYOUTCONSTRAINT_H](uikit/nslayoutconstraint_h.md)