Add a kludge to work around poor dimension measurements in bidi text in IE

Closes #1129

Author: marijnh

lib/codemirror.js

@@ -1022,7 +1022,9 @@ window.CodeMirror = (function() {
         }
       }
       if (j == vranges.length) vranges.push(top, bot);
-      data[i] = {left: size.left - outer.left, right: size.right - outer.left, top: j};
+      var right = size.right;
+      if (cur.measureRight) right = getRect(cur.measureRight).left;
+      data[i] = {left: size.left - outer.left, right: right - outer.left, top: j};
     }
     for (var i = 0, cur; i < data.length; ++i) if (cur = data[i]) {
       var vr = cur.top;
@@ -1085,10 +1087,9 @@ window.CodeMirror = (function() {
       if (part.from < ch && part.to > ch) return get(ch, rtl);
       var left = rtl ? part.to : part.from, right = rtl ? part.from : part.to;
       if (left == ch) {
-        // Opera and IE return bogus offsets and widths for edges
-        // where the direction flips, but only for the side with the
-        // lower level. So we try to use the side with the higher
-        // level.
+        // IE returns bogus offsets and widths for edges where the
+        // direction flips, but only for the side with the lower
+        // level. So we try to use the side with the higher level.
         if (i && part.level < (nb = order[i-1]).level) here = get(nb.level % 2 ? nb.from : nb.to - 1, true);
         else here = get(rtl && part.from != part.to ? ch - 1 : ch);
         if (rtl == linedir) main = here; else other = here;
@@ -3971,6 +3972,21 @@ window.CodeMirror = (function() {
     if (!builder.pre.firstChild && !lineIsHidden(cm.doc, realLine))
       builder.pre.appendChild(document.createTextNode("\u00a0"));
 
+    var order;
+    // Work around problem with the reported dimensions of single-char
+    // direction spans on IE (issue #1129). See also the comment in
+    // cursorCoords.
+    if (measure && ie && (order = getOrder(line))) {
+      var l = order.length - 1;
+      if (order[l].from == order[l].to) --l;
+      var last = order[l], prev = order[l - 1];
+      if (last.from + 1 == last.to && prev && last.level < prev.level) {
+        var span = measure[builder.pos - 1];
+        if (span) span.parentNode.insertBefore(span.measureRight = zeroWidthElement(cm.display.measure),
+                                               span.nextSibling);
+      }
+    }
+
     return builder.pre;
   }
 

test/test.js

@@ -984,7 +984,7 @@ testCM("verticalMovementCommandsWrapping", function(cm) {
 
 testCM("rtlMovement", function(cm) {
   forEach(["خحج", "خحabcخحج", "abخحخحجcd", "abخde", "abخح2342خ1حج", "خ1ح2خح3حxج",
-           "خحcd", "1خحcd", "abcdeح1ج", "خمرحبها مها!"], function(line) {
+           "خحcd", "1خحcd", "abcdeح1ج", "خمرحبها مها!", "foobarر"], function(line) {
     var inv = line.charAt(0) == "خ";
     cm.setValue(line + "\n"); cm.execCommand(inv ? "goLineEnd" : "goLineStart");
     var cursor = byClassName(cm.getWrapperElement(), "CodeMirror-cursor")[0];