A few weeks ago, I've mentioned (see Issue
#409) that need for you and you adviced me for take a look at TEMPO ADD-ON... Thanks for that!
But, I also open an ask to JIRA Charting team, since they are responsible for the JIRA ADD-ON that expose workload pie chart gadget.
When they (finally) answered my ask, they recommend me to use timesheet plug-in to address my request. I explained them that you guys (still) don't have pie chart gadgets (please see all the conversation, so far, at: https://answers.atlassian.com/questions/209289/workload-pie-chart-gadget-doesn-t-offer-option-to-choose-worklog-responsible?page=1#214181)
So... I'd like (so much) that you consider to implement this new feature at the future versions of timesheet plug-in.
Hope some response. Thanks again!