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fast-preview.js (5486B)

---

 /* -*- Mode: Javascript; indent-tabs-mode:nil; js-indent-level: 2 -*- */
 /* vim: set ts=2 et sw=2 tw=80: */
 
 /*************************************************************
  *
  *  MathJax/extensions/fast-preview.js
  *  
  *  Implements a fast preview using the PreviewHTML output jax
  *  and then a slower update to the more accurate HTML-CSS output
  *  (or whatever the user has selected).
  *  
  *  ---------------------------------------------------------------------
  *  
  *  Copyright (c) 2014-2015 The MathJax Consortium
  * 
  *  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.
  */
 
 (function (HUB,HTML,BROWSER) {
   
   var SETTINGS = HUB.config.menuSettings;
   var JAX = MathJax.OutputJax;
   var msieColorBug = BROWSER.isMSIE && (document.documentMode||0) < 8;
 
   var FastPreview = MathJax.Extension["fast-preview"] = {
     version: "2.6.0",
     enabled: true,
 
     //
     //  Configuration for the chunking of the main output
     //  after the previews have been created, and other configuration.
     //
     config: HUB.CombineConfig("fast-preview",{
       Chunks: {EqnChunk: 10000, EqnChunkFactor: 1, EqnChunkDelay: 0},
       color: "inherit!important",
       updateTime: 30, updateDelay: 6,
       messageStyle: "none",
       disabled: BROWSER.isMSIE && !BROWSER.versionAtLeast("8.0")
     }),
 
     //
     //  Ajust the chunking of the output jax
     //
     Config: function () {
       if (HUB.config["CHTML-preview"])
         MathJax.Hub.Config({"fast-preview": HUB.config["CHTML-preview"]});
       var update, delay, style, done, saved;
       var config = this.config;
 
       if (!config.disabled && SETTINGS.FastPreview == null)
         HUB.Config({menuSettings:{FastPreview:true}});
       if (SETTINGS.FastPreview) {
         MathJax.Ajax.Styles({".MathJax_Preview .MJXf-math":{color:config.color}});
         HUB.Config({"HTML-CSS": config.Chunks, CommonHTML: config.Chunks, SVG: config.Chunks});
       }
       HUB.Register.MessageHook("Begin Math Output",function () {
         if (!done && FastPreview.Active()) {
           update = HUB.processUpdateTime; delay = HUB.processUpdateDelay;
           style = HUB.config.messageStyle;
           HUB.processUpdateTime = config.updateTime;
           HUB.processUpdateDelay = config.updateDelay;
           HUB.Config({messageStyle: config.messageStyle});
           MathJax.Message.Clear(0,0);
           saved = true;
         }
       });
       HUB.Register.MessageHook("End Math Output",function () {
         if (!done && saved) {
           HUB.processUpdateTime = update;
           HUB.processUpdateDelay = delay;
           HUB.Config({messageStyle: style});
           done = true;
         }
       });
     },
     
     //
     //  Allow page to override user settings (for things like editor previews)
     //
     Disable: function () {this.enabled = false},
     Enable: function () {this.enabled = true},
     
     Active: function () {
       return SETTINGS.FastPreview && this.enabled &&
              !(JAX[SETTINGS.renderer]||{}).noFastPreview;
     },
 
     //
     //  Insert a preview span, if there isn't one already,
     //  and call the PreviewHTML output jax to create the preview
     //
     Preview: function (data) {
       if (!this.Active()) return;
       var preview = data.script.MathJax.preview || data.script.previousSibling;
       if (!preview || preview.className !== MathJax.Hub.config.preRemoveClass) {
         preview = HTML.Element("span",{className:MathJax.Hub.config.preRemoveClass});
         data.script.parentNode.insertBefore(preview,data.script);
         data.script.MathJax.preview = preview;
       }
       preview.innerHTML = "";
       preview.style.color = (msieColorBug ? "black" : "inherit");
       return this.postFilter(preview,data);
     },
     postFilter: function (preview,data) {
       //
       //  Load the PreviewHTML jax if it is not already loaded
       //
       if (!data.math.root.toPreviewHTML) {
         var queue = MathJax.Callback.Queue();
         queue.Push(
           ["Require",MathJax.Ajax,"[MathJax]/jax/output/PreviewHTML/config.js"],
           ["Require",MathJax.Ajax,"[MathJax]/jax/output/PreviewHTML/jax.js"]
         );
         HUB.RestartAfter(queue.Push({}));
       }
       data.math.root.toPreviewHTML(preview);
     },
 
     //
     //  Hook into the input jax postFilter to create the previews as
     //  the input jax are processed.
     //
     Register: function (name) {
       HUB.Register.StartupHook(name+" Jax Require",function () {
         var jax = MathJax.InputJax[name];
         jax.postfilterHooks.Add(["Preview",MathJax.Extension["fast-preview"]],50);
       });
     }
   }
 
   //
   //  Hook into each input jax
   //
   FastPreview.Register("TeX");
   FastPreview.Register("MathML");
   FastPreview.Register("AsciiMath");
   
   HUB.Register.StartupHook("End Config",["Config",FastPreview]);
   
   HUB.Startup.signal.Post("fast-preview Ready");
 
 })(MathJax.Hub,MathJax.HTML,MathJax.Hub.Browser);
 
 MathJax.Ajax.loadComplete("[MathJax]/extensions/fast-preview.js");