From bcdb2f104842371920e70ff4a6aa822f0ae4becc Mon Sep 17 00:00:00 2001
From: "Davide P. Cervone" <dpvc@union.edu>
Date: Mon, 13 Jul 2015 10:52:04 -0400
Subject: [PATCH] Don't allow labels to overlap equations in HTML-CSS mode. 
 Because HTML-CSS allows tables that fill 100% of the width, making this work
 for centered equations is sub-optimal as we have to leave space on both sides
 of the equation to balance the label width.  Issue #596.

---
 .../jax/output/HTML-CSS/autoload/mtable.js    | 29 ++++++++++++-------
 unpacked/jax/output/HTML-CSS/jax.js           |  4 +--
 2 files changed, 20 insertions(+), 13 deletions(-)

diff --git a/unpacked/jax/output/HTML-CSS/autoload/mtable.js b/unpacked/jax/output/HTML-CSS/autoload/mtable.js
index 855a08e7d..3e6759fae 100644
--- a/unpacked/jax/output/HTML-CSS/autoload/mtable.js
+++ b/unpacked/jax/output/HTML-CSS/autoload/mtable.js
@@ -428,24 +428,31 @@ MathJax.Hub.Register.StartupHook("HTML-CSS Jax Ready",function () {
         if (indent.indentshiftfirst !== MML.INDENTSHIFT.INDENTSHIFT) {indent.indentshift = indent.indentshiftfirst}
         if (indent.indentshift === "auto") {indent.indentshift = "0"}
         var shift = HTMLCSS.length2em(indent.indentshift,mu,HTMLCSS.cwidth);
-        var labelshift = HTMLCSS.length2em(values.minlabelspacing,mu,HTMLCSS.cwidth);
-        if (this.displayIndent !== "0") {
-          var dIndent = HTMLCSS.length2em(this.displayIndent,mu,HTMLCSS.cwidth);
-          shift += (indent.indentAlign === MML.INDENTALIGN.RIGHT ? -dIndent: dIndent);
+        var labelspace = HTMLCSS.length2em(values.minlabelspacing,mu,HTMLCSS.cwidth);
+        var labelW = labelspace + C[LABEL].bbox.w, labelshift = 0, tw = mw;
+        var dIndent = HTMLCSS.length2em(this.displayIndent,mu,HTMLCSS.cwidth);
+        var s = (CALIGN[LABEL] === MML.INDENTALIGN.RIGHT ? -1 : 1);
+        if (indent.indentalign === MML.INDENTALIGN.CENTER) {
+          tw += 2 * (labelW - s*(shift + dIndent));
+          shift += dIndent;
+        } else if (CALIGN[LABEL] === indent.indentalign) {
+          if (dIndent < 0) {labelshift = s*dIndent; dIndent = 0}
+          shift += s*dIndent; if (labelW > s*shift) shift = s*labelW; shift += labelshift;
+          tw += s*shift;
+        } else {
+          tw += labelW - s*shift + dIndent;
+          shift -= s*dIndent;
         }
         var eqn = HTMLCSS.createStack(span,false,"100%");
         HTMLCSS.addBox(eqn,stack); HTMLCSS.alignBox(stack,indent.indentalign,0,shift);
-
         C[LABEL].parentNode.parentNode.removeChild(C[LABEL].parentNode);
         HTMLCSS.addBox(eqn,C[LABEL]); HTMLCSS.alignBox(C[LABEL],CALIGN[LABEL],0);
         if (HTMLCSS.msieRelativeWidthBug) {stack.style.top = C[LABEL].style.top = ""}
         if (hasRelativeWidth) {stack.style.width = values.width; span.bbox.width = "100%"}
-        C[LABEL].style.marginRight = C[LABEL].style.marginLeft = HTMLCSS.Em(labelshift);
-        if (indent.indentalign === MML.INDENTALIGN.CENTER) {mw += 4*labelshift + 2*C[LABEL].bbox.w}
-          else if (indent.indentalign !== CALIGN[LABEL]) {mw += 2*labelshift + C[LABEL].bbox.w}
-        mw = Math.max(0,mw+shift); span.bbox.tw = mw + 2*labelshift;
-        span.style.minWidth = span.bbox.minWidth = HTMLCSS.Em(mw);
-        eqn.style.minWidth = eqn.bbox.minWidth = HTMLCSS.Em(mw/HTMLCSS.scale);
+        C[LABEL].style[s === 1 ? "marginLeft" : "marginRight"] = HTMLCSS.Em(s*labelshift);
+        span.bbox.tw = tw;
+        span.style.minWidth = span.bbox.minWidth = HTMLCSS.Em(tw);
+        eqn.style.minWidth = eqn.bbox.minWidth = HTMLCSS.Em(tw/scale);
       }
       //
       //  Finish the table
diff --git a/unpacked/jax/output/HTML-CSS/jax.js b/unpacked/jax/output/HTML-CSS/jax.js
index b4888426c..2250af1d4 100644
--- a/unpacked/jax/output/HTML-CSS/jax.js
+++ b/unpacked/jax/output/HTML-CSS/jax.js
@@ -2936,10 +2936,10 @@
             node.style.textAlign = values.indentalign;
             // ### FIXME: make percentage widths respond to changes in container
             if (shift) {
-              shift *= HTMLCSS.em/HTMLCSS.outerEm;
+              shift *= HTMLCSS.scale;
               HUB.Insert(span.style,({
                 left: {marginLeft: HTMLCSS.Em(shift)},
-                right: {marginLeft: HTMLCSS.Em(Math.max(0,span.bbox.w+shift)), marginRight: HTMLCSS.Em(-shift)},
+                right: {marginRight: HTMLCSS.Em(-shift)},
                 center: {marginLeft: HTMLCSS.Em(shift), marginRight: HTMLCSS.Em(-shift)}
               })[values.indentalign]);
               //