Function patchDisplay

src/cm/codemirror.js:1169–1207

(from, to, intact)

    }

    function patchDisplay(from, to, intact) {
      function killNode(node) {
        var tmp = node.nextSibling;
        node.parentNode.removeChild(node);
        return tmp;
      }
      // The first pass removes the DOM nodes that aren't intact.
      if (!intact.length) removeChildren(lineDiv);
      else {
        var domPos = 0, curNode = lineDiv.firstChild, n;
        for (var i = 0; i < intact.length; ++i) {
          var cur = intact[i];
          while (cur.domStart > domPos) {curNode = killNode(curNode); domPos++;}
          for (var j = 0, e = cur.to - cur.from; j < e; ++j) {curNode = curNode.nextSibling; domPos++;}
        }
        while (curNode) curNode = killNode(curNode);
      }
      // This pass fills in the lines that actually changed.
      var nextIntact = intact.shift(), curNode = lineDiv.firstChild, j = from;
      doc.iter(from, to, function(line) {
        if (nextIntact && nextIntact.to == j) nextIntact = intact.shift();
        if (!nextIntact || nextIntact.from > j) {
          if (line.hidden) var lineElement = elt("pre");
          else {
            var lineElement = lineContent(line);
            if (line.className) lineElement.className = line.className;
            // Kludge to make sure the styled element lies behind the selection (by z-index)
            if (line.bgClassName) {
              var pre = elt("pre", "\u00a0", line.bgClassName, "position: absolute; left: 0; right: 0; top: 0; bottom: 0; z-index: -2");
              lineElement = elt("div", [pre, lineElement], null, "position: relative");
            }
          }
          lineDiv.insertBefore(lineElement, curNode);
        } else {
          curNode = curNode.nextSibling;
        }
        ++j;
      });
    }

    function updateGutter() {
      if (!options.gutter && !options.lineNumbers) return;