Files
openlayers/src/ol/tile.js
2016-08-08 09:58:10 -06:00

116 lines
2.2 KiB
JavaScript

goog.provide('ol.Tile');
goog.provide('ol.TileState');
goog.require('ol.events.EventTarget');
goog.require('ol.events.EventType');
/**
* @enum {number}
*/
ol.TileState = {
IDLE: 0,
LOADING: 1,
LOADED: 2,
ERROR: 3,
EMPTY: 4,
ABORT: 5
};
/**
* @classdesc
* Base class for tiles.
*
* @constructor
* @extends {ol.events.EventTarget}
* @param {ol.TileCoord} tileCoord Tile coordinate.
* @param {ol.TileState} state State.
*/
ol.Tile = function(tileCoord, state) {
ol.events.EventTarget.call(this);
/**
* @type {ol.TileCoord}
*/
this.tileCoord = tileCoord;
/**
* @protected
* @type {ol.TileState}
*/
this.state = state;
/**
* An "interim" tile for this tile. The interim tile may be used while this
* one is loading, for "smooth" transitions when changing params/dimensions
* on the source.
* @type {ol.Tile}
*/
this.interimTile = null;
/**
* A key assigned to the tile. This is used by the tile source to determine
* if this tile can effectively be used, or if a new tile should be created
* and this one be used as an interim tile for this new tile.
* @type {string}
*/
this.key = '';
};
ol.inherits(ol.Tile, ol.events.EventTarget);
/**
* @protected
*/
ol.Tile.prototype.changed = function() {
this.dispatchEvent(ol.events.EventType.CHANGE);
};
/**
* Get the HTML image element for this tile (may be a Canvas, Image, or Video).
* @abstract
* @param {Object=} opt_context Object.
* @return {HTMLCanvasElement|HTMLImageElement|HTMLVideoElement} Image.
*/
ol.Tile.prototype.getImage = function(opt_context) {};
/**
* @return {string} Key.
*/
ol.Tile.prototype.getKey = function() {
return this.key + '/' + this.tileCoord;
};
/**
* Get the tile coordinate for this tile.
* @return {ol.TileCoord} The tile coordinate.
* @api
*/
ol.Tile.prototype.getTileCoord = function() {
return this.tileCoord;
};
/**
* @return {ol.TileState} State.
*/
ol.Tile.prototype.getState = function() {
return this.state;
};
/**
* Load the image or retry if loading previously failed.
* Loading is taken care of by the tile queue, and calling this method is
* only needed for preloading or for reloading in case of an error.
* @abstract
* @api
*/
ol.Tile.prototype.load = function() {};