Reinstate the fixedGutter option

Author: marijnh

doc/manual.html

@@ -222,6 +222,11 @@ <h2 id="config">Configuration</h2>
       names are the keys passed
       to <a href="#setGutterMarker"><code>setGutterMarker</code></a>.</dd>
 
+      <dt id="option_fixedGutter"><code>fixedGutter (boolean)</code></dt>
+      <dd>Determines whether the gutter scrolls along with the content
+      horizontally (false) or whether it stays fixed during horizontal
+      scrolling (true, the default).</dd>
+
       <dt id="option_readOnly"><code>readOnly (boolean)</code></dt>
       <dd>This disables editing of the editor content by the user. If
       the special value <code>"nocursor"</code> is given (instead of

lib/codemirror.js

@@ -358,13 +358,14 @@ window.CodeMirror = (function() {
 
   function alignHorizontally(cm) {
     var display = cm.display;
-    if (!display.alignWidgets && !display.gutters.firstChild) return;
+    if (!display.alignWidgets && (!display.gutters.firstChild || !cm.options.fixedGutter)) return;
     var comp = compensateForHScroll(display) - display.scroller.scrollLeft + cm.view.scrollLeft;
     var gutterW = display.gutters.offsetWidth, l = comp + "px";
     for (var n = display.lineDiv.firstChild; n; n = n.nextSibling) if (n.alignable) {
       for (var i = 0, a = n.alignable; i < a.length; ++i) a[i].style.left = l;
     }
-    display.gutters.style.left = (comp + gutterW) + "px";
+    if (cm.options.fixedGutter)
+      display.gutters.style.left = (comp + gutterW) + "px";
   }
 
   function maybeUpdateLineNumberWidth(cm) {
@@ -428,7 +429,8 @@ window.CodeMirror = (function() {
 
     if (changes && maybeUpdateLineNumberWidth(cm))
       changes = true;
-    display.sizer.style.marginLeft = display.scrollbarH.style.left = display.gutters.offsetWidth + "px";
+    var gutterW = display.sizer.style.marginLeft = display.gutters.offsetWidth + "px";
+    display.scrollbarH.style.left = cm.options.fixedGutter ? gutterW : "0";
 
     // When merged lines are present, the line that needs to be
     // redrawn might not be the one that was changed.
@@ -616,8 +618,8 @@ window.CodeMirror = (function() {
     var wrap = elt("div", null, line.wrapClass, "position: relative");
     if (cm.options.lineNumbers || markers) {
       var gutterWrap = wrap.appendChild(elt("div", null, null, "position: absolute; left: " +
-                                            dims.fixedPos + "px"));
-      wrap.alignable = [gutterWrap];
+                                            (cm.options.fixedGutter ? dims.fixedPos : -dims.gutterTotalWidth) + "px"));
+      if (cm.options.fixedGutter) wrap.alignable = [gutterWrap];
       if (cm.options.lineNumbers && (!markers || !markers["CodeMirror-linenumbers"]))
         wrap.lineNumber = gutterWrap.appendChild(
           elt("div", lineNumberFor(cm.options, lineNo),
@@ -2883,6 +2885,10 @@ window.CodeMirror = (function() {
     setGuttersForLineNumbers(cm.options);
     guttersChanged(cm);
   }, true);
+  option("fixedGutter", true, function(cm, val) {
+    cm.display.gutters.style.left = val ? compensateForHScroll(cm.display) + "px" : "0";
+    cm.refresh();
+  }, true);
   option("lineNumbers", false, function(cm) {
     setGuttersForLineNumbers(cm.options);
     guttersChanged(cm);