wicket clickable image with tooltips map

[C.S.]

Dear wicket developers,

i try to integrate wicket with jfreechart. Wicket wiki contains an example
under
https://cwiki.apache.org/confluence/display/WICKET/JFreeChart+with+clickable+imagemap
but this code is 11 yrs old and does not work with current versions.

Speaking of versions: i must stick with jdk 1.8, which means i cannot
upgrade to wicket 9+
Using wicket version 8.12.0

Goal is to create a usemap list to an image, so image is clickable
(contains tooltips).
For image i use a NonCachingImage and for the usemap i use a RefreshingView.

Trouble is, when the RefreshingView renders, the image has no rendering
info yet. So the RefreshingView model is empty. Image creates its rendering
info very late - during onRequest(). RefreshingView is rendered long ago at
this time.

I tried to create the image rendering info before rendering the
RefreshingView.
This is how it works in the old wiki example. Unfortunately, the new
versions throw a StackOverflowException. During Serialization, some
JFreeChart methods interact with some Wicket serialization methods. They
call each other (via reflexion) some 100s of times until StackOverflow
occurs.

What would you suggest? Is there a way to refresh the RefreshingView
without ajax?
Or somehow render the RefreshingView after the image produced its rendering
info?
Or should i use different wicket components? Or wrap/enclose these
components under another component (which one? ).

Thank you for your help

Christos Stieglitz

My code:

HTML:
<img wicket:id="livedata" usemap="#skipper"/>
<map name="skipper">
  <area wicket:id="area"/>
</map>

Java:
RefreshingView<ChartEntity> mapAreas = new RefreshingView<>("area") {
      @Override
      protected Iterator<IModel<ChartEntity>> getItemModels() {
        ...
        // This is called during onRender(). List model is empty
        return models.iterator();
      }

      @Override
      protected void populateItem(Item<ChartEntity> item) {
        ChartEntity entity = item.getModelObject();
        item.add(new AttributeAppender("shape", entity.getShapeType()));
        item.add(new AttributeAppender("coords", entity.getShapeCoords()));
        item.add(new AttributeAppender("href", "#"));
        item.add(new TooltipBehavior(entity.getToolTipText()));
      }
    };
mapAreas.setOutputMarkupId(Boolean.TRUE);
add(mapAreas);

NonCachingImage ch = new NonCachingImage("livedata", Model.of(chart)) {
      @Override
      protected DynamicImageResource getImageResource() {
        return new DynamicImageResource() {
          @Override
          protected byte[] getImageData(IResource.Attributes attributes) {
            ChartRenderingInfo renderingInfo = new ChartRenderingInfo();
            // chart is a JFreeChart
            BufferedImage imgbytes = chart.createBufferedImage(imgwidth,
imgheight, renderingInfo);

            EntityCollection entities = renderingInfo.getEntityCollection();
            // This is called very late, during onRequest().
            // EntityCollection contains now everything is needed,
            // but how to call
            // RefreshingView.onRender() from here?
            // If i put this code anywhere else i get
StackOverflowException.
            return toImageData(imgbytes);
          }
        };
      }
    };
    add(ch);