Class: tileLayer

  (2i, 2j),     (2i, 2j + 1)
  (2i + 1, 2j), (2i + 1, 2j + 1)

Extends

• geo.featureLayer

Type Definitions

geo.tileLayer.specgeo.layer.spec

Object specification for a tile layer.

Properties:

Name	Type	Argument	Default	Description
minLevel	number	<optional>	0	The minimum zoom level available.
maxLevel	number	<optional>	18	The maximum zoom level available.
tileOverlap	object	<optional>		Pixel overlap between tiles. Properties Name Type Argument Description x number <optional> Horizontal overlap. y number <optional> Vertical overlap.
tileWidth	number	<optional>	256	The tile width without overlap.
tileHeight	number	<optional>	256	The tile height without overlap.
tilesAtZoom	function	<optional>	null	A function that is given a zoom level and returns {x: (num), y: (num)} with the number of tiles at that zoom level.
cacheSize	number	<optional>	600	The maximum number of tiles to cache. The default is 200 if keepLower is false.
queue	geo.fetchQueue	<optional>		A fetch queue to use. If unspecified, a new queue is created.
queueSize	number	<optional>	6	The queue size. Most browsers make at most 6 requests to any domain, so this should be no more than 6 times the number of subdomains used.
initialQueueSize	number	<optional>	0	The initial queue size. 0 to use the queue size. When querying a tile server that needs to load information before serving the first tile, having an initial queue size of 1 can reduce the load on the tile server. After the initial queue of tiles are loaded, the queueSize is used for all additional queries unless the initialQueueSize is set again or the tile cache is reset.
keepLower	boolean	<optional>	true	When truthy, keep lower zoom level tiles when showing high zoom level tiles. This uses more memory but results in smoother transitions.
wrapX	boolean	<optional>	true	Wrap in the x-direction.
wrapY	boolean	<optional>	false	Wrap in the y-direction.
url	string | function	<optional>	null	A function taking the current tile indices (x, y, level, subdomains) and returning a URL or jquery ajax config to be passed to the {geo.tile} constructor. Example: (x, y, z, subdomains) => "http://example.com/z/y/x.png" If this is a string, a template url with {x}, {y}, {z}, and {s} as template variables. {s} picks one of the subdomains parameter and may contain a comma-separated list of subdomains.
subdomains	string | Array.<string>	<optional>	"abc"	Subdomains to use in template url strings. If a string, this is converted to a list before being passed to a url function.
baseUrl	string	<optional>	null	If defined, use the old-style base url instead of the url parameter. This is functionally the same as using a url of baseUrl/{z}/{x}/{y}.(imageFormat || png). If the specified string does not end in a slash, one is added.
imageFormat	string	<optional>	'png'	This is only used if a baseUrl is specified, in which case it determines the image name extension used in the url.
animationDuration	number	<optional>	0	The number of milliseconds for the tile loading animation to occur. Only some renderers support this.
attribution	string	<optional>		An attribution to display with the layer (accepts HTML).
tileRounding	function	<optional>	Math.round	This function determines which tiles will be loaded when the map is at a non-integer zoom. For example, Math.floor, will use tile level 2 when the map is at zoom 2.9.
tileOffset	function	<optional>		This function takes a zoom level argument and returns, in units of pixels, the coordinates of the point (0, 0) at the given zoom level relative to the bottom left corner of the domain.
tilesMaxBounds	function	<optional>	null	This function takes a zoom level argument and returns an object with x and y in pixels which is used to crop the last row and column of tiles. Note that if tiles wrap, only complete tiles in the wrapping direction(s) are supported, and this max bounds will probably not behave properly.
topDown	boolean	<optional>	false	True if the gcs is top-down, false if bottom-up (the ingcs does not matter, only the gcs coordinate system). When falsy, this inverts the gcs y-coordinate when calculating local coordinates.
idleAfter	string	<optional>	'view'	Consider the layer as idle once a specific set of tiles is loaded. 'view' is when all tiles in view are loaded. 'all' is when tiles in view and tiles that were once requested have been loaded (this corresponds to having all network activity finished).
baseQuad	object	<optional>		A quad feature element to draw before below any tile layers. If specified, this uses the quad defaults, so this is a geo.quadFeature.position object with, typically, an image property added to it. The quad positions are in the map gcs coordinates.
nearestPixel	boolean | number	<optional>		If true, image quads are rendered with near-neighbor sampling. If false, with interpolated sampling. If a number, interpolate at that zoom level or below and nearest neighbor at that zoom level or above.
id	number	<optional>		The id of the layer. Defaults to a increasing sequence.
map	geo.map	<optional>	null	Parent map of the layer.
renderer	string | geo.renderer	<optional>		Renderer to associate with the layer. If not specified, either annotations or features can be used to determine the renderer. If a geo.renderer instance, the renderer is not recreated; not all renderers can be shared by multiple layers.
autoshareRenderer	boolean | string	<optional>	true	If truthy and the renderer supports it, auto-share renderers between layers. Currently, auto-sharing can only occur for webgl renderers and adjacent layers. If true, sharing will only occur if the layers have the same opacity and it is 1 or 0 and any tile layers are below non-tile layers. If "more", sharing will occur for any adjacent layers that have the same opacity. Shared renderers has slightly different behavior than non-shared renderers: changing z-index may result in rerendering and be slightly slower; only one DOM canvas is used for all shared renderers. Some features have slight z-stacking differences in shared versus non-shared renderers.
canvas	HTMLElement	<optional>		If specified, use this canvas rather than a canvas associaied with the renderer directly. Renderers may not support sharing a canvas.
annotations	Array.<string> | object	<optional>		A list of annotations that will be used on this layer, used to select a renderer. Instead of a list, if this is an object, the keys are the annotation names, and the values are each a list of modes that will be used with that annotation. See featuresForAnnotations more details. This is ignored if renderer is specified.
features	Array.<string>	<optional>		A list of features that will be used on this layer, used to select a renderer. Features are the basic feature names (e.g., 'quad'), or the feature name followed by a required capability (e.g., 'quad.image'). This is ignored if renderer or annotations is specified.
active	boolean	<optional>	true	Truthy if the layer has the active css class and may receive native mouse events.
opacity	number	<optional>	1	The layer opacity on a scale of [0-1].
name	string	<optional>	''	A name for the layer for user convenience. If specified, this is also the id property of the containing DOM element.
selectionAPI	boolean	<optional>	true	Truthy if the layer can generate selection and other interaction events.
sticky	boolean	<optional>	true	Truthy if the layer should navigate with the map.
visible	boolean	<optional>	true	Truthy if the layer is visible.
zIndex	number	<optional>		The z-index to assign to the layer (defaults to the index of the layer inside the map).

Static Members

staticgeo.tileLayer.baseQuad

Get/set the baseQuad.

Properties:

Name	Type	Argument	Description
baseQuad	object	<optional>	A quad feature element to draw below any tile layers. If specified, this uses the quad defaults, so this is a geo.quadFeature.position object with, typically, an image property added to it. The quad positions are in the map gcs coordinates.

staticgeo.tileLayer.defaults

This object contains the default options used to initialize the tileLayer.

Members

activeTiles

Readonly accessor to the active tile mapping. This is an object containing all currently drawn tiles (hash(tile) => tile).

Properties:

Name	Type	Description
activeTiles	object	The keys are hash(tile) and the values are tiles.

cache

Readonly accessor to the tile cache object.

Properties:

Name	Type	Description
cache	geo.tileCache	The tile cache object.

inherited idle

Getter for the idle state. Read only.

Properties:

Name	Type	Description
idle	boolean	true if the object is idle (onIdle would call a handler immediately).

inherited protectednewLayerId

Gets a new id number for a layer.

options

Readonly accessor to the options object.

Properties:

Name	Type	Description
options	object	A copy of the options object.

queue

Get/set the queue object.

Properties:

Name	Type	Description
queue	geo.fetchQueue	The current queue.

queueSize

Get/set the queue size.

Properties:

Name	Type	Description
size	number	The queue size.

queueSize

Get/set the initial queue size.

Properties:

Name	Type	Description
size	number	The initial queue size. 0 to use the queue size.

reference

Get/set the tile reference value.

Properties:

Name	Type	Description
reference	string	A reference value to distinguish tiles on this layer.

Methods

inherited active(arg){boolean|this}

layer.js, line 280

Get/Set whether or not the layer is active. An active layer will receive native mouse when the layer is on top. Non-active layers will never receive native mouse events.

Name	Type	Description
arg	boolean	optional If specified, the new active value.

Returns:

Type	Description
boolean | this

inherited addChild(child){this}

sceneObject.js, line 79

Add a child (or an array of children) to the object.

Name	Type	Description
child	geo.object | Array.<geo.object>	A child object or array of child objects.

Returns:

Type	Description
this

inherited addFeature(feature){this}

featureLayer.js, line 60

Add a feature to the layer if it is not already present.

Name	Type	Description
feature	object	the feature to add.

Returns:

Type	Description
this

inherited addPromise(promise){this}

sceneObject.js, line 35

Add the promise here and also propagate up the scene tree.

Name	Type	Description
promise	Promise	A promise object.

Returns:

Type	Description
this

inherited attribution(arg){string|this}

layer.js, line 458

Get or set the attribution html content that will displayed with the layer. By default, nothing will be displayed. Note, this content is not html escaped, so care should be taken when rendering user provided content.

Name	Type	Description
arg	string	nullable An html fragment

Returns:

Type	Description
string | this	Chainable as a setter

inherited autoshareRenderer(){boolean|string}

layer.js, line 145

Get the setting of autoshareRenderer.

Returns:

Type	Description
boolean | string

inherited canvas(){HTMLCanvasElement}

layer.js, line 372

Get canvas of the layer.

Returns:

Type	Description
HTMLCanvasElement	The canvas element associated with the layer.

inherited children(){Array.<geo.object>}

sceneObject.js, line 110

Get an array of the child objects.

Returns:

Type	Description
Array.<geo.object>	A copy of the array of child objects.

clear(){Array.<geo.tile>}

tileLayer.js, line 1122

Remove all active tiles from the canvas.

Returns:

Type	Description
Array.<geo.tile>	The array of tiles removed.

inherited createFeature(featureName, arg){geo.feature}

featureLayer.js, line 42

Create a feature by name.

Name	Type	Description
featureName	string	The name of the feature to create.
arg	object	Properties for the new feature.

Returns:

Type	Description
geo.feature	The created feature.

inherited dataTime(){geo.timestamp}

layer.js, line 397

Return last time data got changed.

Returns:

Type	Description
geo.timestamp	The data time.

inherited deleteFeature(feature){this}

featureLayer.js, line 96

Delete feature.

Name	Type	Description
feature	geo.feature	The feature to delete.

Returns:

Type	Description
this

displayToLevel(pt, zoom){object}

tileLayer.js, line 1580

Convert display pixel coordinates (where (0,0) is the upper left) to layer pixel coordinates (typically (0,0) is the center of the map and the upper-left has the most negative values). By default, this is done at the current base zoom level.

Name	Type	Description
pt	object	optional The point to convert with x and y. If undefined, use the center of the display.
zoom	number	optional If specified, the zoom level to use.

Returns:

Type	Description
object	The point in level coordinates with x and y.

inherited draw(){this}

featureLayer.js, line 264

Draw. If the layer is visible, call the parent class's draw function and the renderer's render function.

Returns:

Type	Description
this

drawTile(tile)

tileLayer.js, line 936

Draw the given tile on the active canvas .

Name	Type	Description
tile	geo.tile	The tile to draw.

inherited features(val){Array.<geo.feature>|this}

featureLayer.js, line 118

Get/Set drawables.

Name	Type	Description
val	Array.<geo.feature>	optional A list of features, or unspecified to return the current feature list. If a list is provided, features are added or removed as needed.

Returns:

Type	Description
Array.<geo.feature> | this	The current features associated with the layer or the current layer.

fromLevel(coord, level){object}

tileLayer.js, line 903

Convert a coordinate from pixel coordinates at the given zoom level to world coordinates.

Name	Type	Description
coord	object	Name Type Description x number The offset in pixels (level 0) from the left edge. y number The offset in pixels (level 0) from the bottom edge.
level	number	The zoom level of the source coordinates.

Returns:

Type	Description
object	World coordinates with x and y.

fromLocal(pt, zoom){object}

tileLayer.js, line 1179

Compute world coordinates from the given local coordinates. The tile layer uses units of pixels relative to the world space coordinate origin.

Name	Type	Description
pt	object	A point in world space coordinates with x and y.
zoom	number | undefined	If unspecified, use the map zoom.

Returns:

Type	Description
object	Local coordinates with x and y.

gcs(arg){string|this}

tileLayer.js, line 811

Get or set the layer gcs. This defaults to the map's gcs.

Name	Type	Description
arg	string	optional If undefined, return the current gcs. Otherwise, a new value for the gcs. If null, use the map's gcs.

Returns:

Type	Description
string | this	A string used by geo.transform.

inherited gcsFeatures(val){string|this}

featureLayer.js, line 151

Get or set the gcs for all features. For features, the default is usually the map's ingcs.

Name	Type	Description
val	string	optional nullable If undefined, return the current gcs. If null, use the map's interface gcs. Otherwise, set a new value for the gcs. When getting the current gcs, if not all features have the same gcs, undefined will be returned.

Returns:

Type	Description
string | this	A string used by geo.transform. If the map interface gcs is in use, that value will be returned. If the gcs is set, return the current class instance.

gcsTileBounds(indexOrTile, gcs){object}

tileLayer.js, line 552

Returns a tile's bounds in a gcs.

Name	Type	Description
indexOrTile	object | geo.tile	Either a tile or an object with {x, y, level}` specifying a tile.
gcs	string | geo.transform | null	optional undefined to use the interface gcs, null to use the map gcs, or any other transform.

Returns:

Type	Description
object	The tile bounds in the specified gcs.

inherited geoIsOn(event, handler){boolean}

object.js, line 187

Report if an event handler is bound to this object.

Name	Type	Description
event	string | Array.<string>	An event or list of events to check.
handler	function	optional A function that might be bound. If undefined, this will report true if there is any handler for the specified event.

Returns:

Type	Description
boolean	true if any of the specified events are bound to the specified handler.

inherited geoOff(event, arg){this}

object.js, line 246

Remove handlers from one event or an array of events. If no event is provided all handlers will be removed.

Name	Type	Description
event	string | Array.<string>	optional An event or a list of events from geo.event or defined by the user, or undefined to remove all events (in which case arg is ignored).
arg	function | Array.<function()>	optional nullable A function or array of functions to remove from the events or a falsy value to remove all handlers from the events.

Returns:

Type	Description
this

inherited geoOn(event, handler){this}

object.js, line 139

Bind an event handler to this object.

Name	Type	Description
event	string	An event from geo.event or a user-defined value.
handler	function	A function that is called when event is triggered. The function is passed a geo.event object.

Returns:

Type	Description
this

inherited geoOnce(event, handler){function}

object.js, line 168

Bind an event handler to this object that will fire once and then deregister itself.

Name	Type	Description
event	string	An event from geo.event or a user-defined value.
handler	function	A function that is called when event is triggered. The function is passed a geo.event object.

Returns:

Type	Description
function	The actual bound handler. This is a wrapper around the handler that was passed to the function.

inherited geoTrigger(event, args, childrenOnly){this}

sceneObject.js, line 136

Trigger an event (or events) on this object and call all handlers.

Name	Type	Description
event	string	The event to trigger.
args	object	Arbitrary argument to pass to the handler.
childrenOnly	boolean	optional If truthy, only propagate down the tree.

Returns:

Type	Description
this

inherited height(){number}

layer.js, line 604

Return the height of the layer in pixels.

Returns:

Type	Description
number	The height of the parent map in pixels.

inherited id(val){string|this}

layer.js, line 307

Get/Set id of the layer.

Name	Type	Description
val	string | null	optional If null, generate a new layer id. Otherwise, if specified, the new id of the layer.

Returns:

Type	Description
string | this

inherited initialized(val){boolean|this}

layer.js, line 417

Get/Set if the layer has been initialized.

Name	Type	Description
val	boolean	optional If specified, update the initialized value. Otherwise, return the current instance.

Returns:

Type	Description
boolean | this	Either the initialized value or this.

isValid(index){boolean}

tileLayer.js, line 451

Returns true if the given tile index is valid:

• min level <= level <= max level
• 0 <= x <= 2^level - 1
• 0 <= y <= 2^level - 1 If the layer wraps, the x and y values may be allowed to extend beyond these values.

Name	Type	Description
index	object	The tile index. Name Type Description x number y number level number

Returns:

Type	Description
boolean

inherited map(){geo.map}

layer.js, line 337

Get the map associated with this layer.

Returns:

Type	Description
geo.map	The map associated with the layer.

inherited modified(){this}

timestamp.js, line 25

Update the timestamp to the next global timestamp value.

Returns:

Type	Description
this

inherited moveDown(n){this}

layer.js, line 238

Bring the layer below the given number of layers. This will rotate the current z-indices for this and the previous n layers.

Name	Type	Default	Description
n	number	1	optional The number of positions to move.

Returns:

Type	Description
this

inherited moveToBottom(){this}

layer.js, line 259

Bring the layer to the bottom of the map layers.

Returns:

Type	Description
this

inherited moveToTop(){this}

layer.js, line 250

Bring the layer to the top of the map layers.

Returns:

Type	Description
this

inherited moveUp(n){this}

layer.js, line 191

Bring the layer above the given number of layers. This will rotate the current z-indices for this and the next n layers.

Name	Type	Default	Description
n	number	1	optional The number of positions to move.

Returns:

Type	Description
this

inherited name(val){string|this}

layer.js, line 322

Get/Set name of the layer.

Name	Type	Description
val	string	optional If specified, the new name of the layer.

Returns:

Type	Description
string | this

nearestPixel(val, skipUpdate){boolean|number|this}

tileLayer.js, line 1701

Get/Set nearestPixel value.

Name	Type	Description
val	boolean | number	optional If not specified, return the current value. If true, image quads are rendered with near-neighbor sampling. If false, with interpolated sampling. If a number, interpolate at that zoom level or below and nearest neighbor at that zoom level or above.
skipUpdate	boolean	optional If specifying val and this value is truthy, don't update the layer or mark it as modified.

Returns:

Type	Description
boolean | number | this

inherited node(){HTMLDivElement}

layer.js, line 296

Get root node of the layer.

Returns:

Type	Description
HTMLDivElement

inherited onIdle(handler){this}

object.js, line 36

Bind a handler that will be called one time when all internal promises are resolved. If there are no outstanding promises, this is invoked synchronously.

Name	Type	Description
handler	function	A function taking no arguments.

Returns:

Type	Description
this

inherited opacity(opacity){number|this}

layer.js, line 617

Get or set the current layer opacity. The opacity is in the range [0-1]. An opacity of 0 is not the same as setting visible(false), as interactions can still occur with the layer.

Name	Type	Description
opacity	number	optional If specified, set the opacity. Otherwise, return the opacity.

Returns:

Type	Description
number | this	The current opacity or the current layer.

inherited parent(arg){this|geo.sceneObject}

sceneObject.js, line 64

Get/set parent of the object.

Name	Type	Description
arg	geo.sceneObject	optional The new parant or undefined to get the current parent.

Returns:

Type	Description
this | geo.sceneObject

prefetch(level, bounds){jQuery.Deferred}

tileLayer.js, line 837

Prefetches tiles up to a given zoom level around a given bounding box.

Name	Type	Description
level	number	The zoom level.
bounds	geo.geoBounds	The map bounds.

Returns:

Type	Description
jQuery.Deferred	resolves when all of the tiles are fetched.

remove(tile){geo.tile}

tileLayer.js, line 1012

Remove the given tile from the canvas and the active cache.

Name	Type	Description
tile	geo.tile | string	The tile (or hash) to remove.

Returns:

Type	Description
geo.tile	The tile removed from the active layer.

inherited removeChild(child){this}

sceneObject.js, line 96

Remove a child (or array of children) from the object.

Name	Type	Description
child	geo.object | Array.<geo.object>	A child object or array of child objects.

Returns:

Type	Description
this

inherited removeFeature(feature){this}

featureLayer.js, line 76

Remove a feature without destroying it.

Name	Type	Description
feature	geo.feature	The feature to remove.

Returns:

Type	Description
this

inherited removePromise(promise){this}

sceneObject.js, line 49

Remove the promise here and also propagate up the scene tree.

Name	Type	Description
promise	Promise	A promise object.

Returns:

Type	Description
this

inherited renderer(){geo.renderer}

layer.js, line 347

Get the renderer for the layer.

Returns:

Type	Description
geo.renderer	The renderer associated with the layer or null if there is no renderer.

inherited rendererName(){string}

layer.js, line 136

Get the name of the renderer.

Returns:

Type	Description
string

reset(){this}

tileLayer.js, line 1145

Reset the layer to the initial state, clearing the canvas and resetting the tile cache.

Returns:

Type	Description
this

inherited selectionAPI(val){boolean|this}

featureLayer.js, line 312

Get/Set selectionAPI of the layer.

Name	Type	Description
val	boolean	optional If specified change the selectionAPI state of the layer, otherwise return the current state.

Returns:

Type	Description
boolean | this	The selectionAPI state or the current layer.

inherited sticky(){boolean}

layer.js, line 268

Get whether or not the layer is sticky (navigates with the map).

Returns:

Type	Description
boolean

subdomains(subdomains){string|Array.<string>|this}

tileLayer.js, line 1635

Get or set the subdomains used for templating.

Name	Type	Description
subdomains	string | Array.<string>	optional A comma-separated list, a string of single character subdomains, or a list.

Returns:

Type	Description
string | Array.<string> | this

tileAtPoint(point, level){object}

tileLayer.js, line 521

Returns the tile indices at the given point.

Name	Type	Description
point	object	The coordinates in pixels relative to the map origin. Name Type Description x number y number
level	number	The target zoom level.

Returns:

Type	Description
object	The tile indices. This has x and y properties.

tileCropFromBounds(tile){object}

tileLayer.js, line 419

Get the crop values for a tile based on the tilesMaxBounds function. Returns undefined if the tile should not be cropped.

Name	Type	Description
tile	object	The tile to compute crop values for.

Returns:

Type	Description
object	Either undefined or an object with x and y values which is the size in pixels for the tile.

tilesAtZoom(level){object}

tileLayer.js, line 388

The number of tiles at the given zoom level. The default implementation just returns Math.pow(2, z).

Name	Type	Description
level	number	A zoom level.

Returns:

Type	Description
object	The number of tiles in each axis in the form {x: nx, y: ny}.

tilesMaxBounds(level){object}

tileLayer.js, line 404

The maximum tile bounds at the given zoom level, or null if no special tile bounds.

Name	Type	Description
level	number	A zoom level.

Returns:

Type	Description
object	The maximum tile bounds in pixels for the specified level, or null if none specified ({x: width, y: height}).

inherited timestamp(){number}

timestamp.js, line 37

Get time.

Returns:

Type	Description
number	The timestamp. This is 0 if the timestamp has never been modified.

toLevel(coord, level){object}

tileLayer.js, line 923

Convert a coordinate from layer coordinates to pixel coordinates at the given zoom level.

Name	Type	Description
coord	object	Name Type Description x number The offset in pixels (level 0) from the left edge. y number The offset in pixels (level 0) from the bottom edge.
level	number	The zoom level of the new coordinates.

Returns:

Type	Description
object	The pixel coordinates with x and y.

toLocal(pt, zoom){object}

tileLayer.js, line 1161

Compute local coordinates from the given world coordinates. The tile layer uses units of pixels relative to the world space coordinate origin.

Name	Type	Description
pt	object	A point in world space coordinates with x and y.
zoom	number	optional If unspecified, use the map zoom.

Returns:

Type	Description
object	Local coordinates with x and y.

inherited updateTime(){geo.timestamp}

layer.js, line 406

Return the modified time for the last update that did something.

Returns:

Type	Description
geo.timestamp	The update time.

url(url){string|function|this}

tileLayer.js, line 1611

Get or set the tile url string or function. If changed, load the new tiles.

Name	Type	Description
url	string | function	optional The new tile url.

Returns:

Type	Description
string | function | this

visible(val){boolean|this}

tileLayer.js, line 1676

Get/Set visibility of the layer.

Name	Type	Description
val	boolean	optional If unspecified, return the visibility, otherwise set it.

Returns:

Type	Description
boolean | this	Either the visibility (if getting) or the layer (if setting).

inherited width(){number}

layer.js, line 595

Return the width of the layer in pixels.

Returns:

Type	Description
number	The width of the parent map in pixels.

inherited zIndex(zIndex, allowDuplicate){number|this}

layer.js, line 160

Get or set the z-index of the layer. The z-index controls the display order of the layers in much the same way as the CSS z-index property.

Name	Type	Description
zIndex	number	optional The new z-index, or undefined to return the current z-index.
allowDuplicate	boolean	optional When setting the z index, if this is truthy, allow other layers to have the same z-index. Otherwise, ensure that other layers have distinct z-indices from this one.

Returns:

Type	Description
number | this