Hi, I am trying to draw several unfilled ellipses (ie transparent so you can see all the ellipses although they are partially overlapping). Currently I can draw the ellipses great, but they are not transparent.
I tried to use these directions: root.cern.ch/root/html/TColor.html#C06
But when I run this I get the error: Error: Can’t call TColor::SetAlpha(0.01) in current scope
I googled this error and some documentation at Duke say the GUI backend must be set to qt in order to use this feature (www.phy.duke.edu/~dmb60/the-guide/). But I am running on lxplus5 at CERN, so I don’t see a ~/.rootrc file to edit with these lines to set the qt background.
Is it possible to use this transparency feature?