From 72a6a670bfd3d07cd3369b41b4c87600a838cce2 Mon Sep 17 00:00:00 2001
From: "Davide P. Cervone" <dpvc@union.edu>
Date: Mon, 18 Aug 2014 11:09:09 -0400
Subject: [PATCH 1/2] Add ability to process units of px in \\[...] (not
 particularly accurate, however).  Issue #890

---
 unpacked/jax/input/TeX/jax.js | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/unpacked/jax/input/TeX/jax.js b/unpacked/jax/input/TeX/jax.js
index 2c8166f54..bc1cd5873 100644
--- a/unpacked/jax/input/TeX/jax.js
+++ b/unpacked/jax/input/TeX/jax.js
@@ -1654,8 +1654,7 @@
       var n;
       if (this.string.charAt(this.i) === "[") {
         n = this.GetBrackets(name,"").replace(/ /g,"");
-        if (n &&
-            !n.match(/^((-?(\.\d+|\d+(\.\d*)?))(pt|em|ex|mu|mm|cm|in|pc))$/)) {
+        if (n && !this.matchDimen(n)) {
           TEX.Error(["BracketMustBeDimension",
                      "Bracket argument to %1 must be a dimension",name]);
         }
@@ -1676,12 +1675,16 @@
       }
     },
     emPerInch: 7.2,
+    matchDimen: function (dim) {
+      return dim.match(/^(-?(?:\.\d+|\d+(?:\.\d*)?))(px|pt|em|ex|mu|pc|in|mm|cm)$/);
+    },
     dimen2em: function (dim) {
-      var match = dim.match(/^(-?(?:\.\d+|\d+(?:\.\d*)?))(pt|em|ex|mu|pc|in|mm|cm)/);
+      var match = this.matchDimen(dim);
       var m = parseFloat(match[1]||"1"), unit = match[2];
       if (unit === "em") {return m}
       if (unit === "ex") {return m * .43}
       if (unit === "pt") {return m / 10}                    // 10 pt to an em
+      if (unit === "px") {return m / 12}                    // assume 12px per em (hack)
       if (unit === "pc") {return m * 1.2}                   // 12 pt to a pc
       if (unit === "in") {return m * this.emPerInch}
       if (unit === "cm") {return m * this.emPerInch / 2.54} // 2.54 cm to an inch

From 4db6b017ee5fc0e1cf3d3864aafb9c9500f914e1 Mon Sep 17 00:00:00 2001
From: "Davide P. Cervone" <dpvc@union.edu>
Date: Mon, 18 Aug 2014 11:29:21 -0400
Subject: [PATCH 2/2] Make px-per-inch configurable and use 72dpi (pt = px in
 this case)

---
 unpacked/jax/input/TeX/jax.js | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/unpacked/jax/input/TeX/jax.js b/unpacked/jax/input/TeX/jax.js
index bc1cd5873..20c38b14b 100644
--- a/unpacked/jax/input/TeX/jax.js
+++ b/unpacked/jax/input/TeX/jax.js
@@ -1675,6 +1675,7 @@
       }
     },
     emPerInch: 7.2,
+    pxPerInch: 72,
     matchDimen: function (dim) {
       return dim.match(/^(-?(?:\.\d+|\d+(?:\.\d*)?))(px|pt|em|ex|mu|pc|in|mm|cm)$/);
     },
@@ -1684,8 +1685,8 @@
       if (unit === "em") {return m}
       if (unit === "ex") {return m * .43}
       if (unit === "pt") {return m / 10}                    // 10 pt to an em
-      if (unit === "px") {return m / 12}                    // assume 12px per em (hack)
       if (unit === "pc") {return m * 1.2}                   // 12 pt to a pc
+      if (unit === "px") {return m * this.emPerInch / this.pxPerInch}
       if (unit === "in") {return m * this.emPerInch}
       if (unit === "cm") {return m * this.emPerInch / 2.54} // 2.54 cm to an inch
       if (unit === "mm") {return m * this.emPerInch / 25.4} // 10 mm to a cm