sebastian-software/core

/*
==================================================================================================
  Core - JavaScript Foundation
  Copyright 2010-2012 Zynga Inc.
  Copyright 2012-2014 Sebastian Werner
==================================================================================================
*/

"use strict";

(function(global)
{
    // Dynamic URI can be shared because we do not support reloading files
    var dynamicExtension = "?r=" + Date.now();

    /**
     * Image loader with support for load callback.
     */
    core.Module("core.io.Image",
    {
        /** Whether the loader supports parallel requests. Always true for images. */
        SUPPORTS_PARALLEL : true,

        /**
         * Loads an image with the given @uri {String} and fires a @callback {Function} (in @context {Object?}) when the image was loaded.
         * Optionally appends an random `GET` parameter to omit caching when @nocache {Boolean?false} is enabled.
         */
        load : function(uri, callback, context, nocache)
        {
            if (jasy.Env.isSet("debug"))
            {
                core.Assert.isType(uri, "String");

                if (callback != null) {
                    core.Assert.isType(callback, "Function", "Invalid callback method!");
                }

                if (context != null) {
                    core.Assert.isType(context, "Object", "Invalid callback context!");
                }

                if (nocache != null) {
                    core.Assert.isType(nocache, "Boolean");
                }
            }

            if (core.io.Util.isRelativeUrl(uri)) {
                uri = jasy.Env.getValue("jasy.url") + uri;
            }

            var img = new Image;

            img.onload = img.onerror = function(e)
            {
                img.onload = img.onerror = null;

                var errornous = (e||global.event).type === "error";
                if (jasy.Env.isSet("debug") && errornous) {
                    console.warn("Could not load image: " + uri);
                }

                if (callback)
                {
                    callback.call(context || global, uri, errornous, {
                        node: img,
                        width : img.naturalWidth || img.width || 0,
                        height : img.naturalHeight || img.height || 0
                    });
                }
            };

            img.src = uri + (nocache ? dynamicExtension : "");
        }
    });
})(core.Main.getGlobal());