Bug 1023667

Summary:	HiDPI display with Firefox-gtk3 under KDE
Product:	[openSUSE] openSUSE Tumbleweed	Reporter:	Ulrich Derenthal <uli.2001>
Component:	Firefox	Assignee:	E-mail List <bnc-team-mozilla>
Status:	RESOLVED FIXED	QA Contact:	E-mail List <qa-bugs>
Severity:	Normal
Priority:	P5 - None	CC:	badshah400, uli.2001, wolfgang
Version:	Current
Target Milestone:	---
Hardware:	Other
OS:	Other
Whiteboard:	gtk3
Found By:	---	Services Priority:
Business Priority:		Blocker:	---
Marketing QA Status:	---	IT Deployment:	---
Bug Depends on:
Bug Blocks:	977710

Description Ulrich Derenthal 2017-02-06 07:05:22 UTC

I am using Opensuse Tumbleweed on my Thinkpad T460s witha 14 inch high-resolution screen (2560 x 1440 Pixel, WQHD).

To have a reasonable size for fonts and control elements, I added the line

ServerArguments=-nolisten tcp -dpi 144

in the [XDisplay] section of /etc/sddm.conf

This works perfectly in KDE and also with GTK applications under KDE such as unison, and until yesterday, it also worked in Firefox.

But after running "zypper up" and restarting firefox (and also the whole system later), the icons, menus and webpages in Firefox are too small. I have no idea whether this new behavior is due to changes in Firefox or GTK (or elsewhere). My Firefox version is:

> rpm -q MozillaFirefox
MozillaFirefox-51.0.1-1.2.x86_64

On

https://wiki.archlinux.org/index.php/HiDPI

I found the option to do "export GDK_SCALE=2" before starting Firefox. This works, but makes Firefox too big for my purposes (and apparently only integer scaling factors are allowed).

Comment 1 Ulrich Derenthal 2017-02-06 07:56:26 UTC

I just noticed another change in the behavior of Firefox (most likely also since the last update):

When I left-click somewhere on the scrollbar outside the slider, Firefox was previous scrolling one "page" (as if I had pressed the page-up and page-down key) in this direction.

Now it jumps directly to the corresponding position of the webpage (bottom of the webpage if I click close to the lower end of the scrollbar; middle of the page if I click on the middle of the scrollbar, and so on).

Comment 2 Wolfgang Rosenauer 2017-02-06 20:02:19 UTC

The DPI situation is also reported in bug 1022830. Please have a look there.

Comment 3 Wolfgang Rosenauer 2017-02-06 20:07:56 UTC

BTW, what is extremely interesting to us is if this is a plain Firefox issue or related to the openSUSE packages only.
Do you have the chance to try an upstream tarball of the same version and compare it?

Comment 4 Ulrich Derenthal 2017-02-07 11:48:44 UTC

I downloaded firefox-51.0.1.tar.bz2 from https://www.mozilla.org/de/firefox/new/ and unpacked and ran it, and the behavior is the same.

As described in the other bug report, I also noticed now that the mouse cursor is slightly different in Firefox than in KDE applications.

Comment 5 Atri Bhattacharya 2018-04-01 22:09:36 UTC

Is this fixed now? We got a patch included for gtk3 that veers from upstream and actually provides this dpi compatibility, but a confirmation of whether this is fixed will really help. Thanks!

Comment 6 Ulrich Derenthal 2018-04-03 09:01:10 UTC

The sizes are fixed.

The scrollbars still behave differently in Firefox than in KDE applications.

Comment 7 Atri Bhattacharya 2018-04-03 09:52:41 UTC

The scrollbar behaviour is intentional. Unless this differs on openSUSE compared to the upstream tarball, it may be useful to open a bug upstream (https://bugzilla.mozilla.org/) for that. In any case, the summary of this bug refers to font scaling on HiDPI displays, and not the scrollbar behaviour. Let's close this as fixed.