This functionality is only available in the jbpm console application but you could recreate similar in your own app. What console does is gets the process image (from Guvnor or classpath, where it can find it), queries the engine for currently active nodes, checks the bpmn2 for their positioning (in the BPMNDiagram section of your process bpmn2) and overlays a div ontop of the image which shows the red arrow markers next to the tasks that are currnetly active.

Hope this helps.

Can you explain where it makes the process of overlays in the jbpm console?

Have a look at this. Might be helpful.

http://community.jboss.org/people/roxy1987/blog/2011/09/13/image-diagram-functionality-in-custom-web-application-jbpm-4

regards.

Hi, sorry for late response, here is the code of the console which overlays the play_red_big.png in a div next to active nodes of the process image:

https://github.com/bpmc/bpm-console/blob/master/gui/war/src/main/java/org/jboss/bpm/console/client/process/ActivityDiagramView.java

Hope this helps.