Function updateDisplay

GUI/codemirror/lib/codemirror.js:536–578

(cm, viewPort, forced)

  // unless forced is true.
  // Returns true if an actual update happened, false otherwise.
  function updateDisplay(cm, viewPort, forced) {
    var oldFrom = cm.display.viewFrom, oldTo = cm.display.viewTo, updated;
    var visible = visibleLines(cm.display, cm.doc, viewPort);
    for (var first = true;; first = false) {
      var oldWidth = cm.display.scroller.clientWidth;
      if (!updateDisplayInner(cm, visible, forced)) break;
      updated = true;

      // If the max line changed since it was last measured, measure it,
      // and ensure the document's width matches it.
      if (cm.display.maxLineChanged && !cm.options.lineWrapping)
        adjustContentWidth(cm);

      var barMeasure = measureForScrollbars(cm);
      updateSelection(cm);
      setDocumentHeight(cm, barMeasure);
      updateScrollbars(cm, barMeasure);
      if (webkit && cm.options.lineWrapping)
        checkForWebkitWidthBug(cm, barMeasure); // (Issue #2420)
      if (first && cm.options.lineWrapping && oldWidth != cm.display.scroller.clientWidth) {
        forced = true;
        continue;
      }
      forced = false;

      // Clip forced viewport to actual scrollable area.
      if (viewPort && viewPort.top != null)
        viewPort = {top: Math.min(barMeasure.docHeight - scrollerCutOff - barMeasure.clientHeight, viewPort.top)};
      // Updated line heights might result in the drawn area not
      // actually covering the viewport. Keep looping until it does.
      visible = visibleLines(cm.display, cm.doc, viewPort);
      if (visible.from >= cm.display.viewFrom && visible.to <= cm.display.viewTo)
        break;
    }

    cm.display.updateLineNumbers = null;
    if (updated) {
      signalLater(cm, "update", cm);
      if (cm.display.viewFrom != oldFrom || cm.display.viewTo != oldTo)
        signalLater(cm, "viewportChange", cm, cm.display.viewFrom, cm.display.viewTo);
    }
    return updated;
  }

  // Does the actual updating of the line display. Bails out
  // (returning false) when there is nothing to be done and forced is