Any suggestion on charting plugin for time tracking?
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I've been spending quite some time looking for a charting plugin for time tracking, ie. Engine Time Tracking chart as following image:
![enter image description here][1] 

A bit explanation: 

*green / red / gray* denotes *engine on / engine off / not available*
*horizontal axis* is the *time line for each day*
*vertical axis* is *every single day*

I am just showing an example and expecting someone here has any idea about this kind of charting plugins. I am not sure whether [HighCharts stacked bar chart][2] can do that, since I want a status switching bar chart, not an accumulative one. 

Thanks in advance. 


  [1]: http://i.stack.imgur.com/YoTSd.png
  [2]: http://www.highcharts.com/demo/bar-stacked