OpenLayers.Tile

This is a class designed to designate a single tile, however it is explicitly designed to do relatively little.  Tiles store information about themselves -- such as the URL that they are related to, and their size - but do not add themselves to the layer div automatically, for example.  Create a new tile with the OpenLayers.Tile constructor, or a subclass.

TBD 3.0remove reference to url in above paragraph
Summary
OpenLayers.TileThis is a class designed to designate a single tile, however it is explicitly designed to do relatively little.
Properties
events{OpenLayers.Events} An events object that handles all events on the tile.
eventListeners{Object} If set as an option at construction, the eventListeners object will be registered with OpenLayers.Events.on.
id{String} null
layer{<OpenLayers.Layer>} layer the tile is attached to
url{String} url of the request.
bounds{OpenLayers.Bounds} null
size{OpenLayers.Size} null
position{OpenLayers.Pixel} Top Left pixel of the tile
isLoading{Boolean} Is the tile loading?
Functions
unloadCall immediately before destroying if you are listening to tile events, so that counters are properly handled if tile is still loading at destroy-time.
destroyNullify references to prevent circular references and memory leaks.
drawClear whatever is currently in the tile, then return whether or not it should actually be re-drawn.
shouldDrawReturn whether or not the tile should actually be (re-)drawn.
setBoundsSets the bounds on this instance
moveToReposition the tile.
clearClear the tile of any bounds/position-related data so that it can be reused in a new location.

Properties

events

{OpenLayers.Events} An events object that handles all events on the tile.

eventListeners

{Object} If set as an option at construction, the eventListeners object will be registered with OpenLayers.Events.on.  Object structure must be a listeners object as shown in the example for the events.on method.

This options can be set in the ``tileOptions`` option from OpenLayers.Layer.Grid.  For example, to be notified of the ``loadend`` event of each tiles:

new OpenLayers.Layer.OSM('osm', 'http://tile.openstreetmap.org/${z}/${x}/${y}.png', {
    tileOptions: {
        eventListeners: {
            'loadend': function(evt) {
                // do something on loadend
            }
        }
    }
});

id

{String} null

layer

{<OpenLayers.Layer>} layer the tile is attached to

url

{String} url of the request.

TBD 3.0 Deprecated.  The base tile class does not need an url.  This should be handled in subclasses.  Does not belong here.

bounds

size

position

{OpenLayers.Pixel} Top Left pixel of the tile

isLoading

{Boolean} Is the tile loading?

Functions

unload

unload: function()

Call immediately before destroying if you are listening to tile events, so that counters are properly handled if tile is still loading at destroy-time.  Will only fire an event if the tile is still loading.

destroy

destroy:function()

Nullify references to prevent circular references and memory leaks.

draw

draw: function()

Clear whatever is currently in the tile, then return whether or not it should actually be re-drawn.  This is an example implementation that can be overridden by subclasses.  The minimum thing to do here is to call clear and return the result from shouldDraw.

Returns

{Boolean} Whether or not the tile should actually be drawn.

shouldDraw

shouldDraw: function()

Return whether or not the tile should actually be (re-)drawn.  The only case where we wouldn’t want to draw the tile is if the tile is outside its layer’s maxExtent

Returns

{Boolean} Whether or not the tile should actually be drawn.

setBounds

setBounds: function(bounds)

Sets the bounds on this instance

Parameters

bounds {OpenLayers.Bounds}

moveTo

moveTo: function (bounds,
position,
redraw)

Reposition the tile.

Parameters

bounds{OpenLayers.Bounds}
position{OpenLayers.Pixel}
redraw{Boolean} Call draw method on tile after moving.  Default is true

clear

clear: function(draw)

Clear the tile of any bounds/position-related data so that it can be reused in a new location.  To be implemented by subclasses.

on: function(object)
Convenience method for registering listeners with a common scope.
Instances of this class represent bounding boxes.
Instances of this class represent a width/height pair
This class represents a screen coordinate, in x and y coordinates
unload: function()
Call immediately before destroying if you are listening to tile events, so that counters are properly handled if tile is still loading at destroy-time.
destroy:function()
Nullify references to prevent circular references and memory leaks.
draw: function()
Clear whatever is currently in the tile, then return whether or not it should actually be re-drawn.
shouldDraw: function()
Return whether or not the tile should actually be (re-)drawn.
setBounds: function(bounds)
Sets the bounds on this instance
moveTo: function (bounds,
position,
redraw)
Reposition the tile.
clear: function(draw)
Clear the tile of any bounds/position-related data so that it can be reused in a new location.
This is a class designed to designate a single tile, however it is explicitly designed to do relatively little.
Base class for layers that use a lattice of tiles.
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