danielctull-forks / cascablecore-swift

A Swift-y API for CascableCore.

CascableCoreSwift

CascableCoreSwift is a Swift package that provides a better, more "Swift-y" API for CascableCore.

This package is currently in very early alpha, and depends on an alpha version of CascableCore.

Strongly-Typed Property API

This package adds a strongly-typed property API to Camera, allowing much nicer property-manipulating code to be written in Swift. The API is largely similar to the new Objective-C version introduced in CascableCore 10.0, except for the following:

• Key-Value Observing cannot be used.

• There is no special "exposure" property type, and no currentExposureValue property. Instead, such properties are simply strongly-typed with an exposure type, and commonValue returns the exposure value.

• commonValue can now return nil (instead of PropertyCommonValueNone).

For example:

let isoProperty = camera.property(for: .iso) // Gives you a `TypedCameraProperty<ISOValue>`
print("ISO is: \(isoProperty.currentValue.localizedDisplayValue)")

// Because properties are strongly-typed, we can do nice logic.
if isoProperty?.commonValue == .iso100 { print("ISO 100!") }

// Important: The observation will invalidate when this token is 
// deallocated — it should be stored somewhere!
let observerToken = property.addObserver { property, changeType in
    if changeType.contains(.value) { 
       print("ISO changed to: \(property.currentValue.localizedDisplayValue)!")
    }
    
    if changeType.contains(.validSettableValues) {
        print("Valid ISOs changed to: \(property.validSettableValues.compactMap({ $0.localizedDisplayValue }))!")
    }
}

For documentation on the new property API introduced with CascableCore 10.0, see the documentation in CascableCore.

Combine Publishers

If you're a fan of Combine, this package provides a combine publisher for property values.

Basic Usage

There are two APIs added to Camera, which are convenience methods for creating publishers for camera values or valid settable values. For example:

camera.valuePublisher(for: .shutterSpeed).sink { shutterSpeed in 
    print("The current shutter speed is: \(shutterSpeed?.localizedDisplayValue ?? "nil")")
}

camera.settableValuesPublisher(for: .shutterSpeed).sink { shutterSpeeds in 
    print("Valid shutter speeds are: \(shutterSpeeds.compactMap({ $0.localizedDisplayValue }))")
}

Also included is a general-purpose helper for "flattening" combined publishers, called .flatten(). For example:

camera.valuePublisher(for: .shutterSpeed)
    .combineLatest(camera.valuePublisher(for: .aperture))
    .combineLatest(camera.valuePublisher(for: .iso))
    .flatten()
    .sink { shutter, aperture, iso in
        print("Exposure triangle values: \(shutter), \(aperture), \(iso)")
    }