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Vision · IOS API REFERENCE

HorizonObservation

struct · iOS 18.0+ · SDK 27.1

struct HorizonObservation

The horizon angle information that an image analysis request detects. Instances of this class result from invoking a ``DetectHorizonRequest``, and report the angle and transform of the horizon in an image.

Members (9)

get · iOS 18.0+

confidence

TypeScript
get confidence(): number
Swift declaration
let confidence: Float

The level of confidence normalized to `[0, 1]` where `1` is most confident. The only exception is results coming from `CoreMLRequest`, where confidence values are forwarded as is from relevant CoreML models

get · iOS 18.0+

description

TypeScript
get description(): string
Swift declaration
var description: String { get }

A textual representation of this instance. Calling this property directly is discouraged. Instead, convert an instance of any type to a string by using the `String(describing:)` initializer. This initializer works with any type, and uses the custom `description` property for types that conform to `CustomStringConvertible`: struct Point: CustomStringConvertible { let x: Int, y: Int var description: String { return "(\(x), \(y))" } } let p = Point(x: 21, y: 30) let s = String(describing: p) print(s) // Prints "(21, 30)" The conversion of `p` to a string in the assignment to `s` uses the `Point` type's `description` property.

get · iOS 18.0+

originatingRequestDescriptor

TypeScript
get originatingRequestDescriptor(): (RequestDescriptor) | null
Swift declaration
let originatingRequestDescriptor: RequestDescriptor?

The descriptor of the request that produced the observation.

get · iOS 18.0+

uuid

TypeScript
get uuid(): string
Swift declaration
let uuid: UUID

The unique identifier for the observation.

get · iOS 18.0+

angle

TypeScript
get angle(): _Foundation_Measurement<_Foundation_UnitAngle>
Swift declaration
let angle: Measurement<UnitAngle>

The angle of the observed horizon. Use the angle to orient the image in an upright position and make the detected horizon level.

get · iOS 18.0+

timeRange

TypeScript
get timeRange(): (_CoreMedia_CMTimeRange) | null
Swift declaration
let timeRange: CMTimeRange?

The time range of the reported observation. When evaluating a sequence of image buffers, use this property to determine each observation’s start time and duration.

method · iOS 18.0+

transform

TypeScript
transformFor(imageSize: { width: number; height: number }): _CoreFoundation_CGAffineTransform
Swift declaration
func transform(for imageSize: CGSize) -> CGAffineTransform

Creates an affine transform for the specified image width and height. - Parameters: - imageSize: The size of the image. - Returns: An affine transform. Apply the transform's inverse to orient the image in an upright position and make the detected horizon level.

get · iOS 18.0+

transform

TypeScript
get transform(): _CoreFoundation_CGAffineTransform
Swift declaration
let transform: CGAffineTransform

The transform to apply to the detected horizon. Apply the transform's inverse to orient the image in an upright position and make the detected horizon level.

init · iOS 18.0+

init

TypeScript
static init(observation: VNHorizonObservation): HorizonObservation
Swift declaration
init(_ observation: VNHorizonObservation)

Skipped declarations

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