vispy/vispy — pull request #678 by anntzer (2014-12-17 09:10:06+00:00)
Title: Fallback on xrandr to get linux DPI info.

xdpyinfo is not always available on Linux (even with a DE), whereas
xrandr is (AFAICT) at least dependency of KDE and XFCE. But xrandr
fails when used remotely, so keep it too.