MotionState

public struct MotionState<RootClass, PropertyType>

This struct represents the states of a single object to be used in a motion operation, used to create PropertyData objects for each object property. Because the start and end properties can represent any value type, it is used by ValueAssistant classes to internally generate PropertyData objects for each property value of the object. As such, it is a convenient way to set up many property value interpolations for an object by simply passing in representations of that object at its starting and ending points.

Note

These state values must be of the same object type as the property located at the keyPath. For instance, if the keyPath property points to a CGRect object, you must provide CGRect objects for the start and end properties.

  • An optional starting state for the motion operation, used to generate PropertyData objects for each object property. If no value is supplied, the existing object’s state will be used.

    Note

    Depending on the state object being used for property generation, multiple PropertyData objects may result, such as the x and y properties of CGPoint. ValueAssistant classes make a best attempt at ignoring the generation of properties whose values do not change between the starting and ending states.

    Declaration

    Swift

    public var start: PropertyType?
  • end

    An ending state for the motion operation, used to generate PropertyData objects for each object property. If no value is supplied, the existing object’s state will be used.

    Note

    Depending on the state object being used for property generation, multiple PropertyData objects may result, such as the x and y properties of CGPoint. ValueAssistant classes make a best attempt at ignoring the generation of properties whose values do not change between the starting and ending states.

    Declaration

    Swift

    public let end: PropertyType

  • A KeyPath object representing the object to be transformed.

    Declaration

    Swift

    public let keyPath: AnyKeyPath

  • The initializer.

    Declaration

    Swift

    public init(keyPath: KeyPath<RootClass, PropertyType>, start: PropertyType? = nil, end: PropertyType)

    Parameters

    keyPath

    A KeyPath which points to an object of the same type as the provided states.
    start

    A state representing the starting property values of the motion operation.
    end

    A stte representing the ending property values of the motion operation.

  • Retrieves a value from the provided object using the keyPath property.

    Declaration

    Swift

    public func retrieveValue(from target: RootClass) -> (Any)?

    Parameters

    target

    The target object to retrieve a value from.

    Return Value

    The result of the keypath retrieval, if one was found.