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Diffstat (limited to 'contexts/data/lib/closure-library/closure/goog/net/imageloader.js')
| -rw-r--r-- | contexts/data/lib/closure-library/closure/goog/net/imageloader.js | 292 |
1 files changed, 0 insertions, 292 deletions
diff --git a/contexts/data/lib/closure-library/closure/goog/net/imageloader.js b/contexts/data/lib/closure-library/closure/goog/net/imageloader.js deleted file mode 100644 index 5cd2a5f..0000000 --- a/contexts/data/lib/closure-library/closure/goog/net/imageloader.js +++ /dev/null @@ -1,292 +0,0 @@ -// Copyright 2008 The Closure Library Authors. All Rights Reserved. -// -// Licensed under the Apache License, Version 2.0 (the "License"); -// you may not use this file except in compliance with the License. -// You may obtain a copy of the License at -// -// http://www.apache.org/licenses/LICENSE-2.0 -// -// Unless required by applicable law or agreed to in writing, software -// distributed under the License is distributed on an "AS-IS" BASIS, -// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. -// See the License for the specific language governing permissions and -// limitations under the License. - -/** - * @fileoverview Image loader utility class. Useful when an application needs - * to preload multiple images, for example so they can be sized. - * - * @author attila@google.com (Attila Bodis) - * @author zachlloyd@google.com (Zachary Lloyd) - * @author jonemerson@google.com (Jon Emerson) - */ - -goog.provide('goog.net.ImageLoader'); - -goog.require('goog.array'); -goog.require('goog.dom'); -goog.require('goog.events.EventHandler'); -goog.require('goog.events.EventTarget'); -goog.require('goog.events.EventType'); -goog.require('goog.net.EventType'); -goog.require('goog.object'); -goog.require('goog.userAgent'); - - - -/** - * Image loader utility class. Raises a {@link goog.events.EventType.LOAD} - * event for each image loaded, with an {@link Image} object as the target of - * the event, normalized to have {@code naturalHeight} and {@code naturalWidth} - * attributes. - * - * To use this class, run: - * - * <pre> - * var imageLoader = new goog.net.ImageLoader(); - * goog.events.listen(imageLoader, goog.net.EventType.COMPLETE, - * function(e) { ... }); - * imageLoader.addImage("image_id", "http://path/to/image.gif"); - * imageLoader.start(); - * </pre> - * - * The start() method must be called to start image loading. Images can be - * added and removed after loading has started, but only those images added - * before start() was called will be loaded until start() is called again. - * A goog.net.EventType.COMPLETE event will be dispatched only once all - * outstanding images have completed uploading. - * - * @param {Element=} opt_parent An optional parent element whose document object - * should be used to load images. - * @constructor - * @extends {goog.events.EventTarget} - */ -goog.net.ImageLoader = function(opt_parent) { - goog.events.EventTarget.call(this); - - /** - * Map of image IDs to their image src, used to keep track of the images to - * load. Once images have started loading, they're removed from this map. - * @type {!Object.<string, string>} - * @private - */ - this.imageIdToUrlMap_ = {}; - - /** - * Map of image IDs to their image element, used only for images that are in - * the process of loading. Used to clean-up event listeners and to know - * when we've completed loading images. - * @type {!Object.<string, !Element>} - * @private - */ - this.imageIdToImageMap_ = {}; - - /** - * Event handler object, used to keep track of onload and onreadystatechange - * listeners. - * @type {!goog.events.EventHandler} - * @private - */ - this.handler_ = new goog.events.EventHandler(this); - - /** - * The parent element whose document object will be used to load images. - * Useful if you want to load the images from a window other than the current - * window in order to control the Referer header sent when the image is - * loaded. - * @type {Element|undefined} - * @private - */ - this.parent_ = opt_parent; -}; -goog.inherits(goog.net.ImageLoader, goog.events.EventTarget); - - -/** - * An array of event types to listen to on images. This is browser dependent. - * Internet Explorer doesn't reliably raise LOAD events on images, so we must - * use READY_STATE_CHANGE. If the image is cached locally, IE won't fire the - * LOAD event while the onreadystate event is fired always. On the other hand, - * the ERROR event is always fired whenever the image is not loaded successfully - * no matter whether it's cached or not. - * @type {!Array.<string>} - * @private - */ -goog.net.ImageLoader.IMAGE_LOAD_EVENTS_ = [ - goog.userAgent.IE ? goog.net.EventType.READY_STATE_CHANGE : - goog.events.EventType.LOAD, - goog.net.EventType.ABORT, - goog.net.EventType.ERROR -]; - - -/** - * Adds an image to the image loader, and associates it with the given ID - * string. If an image with that ID already exists, it is silently replaced. - * When the image in question is loaded, the target of the LOAD event will be - * an {@code Image} object with {@code id} and {@code src} attributes based on - * these arguments. - * @param {string} id The ID of the image to load. - * @param {string|Image} image Either the source URL of the image or the HTML - * image element itself (or any object with a {@code src} property, really). - */ -goog.net.ImageLoader.prototype.addImage = function(id, image) { - var src = goog.isString(image) ? image : image.src; - if (src) { - // For now, we just store the source URL for the image. - this.imageIdToUrlMap_[id] = src; - } -}; - - -/** - * Removes the image associated with the given ID string from the image loader. - * If the image was previously loading, removes any listeners for its events - * and dispatches a COMPLETE event if all remaining images have now completed. - * @param {string} id The ID of the image to remove. - */ -goog.net.ImageLoader.prototype.removeImage = function(id) { - delete this.imageIdToUrlMap_[id]; - - var image = this.imageIdToImageMap_[id]; - if (image) { - delete this.imageIdToImageMap_[id]; - - // Stop listening for events on the image. - this.handler_.unlisten(image, goog.net.ImageLoader.IMAGE_LOAD_EVENTS_, - this.onNetworkEvent_); - - // If this was the last image, raise a COMPLETE event. - if (goog.object.isEmpty(this.imageIdToImageMap_) && - goog.object.isEmpty(this.imageIdToUrlMap_)) { - this.dispatchEvent(goog.net.EventType.COMPLETE); - } - } -}; - - -/** - * Starts loading all images in the image loader in parallel. Raises a LOAD - * event each time an image finishes loading, and a COMPLETE event after all - * images have finished loading. - */ -goog.net.ImageLoader.prototype.start = function() { - // Iterate over the keys, rather than the full object, to essentially clone - // the initial queued images in case any event handlers decide to add more - // images before this loop has finished executing. - var imageIdToUrlMap = this.imageIdToUrlMap_; - goog.array.forEach(goog.object.getKeys(imageIdToUrlMap), - function(id) { - var src = imageIdToUrlMap[id]; - if (src) { - delete imageIdToUrlMap[id]; - this.loadImage_(src, id); - } - }, this); -}; - - -/** - * Creates an {@code Image} object with the specified ID and source URL, and - * listens for network events raised as the image is loaded. - * @param {string} src The image source URL. - * @param {string} id The unique ID of the image to load. - * @private - */ -goog.net.ImageLoader.prototype.loadImage_ = function(src, id) { - if (this.isDisposed()) { - // When loading an image in IE7 (and maybe IE8), the error handler - // may fire before we yield JS control. If the error handler - // dispose the ImageLoader, this method will throw exception. - return; - } - - var image; - if (this.parent_) { - var dom = goog.dom.getDomHelper(this.parent_); - image = dom.createDom('img'); - } else { - image = new Image(); - } - - this.handler_.listen(image, goog.net.ImageLoader.IMAGE_LOAD_EVENTS_, - this.onNetworkEvent_); - this.imageIdToImageMap_[id] = image; - - image.id = id; - image.src = src; -}; - - -/** - * Handles net events (READY_STATE_CHANGE, LOAD, ABORT, and ERROR). - * @param {goog.events.Event} evt The network event to handle. - * @private - */ -goog.net.ImageLoader.prototype.onNetworkEvent_ = function(evt) { - var image = /** @type {Element} */ (evt.currentTarget); - - if (!image) { - return; - } - - if (evt.type == goog.net.EventType.READY_STATE_CHANGE) { - // This implies that the user agent is IE; see loadImage_(). - // Noe that this block is used to check whether the image is ready to - // dispatch the COMPLETE event. - if (image.readyState == goog.net.EventType.COMPLETE) { - // This is the IE equivalent of a LOAD event. - evt.type = goog.events.EventType.LOAD; - } else { - // This may imply that the load failed. - // Note that the image has only the following states: - // * uninitialized - // * loading - // * complete - // When the ERROR or the ABORT event is fired, the readyState - // will be either uninitialized or loading and we'd ignore those states - // since they will be handled separately (eg: evt.type = 'ERROR'). - - // Notes from MSDN : The states through which an object passes are - // determined by that object. An object can skip certain states - // (for example, interactive) if the state does not apply to that object. - // see http://msdn.microsoft.com/en-us/library/ms534359(VS.85).aspx - - // The image is not loaded, ignore. - return; - } - } - - // Add natural width/height properties for non-Gecko browsers. - if (typeof image.naturalWidth == 'undefined') { - if (evt.type == goog.events.EventType.LOAD) { - image.naturalWidth = image.width; - image.naturalHeight = image.height; - } else { - // This implies that the image fails to be loaded. - image.naturalWidth = 0; - image.naturalHeight = 0; - } - } - - // Redispatch the event on behalf of the image. Note that the external - // listener may dispose this instance. - this.dispatchEvent({type: evt.type, target: image}); - - if (this.isDisposed()) { - // If instance was disposed by listener, exit this function. - return; - } - - this.removeImage(image.id); -}; - - -/** @override */ -goog.net.ImageLoader.prototype.disposeInternal = function() { - delete this.imageIdToUrlMap_; - delete this.imageIdToImageMap_; - goog.dispose(this.handler_); - - goog.net.ImageLoader.superClass_.disposeInternal.call(this); -}; |