MGLSourceStyleFunction

 

@interface MGLSourceStyleFunction <T> : MGLStyleFunction<T>

An MGLSourceStyleFunction is a value function defining a style value that changes with its properties. The layout and paint attribute properties of an MGLStyleLayer object can be set to MGLSourceStyleFunction objects. Use source functions to visually differentate types of features within the same layer or create data visualizations.

The MGLSourceStyleFunction class takes a generic parameter T that indicates the Foundation class being wrapped by this class.

Creating a Source Function

  • Creates and returns an MGLSourceStyleFunction object representing a source function.

    Declaration

    Objective-C

    + (nonnull instancetype)
functionWithInterpolationMode:(MGLInterpolationMode)interpolationMode
                        stops:(nullable NSDictionary<id, MGLStyleValue<T> *> *)
                                  stops
                attributeName:(nonnull NSString *)attributeName
                      options:
                          (nullable NSDictionary<MGLStyleFunctionOption, id> *)
                              options;

    Swift

    convenience init(interpolationMode: MGLInterpolationMode, stops: [AnyHashable : MGLStyleValue

    Parameters

    interpolationMode

    The mode used to interpolate property values over a range of feature attribute values.
    stops

    A dictionary associating feature attributes with style values.
    attributeName

    Specifies the feature attribute to take as the function input.
    options

    A dictionary containing MGLStyleFunctionOption values that specify how a function is applied.

    Return Value

    An MGLSourceStyleFunction object with the given interpolation mode, source stops, attribute name, and options.

    View Source on GitHub

Accessing the Parameters of a Source Function

  • A string that specifies the feature attribute key whose value be used as the function input.

    Declaration

    Objective-C

    @property (readwrite, copy, nonatomic) NSString *_Nonnull attributeName;

    Swift

    var attributeName: String { get set }
    View Source on GitHub

  • A dictionary associating attribute values with style values.

    Each of the function’s stops is represented by one key-value pair in the dictionary. Each key in the dictionary is an object representing a feature attribute key or interpolation stop. Each value in the dictionary is an MGLStyleValue object containing the value to use when the function is given the associated attribute key. An MGLStyleFunction object may not be used recursively as a stop value.

    Declaration

    Objective-C

    @property (readwrite, copy, nonatomic, nullable)
    NSDictionary<id, MGLStyleValue<T> *> *stops;

    Swift

    var stops: [AnyHashable : MGLStyleValue
    View Source on GitHub

  • An MGLStyleValue object containing the default value to use when there is no input to provide to the function.

    Declaration

    Objective-C

    @property (assign, readwrite, nonatomic, nullable)
    MGLStyleValue<T> *defaultValue;

    Swift

    var defaultValue: MGLStyleValue
    View Source on GitHub