Chromium launch script should follow ubuntu Scaling setting to work on HiDPI screens

[Marco Trevisan (Treviño)]

Chromium supports the --force-device-scale-factor=X.Y parameter, and it should be used in the chromium launch script in order to respect the unity scaling settings.

So when $XDG_CURRENT_DESKTOP is Unity, chromium should read these gsettings keys:
  com.ubuntu.user-interface scale-factor
  com.canonical.Unity.Interface app-scale-factor-monitor
  com.canonical.Unity.Interface app-fallback-to-maximum-scale-factor

And using these valuse to compute the proper X.Y scale parameter to be used for defining a force-device-scale-factor (if the user has not provided another one).

The logic that should be implemented must match what's done in UnitySettings [1].

[1] http://bazaar.launchpad.net/~unity-team/unity/trunk/view/head:/unity-shared/UnitySettings.cpp#L242

[Dan Poler (l-dan)]

It's annoying that Chromium does not yet Do The Right Thing with regard to scaling on Linux. However, the --force-device-scaling-factor=X.Y where X.Y > 1.0 breaks things in some interesting ways. Menus appear in the wrong place and are in some cases unusable, and desktop notifications stop functioning. However, I'd be hard-pressed to say that we should decide as a default behavior to break these functions - versus having it squinty but fully functional.

[Marco Trevisan (Treviño) (3v1n0)]

True, about the menu issue, it doesn't seem a big deal (I'm not confident with the chromium code, but it just seems all we should do is multiply the popup offset with the scale value), the notification one could just be the same offset problem?

Also, In general I think it's better to provide a visible (also if slightly broken view), than unusable one :)

[Marco Trevisan (Treviño) (3v1n0)]

I've reported the issue regarding menus and popups at https://code.google.com/p/chromium/issues/detail?id=370883

[Kai Mast (kai-mast)]

Still present in ubuntu wily :(