From 1aa86d7cf6e493bd748b92c19f5e176334cacb20 Mon Sep 17 00:00:00 2001
From: "Davide P. Cervone" <dpvc@union.edu>
Date: Sun, 17 Aug 2014 14:14:39 -0400
Subject: [PATCH] Add noReflows flag to prevent taking measurements that cause
 reflows, when possible.  This provides a 30 to 40% speed improvement, but can
 cause poor results in some browsers.

---
 unpacked/jax/output/HTML-CSS/config.js | 1 +
 unpacked/jax/output/HTML-CSS/jax.js    | 9 ++++++---
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/unpacked/jax/output/HTML-CSS/config.js b/unpacked/jax/output/HTML-CSS/config.js
index b1aa6d59d..79512627a 100644
--- a/unpacked/jax/output/HTML-CSS/config.js
+++ b/unpacked/jax/output/HTML-CSS/config.js
@@ -35,6 +35,7 @@ MathJax.OutputJax["HTML-CSS"] = MathJax.OutputJax({
   webfontDir: MathJax.OutputJax.fontDir + "/HTML-CSS",      // font name added later
   
   config: {
+    noReflows: false,               // true will use internal measurements and avoid browser reflows
     matchFontHeight: true,          // try to match math font height to surrounding font?
     scale: 100, minScaleAdjust: 50, // global math scaling factor, and minimum adjusted scale factor
     availableFonts: ["STIX","TeX"], // list of local fonts to check for
diff --git a/unpacked/jax/output/HTML-CSS/jax.js b/unpacked/jax/output/HTML-CSS/jax.js
index a095e8f59..726d7076f 100644
--- a/unpacked/jax/output/HTML-CSS/jax.js
+++ b/unpacked/jax/output/HTML-CSS/jax.js
@@ -26,7 +26,6 @@
  *  limitations under the License.
  */
 
-
 (function (AJAX,HUB,HTMLCSS) {
   var MML, isMobile = HUB.Browser.isMobile;
 
@@ -177,6 +176,7 @@
     loadWebFont: function (font) {
       HUB.Startup.signal.Post("HTML-CSS Jax - Web-Font "+HTMLCSS.fontInUse+"/"+font.directory);
       var n = MESSAGE(["LoadWebFont","Loading web-font %1",HTMLCSS.fontInUse+"/"+font.directory]);
+      if (HTMLCSS.noReflows) return;
       var done = MathJax.Callback({}); // called when font is loaded
       var callback = MathJax.Callback(["loadComplete",this,font,n,done]);
       AJAX.timer.start(AJAX,[this.checkWebFont,font,callback],0,this.timeout);
@@ -832,6 +832,7 @@
     },
     
     getHD: function (span) {
+      if (span.bbox && this.config.noReflows) {return {h:span.bbox.h, d:span.bbox.d}}
       var position = span.style.position;
       span.style.position = "absolute";
       this.HDimg.style.height = "0px";
@@ -845,6 +846,7 @@
       return HD;
     },
     getW: function (span) {
+      if (span.bbox && this.config.noReflows) {return span.bbox.w}
       var W, H, w = (span.bbox||{}).w, start = span;
       if (span.bbox && span.bbox.exactW) {return w}
       if ((span.bbox && w >= 0 && !this.initialSkipBug && !this.msieItalicWidthBug) ||
@@ -886,7 +888,7 @@
       for (i = 0, m = SPANS.length; i < m; i++) {
         span = SPANS[i]; if (!span) continue;
         bbox = span.bbox; parent = this.parentNode(span);
-        if (bbox.exactW || bbox.width || bbox.w === 0 || bbox.isMultiline) {
+        if (bbox.exactW || bbox.width || bbox.w === 0 || bbox.isMultiline || this.config.noReflows) {
           if (!parent.bbox) {parent.bbox = bbox}
           continue;
         }
@@ -1077,7 +1079,8 @@
                 width:0, height:H, verticalAlign:D},
         bbox: {h:h, d:d, w:w, rw:w, lw:0, exactW:true}, noAdjust:true, HH:h+d, isMathJax:true
       });
-      if (w > 0 && rule.offsetWidth == 0) {rule.style.width = this.Em(w)}
+      // ### FIXME:  figure out which IE has this bug and make a flag for it
+      if (w > 0 && !this.noReflows && rule.offsetWidth == 0) {rule.style.width = this.Em(w)}
       if (span.isBox || span.className == "mspace") {span.bbox = rule.bbox, span.HH = h+d}
       return rule;
     },