Files
openlayers/src/ol/imagetile.js
2016-08-04 11:29:54 +02:00

170 lines
3.6 KiB
JavaScript

goog.provide('ol.ImageTile');
goog.require('ol.Tile');
goog.require('ol.TileState');
goog.require('ol.events');
goog.require('ol.events.EventType');
goog.require('ol.object');
/**
* @constructor
* @extends {ol.Tile}
* @param {ol.TileCoord} tileCoord Tile coordinate.
* @param {ol.TileState} state State.
* @param {string} src Image source URI.
* @param {?string} crossOrigin Cross origin.
* @param {ol.TileLoadFunctionType} tileLoadFunction Tile load function.
*/
ol.ImageTile = function(tileCoord, state, src, crossOrigin, tileLoadFunction) {
ol.Tile.call(this, tileCoord, state);
/**
* Image URI
*
* @private
* @type {string}
*/
this.src_ = src;
/**
* @private
* @type {Image}
*/
this.image_ = new Image();
if (crossOrigin !== null) {
this.image_.crossOrigin = crossOrigin;
}
/**
* @private
* @type {Object.<number, Image>}
*/
this.imageByContext_ = {};
/**
* @private
* @type {Array.<ol.EventsKey>}
*/
this.imageListenerKeys_ = null;
/**
* @private
* @type {ol.TileLoadFunctionType}
*/
this.tileLoadFunction_ = tileLoadFunction;
};
ol.inherits(ol.ImageTile, ol.Tile);
/**
* @inheritDoc
*/
ol.ImageTile.prototype.disposeInternal = function() {
if (this.state == ol.TileState.LOADING) {
this.unlistenImage_();
}
if (this.interimTile) {
this.interimTile.dispose();
}
this.state = ol.TileState.ABORT;
this.changed();
ol.Tile.prototype.disposeInternal.call(this);
};
/**
* Get the image element for this tile.
* @inheritDoc
* @api
*/
ol.ImageTile.prototype.getImage = function(opt_context) {
if (opt_context !== undefined) {
var image;
var key = ol.getUid(opt_context);
if (key in this.imageByContext_) {
return this.imageByContext_[key];
} else if (ol.object.isEmpty(this.imageByContext_)) {
image = this.image_;
} else {
image = /** @type {Image} */ (this.image_.cloneNode(false));
}
this.imageByContext_[key] = image;
return image;
} else {
return this.image_;
}
};
/**
* @inheritDoc
*/
ol.ImageTile.prototype.getKey = function() {
return this.src_;
};
/**
* Tracks loading or read errors.
*
* @private
*/
ol.ImageTile.prototype.handleImageError_ = function() {
this.state = ol.TileState.ERROR;
this.unlistenImage_();
this.changed();
};
/**
* Tracks successful image load.
*
* @private
*/
ol.ImageTile.prototype.handleImageLoad_ = function() {
if (this.image_.naturalWidth && this.image_.naturalHeight) {
this.state = ol.TileState.LOADED;
} else {
this.state = ol.TileState.EMPTY;
}
this.unlistenImage_();
this.changed();
};
/**
* 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.
* @api
*/
ol.ImageTile.prototype.load = function() {
if (this.state == ol.TileState.IDLE || this.state == ol.TileState.ERROR) {
this.state = ol.TileState.LOADING;
this.changed();
goog.DEBUG && console.assert(!this.imageListenerKeys_,
'this.imageListenerKeys_ should be null');
this.imageListenerKeys_ = [
ol.events.listenOnce(this.image_, ol.events.EventType.ERROR,
this.handleImageError_, this),
ol.events.listenOnce(this.image_, ol.events.EventType.LOAD,
this.handleImageLoad_, this)
];
this.tileLoadFunction_(this, this.src_);
}
};
/**
* Discards event handlers which listen for load completion or errors.
*
* @private
*/
ol.ImageTile.prototype.unlistenImage_ = function() {
this.imageListenerKeys_.forEach(ol.events.unlistenByKey);
this.imageListenerKeys_ = null;
};