Function updateSelection

mini-code-editor/cm/lib/codemirror.js:1124–1161

()

      return resized;
    }
    function updateSelection() {
      var collapsed = posEq(sel.from, sel.to);
      var fromPos = localCoords(sel.from, true);
      var toPos = collapsed ? fromPos : localCoords(sel.to, true);
      var headPos = sel.inverted ? fromPos : toPos, th = textHeight();
      var wrapOff = eltOffset(wrapper), lineOff = eltOffset(lineDiv);
      inputDiv.style.top = Math.max(0, Math.min(scroller.offsetHeight, headPos.y + lineOff.top - wrapOff.top)) + "px";
      inputDiv.style.left = Math.max(0, Math.min(scroller.offsetWidth, headPos.x + lineOff.left - wrapOff.left)) + "px";
      if (collapsed) {
        cursor.style.top = headPos.y + "px";
        cursor.style.left = (options.lineWrapping ? Math.min(headPos.x, lineSpace.offsetWidth) : headPos.x) + "px";
        cursor.style.display = "";
        selectionDiv.style.display = "none";
      } else {
        var sameLine = fromPos.y == toPos.y, html = "";
        var clientWidth = lineSpace.clientWidth || lineSpace.offsetWidth;
        var clientHeight = lineSpace.clientHeight || lineSpace.offsetHeight;
        function add(left, top, right, height) {
          var rstyle = quirksMode ? "width: " + (!right ? clientWidth : clientWidth - right - left) + "px"
                                  : "right: " + right + "px";
          html += '<div class="CodeMirror-selected" style="position: absolute; left: ' + left +
            'px; top: ' + top + 'px; ' + rstyle + '; height: ' + height + 'px"></div>';
        }
        if (sel.from.ch && fromPos.y >= 0) {
          var right = sameLine ? clientWidth - toPos.x : 0;
          add(fromPos.x, fromPos.y, right, th);
        }
        var middleStart = Math.max(0, fromPos.y + (sel.from.ch ? th : 0));
        var middleHeight = Math.min(toPos.y, clientHeight) - middleStart;
        if (middleHeight > 0.2 * th)
          add(0, middleStart, 0, middleHeight);
        if ((!sameLine || !sel.from.ch) && toPos.y < clientHeight - .5 * th)
          add(0, toPos.y, clientWidth - toPos.x, th);
        selectionDiv.innerHTML = html;
        cursor.style.display = "none";
        selectionDiv.style.display = "";
      }
    }

    function setShift(val) {
      if (val) shiftSelecting = shiftSelecting || (sel.inverted ? sel.to : sel.from);