webbrowser-app does not honour scale setting on HiDPI display

[Rachel Greenham]

The attached screenshot should say it all, showing it in comparison with Firefox and, indeed, the rest of the Unity desktop.

Basically, on a 4K display, with a native resolution of 3840x2160, but with the scaling factor set to 2, and Scale all window contents set on, *most* of the unity desktop these days respects this; it nearly all works.

webbrowser-app seems to have no awareness of it at all, and thus its windows show up tiny.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: webbrowser-app 0.23+16.04.20160413-0ubuntu1
ProcVersionSignature: Ubuntu 4.4.0-22.40-generic 4.4.8
Uname: Linux 4.4.0-22-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
CurrentDesktop: Unity
Date: Fri Jun 10 12:55:30 2016
InstallationDate: Installed on 2016-03-30 (71 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Beta amd64 (20160323)
SourcePackage: webbrowser-app
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Chris Coulson (chrisccoulson)]

This isn't really a webbrowser-app or Oxide issue - this is a desktop environment issue. If you run webbrowser-app with QT_DEVICE_PIXEL_RATIO=2 then it works fine.

[Rachel Greenham (rachel-strangenoises)]

confirmed that environment variable set before opening the app works. Whose project do we complain at that QT apps don't (or rather, only inconsistently) follow this setting?

(For instance, when I set that in my ~/.profile, a different QT5 app, in which originally *some* of its widgets are scaled correctly, and some tiny, now has those former ones twice as big and the others normal-size.)

FWIW I put this in my ~/.profile:

QT_DEVICE_PIXEL_RATIO=$(gsettings get org.gnome.desktop.interface scaling-factor | cut -f2 -d' ')
export QT_DEVICE_PIXEL_RATIO

Obviously not ideal though. And I'm not even sure that's the correct setting, seeing as it's an integer value, and shows an int even when scaling factor in the display prefs is set to a fractional value.

But it fixes it for now so I can use webapp-container for TweetDeck, and that's where I came in. ;-)

[Olivier Tilloy (osomon)]

Tentatively re-targetting at unity-control-center. Presumably, the control center should also set the value of QT_DEVICE_PIXEL_RATIO. Although this wouldn’t help ensure that it remains in sync with the value of the dconf key at all times.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.