MGLBackgroundStyleLayer

@interface MGLBackgroundStyleLayer : MGLStyleLayer

An MGLBackgroundStyleLayer is a style layer that covers the entire map. Use a background style layer to configure a color or pattern to show below all other map content. If the style’s other layers use the MapTiler Streets source, the background style layer is responsible for drawing land, whereas the oceans and other bodies of water are drawn by MGLFillStyleLayer objects.

A background style layer is typically the bottommost layer in a style, because it covers the entire map and can occlude any layers below it. You can therefore access it by getting the last item in the MGLStyle.layers array.

If the background style layer is transparent or omitted from the style, any portion of the map view that does not show another style layer is transparent.

-initWithIdentifier:

Returns a background style layer initialized with an identifier.

After initializing and configuring the style layer, add it to a map view’s style using the -[MGLStyle addLayer:] or -[MGLStyle insertLayer:belowLayer:] method.

Declaration

Objective-C

- (nonnull instancetype)initWithIdentifier:(nonnull NSString *)identifier;

Swift

init(identifier: String)

Parameters

identifier

A string that uniquely identifies the source in the style to which it is added.

Accessing the Paint Attributes

backgroundColor

The color with which the background will be drawn.

The default value of this property is an expression that evaluates to UIColor.blackColor. Set this property to nil to reset it to the default value.

This property is only applied to the style if backgroundPattern is set to nil. Otherwise, it is ignored.

You can set this property to an expression containing any of the following:

• Constant UIColor values
• Predefined functions, including mathematical and string operators
• Conditional expressions
• Variable assignments and references to assigned variables
• Interpolation and step functions applied to the $zoomLevel variable

This property does not support applying interpolation or step functions to feature attributes.

Declaration

Objective-C

@property (nonatomic, assign, unsafe_unretained, readwrite, null_resettable)
NSExpression *backgroundColor;

Swift

var backgroundColor: NSExpression! { get set }

backgroundColorTransition

The transition affecting any changes to this layer’s backgroundColor property.

This property corresponds to the background-color-transition property in the style JSON file format.

Declaration

Objective-C

@property (nonatomic, assign, unsafe_unretained, readwrite)
MGLTransition backgroundColorTransition;

Swift

var backgroundColorTransition: MGLTransition { get set }

backgroundOpacity

The opacity at which the background will be drawn.

The default value of this property is an expression that evaluates to the float 1. Set this property to nil to reset it to the default value.

You can set this property to an expression containing any of the following:

• Constant numeric values between 0 and 1 inclusive
• Predefined functions, including mathematical and string operators
• Conditional expressions
• Variable assignments and references to assigned variables
• Interpolation and step functions applied to the $zoomLevel variable

This property does not support applying interpolation or step functions to feature attributes.

Declaration

Objective-C

@property (nonatomic, assign, unsafe_unretained, readwrite, null_resettable)
NSExpression *backgroundOpacity;

Swift

var backgroundOpacity: NSExpression! { get set }

backgroundOpacityTransition

The transition affecting any changes to this layer’s backgroundOpacity property.

This property corresponds to the background-opacity-transition property in the style JSON file format.

Declaration

Objective-C

@property (nonatomic, assign, unsafe_unretained, readwrite)
MGLTransition backgroundOpacityTransition;

Swift

var backgroundOpacityTransition: MGLTransition { get set }

backgroundPattern

Name of image in style images to use for drawing an image background. For seamless patterns, image width and height must be a factor of two (2, 4, 8, …, 512).

You can set this property to an expression containing any of the following:

• Constant string values
• Predefined functions, including mathematical and string operators
• Conditional expressions
• Variable assignments and references to assigned variables
• Step functions applied to the $zoomLevel variable

This property does not support applying interpolation functions to the $zoomLevel variable or applying interpolation or step functions to feature attributes.

Declaration

Objective-C

@property (nonatomic, assign, unsafe_unretained, readwrite, null_resettable)
NSExpression *backgroundPattern;

Swift

var backgroundPattern: NSExpression! { get set }

backgroundPatternTransition

The transition affecting any changes to this layer’s backgroundPattern property.

This property corresponds to the background-pattern-transition property in the style JSON file format.

Declaration

Objective-C

@property (nonatomic, assign, unsafe_unretained, readwrite)
MGLTransition backgroundPatternTransition;

Swift

var backgroundPatternTransition: MGLTransition { get set }