goog.provide('ol.TilePriorityFunction');
goog.provide('ol.TileQueue');
goog.require('goog.events');
goog.require('goog.events.EventType');
goog.require('ol.Coordinate');
goog.require('ol.TileState');
goog.require('ol.structs.PriorityQueue');
/**
* @typedef {function(ol.Tile, string, ol.Coordinate, number): number}
*/
ol.TilePriorityFunction;
/**
* @constructor
* @extends {ol.structs.PriorityQueue.<Array>}
* @param {ol.TilePriorityFunction} tilePriorityFunction
* Tile priority function.
* @param {function(): ?} tileChangeCallback
* Function called on each tile change event.
* @struct
*/
ol.TileQueue = function(tilePriorityFunction, tileChangeCallback) {
goog.base(
this,
/**
* @param {Array} element Element.
* @return {number} Priority.
*/
function(element) {
return tilePriorityFunction.apply(null, element);
},
/**
* @param {Array} element Element.
* @return {string} Key.
*/
function(element) {
return /** @type {ol.Tile} */ (element[0]).getKey();
});
/**
* @private
* @type {function(): ?}
*/
this.tileChangeCallback_ = tileChangeCallback;
/**
* @private
* @type {number}
*/
this.tilesLoading_ = 0;
};
goog.inherits(ol.TileQueue, ol.structs.PriorityQueue);
/**
* @return {number} Number of tiles loading.
*/
ol.TileQueue.prototype.getTilesLoading = function() {
return this.tilesLoading_;
};
/**
* @param {goog.events.Event} event Event.
* @protected
*/
ol.TileQueue.prototype.handleTileChange = function(event) {
var tile = /** @type {ol.Tile} */ (event.target);
var state = tile.getState();
if (state === ol.TileState.LOADED || state === ol.TileState.ERROR ||
state === ol.TileState.EMPTY) {
goog.events.unlisten(tile, goog.events.EventType.CHANGE,
this.handleTileChange, false, this);
--this.tilesLoading_;
this.tileChangeCallback_();
}
};
/**
* @param {number} maxTotalLoading Maximum number tiles to load simultaneously.
* @param {number} maxNewLoads Maximum number of new tiles to load.
*/
ol.TileQueue.prototype.loadMoreTiles = function(maxTotalLoading, maxNewLoads) {
var newLoads = 0;
var tile;
while (this.tilesLoading_ < maxTotalLoading && newLoads < maxNewLoads &&
this.getCount() > 0) {
tile = /** @type {ol.Tile} */ (this.dequeue()[0]);
if (tile.getState() === ol.TileState.IDLE) {
goog.events.listen(tile, goog.events.EventType.CHANGE,
this.handleTileChange, false, this);
tile.load();
++this.tilesLoading_;
++newLoads;
}
}
};
|