Fix zoom box sizes for tagged equations in HTML-CSS and NativeMML output. Issue #824.

Author: dpvc

unpacked/jax/output/HTML-CSS/jax.js

@@ -777,15 +777,18 @@
       this.idPostfix = "-zoom"; jax.root.toHTML(span,span); this.idPostfix = "";
       this.zoomScale = 1;
 
-      var width = jax.root.HTMLspanElement().bbox.width;
+      var width = jax.root.HTMLspanElement().bbox.width, cwidth;
       if (width) {
         //  Handle full-width displayed equations
         //  FIXME: this is a hack for now
         span.style.width = Math.floor(Mw-1.5*HTMLCSS.em)+"px"; span.style.display="inline-block";
         var id = (jax.root.id||"MathJax-Span-"+jax.root.spanID)+"-zoom";
         var child = document.getElementById(id).firstChild;
         while (child && child.style.width !== width) {child = child.nextSibling}
-        if (child) {child.style.width = "100%"}
+        if (child) {
+          var cwidth = child.offsetWidth; child.style.width = "100%";
+          if (cwidth > Mw) {span.style.width = (cwidth+100)+"px"}
+        }
       }
       //
       //  Get height and width of zoomed math and original math

unpacked/jax/output/NativeMML/jax.js

@@ -432,6 +432,7 @@
     Zoom: function (jax,span,math,Mw,Mh) {
       jax.root.toNativeMML(span);
       if (this.msieIE8HeightBug) {span.style.position = "absolute"}
+      if (nMML.widthBug) {span.style.width = span.parentNode.style.width = ""}
       var mW = math.offsetWidth  || math.scrollWidth,
           mH = math.offsetHeight || math.scrollHeight;
       var zW = span.offsetWidth, zH = span.offsetHeight;