[vtkusers] HiDPI not working on VTK 7.1.0 rc2

[Michael Jackson]

I just tried the HiDPI support on VTK 7.1.0-rc2 and I get the usual VTK 
rendering canvas that is half the size of the widget that it is embedded 
into.

We are using Qt 5.6.2 on macOS 10.10.5. I compiled my original pull 
request (way back in Aug 2016) and that patch gives me a full size 
canvas. But when compiling the latest VTK 7.1.0-rc2 I get the half size 
canvas. I thought the branch was merged on Sept 28 2016 but I guess I 
got busy and never actually tested it on a retina screen.

Most likely I am doing something wrong in the initialization in my code 
but just in case can anyone else confirm with Qt 5.6.x that they can 
actually get a Retina/HiDPI canvas?

Thanks

-- 
Michael A. Jackson
BlueQuartz Software, LLC
[e]: mike.jackson at bluequartz.net