goog.provide('ol.Image');
goog.require('goog.asserts');
goog.require('goog.events');
goog.require('goog.events.EventType');
goog.require('goog.object');
goog.require('ol.ImageBase');
goog.require('ol.ImageState');
goog.require('ol.extent');
/**
* @constructor
* @extends {ol.ImageBase}
* @param {ol.Extent} extent Extent.
* @param {Array.<number>|undefined} resolution Resolution.
* @param {number} pixelRatio Pixel ratio.
* @param {Array.<ol.Attribution>} attributions Attributions.
* @param {string} src Image source URI.
* @param {?string} crossOrigin Cross origin.
* @param {ol.ImageLoadFunctionType} imageLoadFunction Image load function.
*/
ol.Image = function(extent, resolution, pixelRatio, attributions, src,
crossOrigin, imageLoadFunction) {
goog.base(this, extent, resolution, pixelRatio, ol.ImageState.IDLE,
attributions);
/**
* @private
* @type {string}
*/
this.src_ = src;
/**
* @private
* @type {Image}
*/
this.image_ = new Image();
Iif (crossOrigin) {
this.image_.crossOrigin = crossOrigin;
}
/**
* @private
* @type {Object.<number, Image>}
*/
this.imageByContext_ = {};
/**
* @private
* @type {Array.<goog.events.Key>}
*/
this.imageListenerKeys_ = null;
/**
* @protected
* @type {ol.ImageState}
*/
this.state = ol.ImageState.IDLE;
/**
* @private
* @type {ol.ImageLoadFunctionType}
*/
this.imageLoadFunction_ = imageLoadFunction;
};
goog.inherits(ol.Image, ol.ImageBase);
/**
* Get the HTML image element (may be a Canvas, Image, or Video).
* @param {Object=} opt_context Object.
* @return {HTMLCanvasElement|Image|HTMLVideoElement} Image.
* @api
*/
ol.Image.prototype.getImage = function(opt_context) {
Iif (opt_context !== undefined) {
var image;
var key = goog.getUid(opt_context);
if (key in this.imageByContext_) {
return this.imageByContext_[key];
} else if (goog.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_;
}
};
/**
* Tracks loading or read errors.
*
* @private
*/
ol.Image.prototype.handleImageError_ = function() {
this.state = ol.ImageState.ERROR;
this.unlistenImage_();
this.changed();
};
/**
* Tracks successful image load.
*
* @private
*/
ol.Image.prototype.handleImageLoad_ = function() {
Iif (this.resolution === undefined) {
this.resolution = [
ol.extent.getWidth(this.extent) / this.image_.width,
ol.extent.getHeight(this.extent) / this.image_.height
];
}
this.state = ol.ImageState.LOADED;
this.unlistenImage_();
this.changed();
};
/**
* Load not yet loaded URI.
*/
ol.Image.prototype.load = function() {
Eif (this.state == ol.ImageState.IDLE) {
this.state = ol.ImageState.LOADING;
this.changed();
goog.asserts.assert(!this.imageListenerKeys_,
'this.imageListenerKeys_ should be null');
this.imageListenerKeys_ = [
goog.events.listenOnce(this.image_, goog.events.EventType.ERROR,
this.handleImageError_, false, this),
goog.events.listenOnce(this.image_, goog.events.EventType.LOAD,
this.handleImageLoad_, false, this)
];
this.imageLoadFunction_(this, this.src_);
}
};
/**
* Discards event handlers which listen for load completion or errors.
*
* @private
*/
ol.Image.prototype.unlistenImage_ = function() {
goog.asserts.assert(this.imageListenerKeys_,
'this.imageListenerKeys_ should not be null');
this.imageListenerKeys_.forEach(goog.events.unlistenByKey);
this.imageListenerKeys_ = null;
};
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