Unifying the approach to histogram visualisation in ATLAS the Online Histogram Presenter

The challenging experimental environment and the extreme complexity of modern high-energy physics experiments make online monitoring an essential tool to assess the quality of the acquired data. Among the tools at shifters and experts disposal to asses the status of the hardware and the quality of data, plots play a special role, as they can summarise a large amount information in a graphical presentation. Updated regularly, they probe the evolution of monitored quantities. Ideally, a dedicated graphical presenter should not only show these plots, but also refresh them automatically each time they are updated on the server, providing the user with the latest available information. This is precisely the assignment of the Online Histogram Presenter, which is developed within the ATLAS collaboration and is described in this paper.