[QGIS-Developer] Development / HiDPI / Linux

[Matthias Kuhn]

Hi developers,

Just for a couple of days I'm a happy owner of a HiDPI device on which I
immediately setup Fedora 27 which ships with Gnome 3.26, wayland, Qt 5.9
and all the other nice new libraries and stuff.

Trying to develop (and use the system otherwise) I failed terribly to
get a satisfactory configuration for QGIS development (and also
otherwise). There are a few knobs to "finetune" DPI, but I just seem not
to be able to get things right. Each variable I set somewhere has
side-effects somewhere else.

* Gnome itself already has a scale setting which at 100% makes things
very, very tiny and at 200% (the only other option) makes everything
grandma mode.

* Then there is also the environment variable
QT_AUTO_SCREEN_SCALE_FACTOR which seems to make Qt Creator a bit more
usable. (Qt Creator internally actually seems to be using two different
dpi's - probably QML vs. QWidget issues) But with this env variable set,
the QGIS interface seems to be scaled up twice.

* Then there are various other variables for Thunderbird, Firefox, ...
that again allow to scale contents for specific applications

* And I read somewhere about xrandr for additional zooming, but I'm
neither convinced that this is a good approach since some mouse setting
apparently needs to compensate for this, nor does this seem to have any
effect (probably because of Wayland) Source:
https://wiki.archlinux.org/index.php/HiDPI


So apart from a rant for the mess by GUI frameworks and window managers,
there's also a question: did anyone succeed to set things up properly?


Thanks

Matthias