Add config option for matching font heights in NativeMML and HTML-CSS output (can't do it for SVG, since we aren't using native fonts)

Author: dpvc

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: {
+    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
     preferredFont: "TeX",           // preferred local font (TeX or STIX)

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

@@ -534,7 +534,8 @@
           ex = this.defaultEx; em = this.defaultEm;
           if (relwidth) {maxwidth = this.defaultWidth}
         }
-        scale = Math.floor(Math.max(this.config.minScaleAdjust/100,(ex/this.TeX.x_height)/em) * this.config.scale);
+        scale = (this.config.matchFontHeight ? ex/this.TeX.x_height/em : 1);
+        scale = Math.floor(Math.max(this.config.minScaleAdjust/100,scale)*this.config.scale);
         jax.HTMLCSS.scale = scale/100; jax.HTMLCSS.fontSize = scale+"%";
         jax.HTMLCSS.em = jax.HTMLCSS.outerEm = em; this.em = em * scale/100; jax.HTMLCSS.ex = ex;
         jax.HTMLCSS.lineWidth = (linebreak ? this.length2em(width,1,maxwidth/this.em) : 1000000);
@@ -584,7 +585,7 @@
       this.em = MML.mbase.prototype.em = jax.HTMLCSS.em * jax.HTMLCSS.scale; 
       this.outerEm = jax.HTMLCSS.em; this.scale = jax.HTMLCSS.scale;
       this.linebreakWidth = jax.HTMLCSS.lineWidth;
-      span.style.fontSize = jax.HTMLCSS.fontSize;
+      if (this.scale !== 1) {span.style.fontSize = jax.HTMLCSS.fontSize}
       //
       //  Typeset the math
       //

unpacked/jax/output/NativeMML/config.js

@@ -32,6 +32,7 @@ MathJax.OutputJax.NativeMML = MathJax.OutputJax({
   extensionDir: MathJax.OutputJax.extensionDir + "/NativeMML",
 
   config: {
+    matchFontHeight: true,   // try to match math font height to surrounding font?
     scale: 100,              // scaling factor for all math
     minScaleAdjust: 50,      // minimum scaling to adjust to surrounding text
                              //  (since the code for that is a bit delicate)

unpacked/jax/output/NativeMML/jax.js

@@ -257,11 +257,12 @@
           ex = test.firstChild.offsetWidth/60;
           mex = test.lastChild.offsetWidth/60;
           if (ex === 0 || ex === "NaN") {ex = this.defaultEx; mex = this.defaultMEx}
-          scale = (mex > 1 ? ex/mex : 1) * this.config.scale;
-          scale = Math.floor(Math.max(this.config.minScaleAdjust/100,scale));
-          jax.NativeMML.ex = ex; jax.NativeMML.scale = scale/100;
+          scale = (this.config.matchFontHeight && mex > 1 ? ex/mex : 1);
+          scale = Math.floor(Math.max(this.config.minScaleAdjust/100,scale) * this.config.scale);
+          jax.NativeMML.ex = ex;
         } else {scale = 100}
         jax.NativeMML.fontSize = scale+"%";
+        jax.NativeMML.scale = scale/100;
       }
       //
       //  Remove the test spans used for determining scales
@@ -286,9 +287,9 @@
       var jax = script.MathJax.elementJax, math = jax.root;
       var span = document.getElementById(jax.inputID+"-Frame"),
 	  container = span.firstChild, mspan = container.firstChild;
-      span.style.fontSize = jax.NativeMML.fontSize;
       this.ex = jax.NativeMML.ex || this.defaultEx;
       this.scale = jax.NativeMML.scale || 1;
+      if (this.scale !== 1) {span.style.fontSize = jax.NativeMML.fontSize}
       //
       //  Convert to MathML (if restarted, remove any partial math)
       //