Support for HiDPI

[marmarek]

For having full HiDPI support in Qubes, we need:

• have dom0 desktop environment support - upgrade dom0 to Fedora 23 should do - #1807
• have VM applications/toolkits support - Fedora 23 probably is good enough
• somehow inform the VM about the DPI
• possibly improve GUI performance

The last one may be really hard, if turn out to be a problem - because VM have no hardware graphics acceleration, so all that is computed on CPU.

[marmarek]

Regarding informing VM about DPI, the most straightforward (I think) solution would be to pass physical screen size along with its resolution (qubes.SetMonitorLayout qrexec service). But this may pose a big privacy issue, especially for Whonix VMs.
One solution would be to disable this feature for Whonix VMs, but that means no HiDPI support for Whonix. Another idea is to pass some different information - for example some approximate DPI value - like one of 96, 150, 300 and so on.

@adrelanos what would be the best option? Maybe something different?

[marmarek]

Regarding informing VM about DPI, the most straightforward (I think) solution would be to pass physical screen size along with its resolution (qubes.SetMonitorLayout qrexec service). But this may pose a big privacy issue, especially for Whonix VMs.
One solution would be to disable this feature for Whonix VMs, but that means no HiDPI support for Whonix. Another idea is to pass some different information - for example some approximate DPI value - like one of 96, 150, 300 and so on.

@adrelanos what would be the best option? Maybe something different?

[marmarek]

Related message about informing DPI to the VMs: https://groups.google.com/d/msgid/qubes-devel/56E49569.9020506%40noses.com

[marmarek]

Related message about informing DPI to the VMs: https://groups.google.com/d/msgid/qubes-devel/56E49569.9020506%40noses.com

[marmarek]

Status update for Qubes 3.2:

• installer handle HiDPI nicely - enable scaling automatically so it's readable
• KDE5 (dom0) doesn't automatically enable it, but it's a matter of one setting: Increase font dpi (System Settings → Font → Force font dpi, enter a number such as 125, 144 or 150 etc); and if you like, increase icon sizes
• VM - no progress yet. Probably require minor modification of dummyqbs xorg driver (expose an interface to set dPtr->paOutputs[i]->mm_width (and mm_height).

[marmarek]

Status update for Qubes 3.2:

• installer handle HiDPI nicely - enable scaling automatically so it's readable
• KDE5 (dom0) doesn't automatically enable it, but it's a matter of one setting: Increase font dpi (System Settings → Font → Force font dpi, enter a number such as 125, 144 or 150 etc); and if you like, increase icon sizes
• VM - no progress yet. Probably require minor modification of dummyqbs xorg driver (expose an interface to set dPtr->paOutputs[i]->mm_width (and mm_height).

[andrewdavidwong]

On 2016-07-04 14:05, R.B. wrote:

Hello,

For the people who want to use a HIDPI display, or have one on their
laptop, Here's an easy way to get your vm's up to scale while issue
#1951 is open ;-)

Settings that I use on my machine with 3.2rc1:
gsettings set org.gnome.desktop.interface scaling-factor 2
gsettings set org.gnome.desktop.interface text-scaling-factor 0.75

You could run it through qvm-run from dom0 for all your vm's.

Note that for some reason it won't affect templates. The
(gnome-)terminal for instance remains the same size and scale.

For reference: #1951

Enjoy.

Regards,

RB

Original message

[andrewdavidwong]

On 2016-07-04 14:05, R.B. wrote:

Hello,

For the people who want to use a HIDPI display, or have one on their
laptop, Here's an easy way to get your vm's up to scale while issue
#1951 is open ;-)

Settings that I use on my machine with 3.2rc1:
gsettings set org.gnome.desktop.interface scaling-factor 2
gsettings set org.gnome.desktop.interface text-scaling-factor 0.75

You could run it through qvm-run from dom0 for all your vm's.

Note that for some reason it won't affect templates. The
(gnome-)terminal for instance remains the same size and scale.

For reference: #1951

Enjoy.

Regards,

RB

Original message

[brinded]

Awesome! I will readily volunteer my time on any tests regarding HiDPI as I love Qubes and have a 4k laptop (Y50-70). Of note, xrandr pulls up the correct info in regards to resolution (3840x2160) and display size of 344mm x 194mm. However, xdpyinfo returns the same resolution and a display size of 1016mm x 571mm yielding 96dpi. I'm plugging my way through it.

That being said, Fedora 24 with GNome handled it extremely well.

[brinded]

Awesome! I will readily volunteer my time on any tests regarding HiDPI as I love Qubes and have a 4k laptop (Y50-70). Of note, xrandr pulls up the correct info in regards to resolution (3840x2160) and display size of 344mm x 194mm. However, xdpyinfo returns the same resolution and a display size of 1016mm x 571mm yielding 96dpi. I'm plugging my way through it.

That being said, Fedora 24 with GNome handled it extremely well.

[marmarek]

I've added support for custom screen/output size to video driver. It can be even changed on the fly :)
When manually set to HiDPI-suggesting values (DPI > 200), gnome-terminal (and probably other GTK+ applications) in Fedora 23 VM automatically turns on font scaling. According to gnome-settings-daemon sources, it is triggered on:

• DPI >= 192
• height >= 1200px

Those properties expect screen size in mm.

The easiest thing to do would be to pass actual screen size from dom0 directly. But (I guess) this would be major problem for Whonix VMs as physical screen size is even more unique than just resolution. @adrelanos what do you think? I've already proposed some solution in #1951 (comment) - is it ok?

[marmarek]

I've added support for custom screen/output size to video driver. It can be even changed on the fly :)
When manually set to HiDPI-suggesting values (DPI > 200), gnome-terminal (and probably other GTK+ applications) in Fedora 23 VM automatically turns on font scaling. According to gnome-settings-daemon sources, it is triggered on:

• DPI >= 192
• height >= 1200px

Those properties expect screen size in mm.

The easiest thing to do would be to pass actual screen size from dom0 directly. But (I guess) this would be major problem for Whonix VMs as physical screen size is even more unique than just resolution. @adrelanos what do you think? I've already proposed some solution in #1951 (comment) - is it ok?

[adrelanos]

I am not sure yet. Does this require a quick answer?

Another idea is to pass some different information - for example some approximate DPI value - like one of 96, 150, 300 and so on.

This sounds best. The more common the value is, the better.

[adrelanos]

I am not sure yet. Does this require a quick answer?

Another idea is to pass some different information - for example some approximate DPI value - like one of 96, 150, 300 and so on.

This sounds best. The more common the value is, the better.

[andrewdavidwong]

I've marked the first two items as complete since we have F23 in dom0 and an F24 template now.

[andrewdavidwong]

I've marked the first two items as complete since we have F23 in dom0 and an F24 template now.

[najamelan]

This message of the user mailing list might be of interest. I can confirm it works on Q4RC3. After rebooting the template, it's dpi is correct, and it is also propagated to all app vms:

The only way I found to get a reasonable view is to change the default 96 dpi setting of Xft.dpi in /etc/X11/Xresources (in the TemplateVM).

For the whonix-ws template it works when adding it to /etc/X11/Xresources/x11-common

[najamelan]

This message of the user mailing list might be of interest. I can confirm it works on Q4RC3. After rebooting the template, it's dpi is correct, and it is also propagated to all app vms:

The only way I found to get a reasonable view is to change the default 96 dpi setting of Xft.dpi in /etc/X11/Xresources (in the TemplateVM).

For the whonix-ws template it works when adding it to /etc/X11/Xresources/x11-common

[mossy-nw]

setting Xft.dpi to >96 isn't working for me in R4.0_rc4 for debian-9 or fedora-26 templates (whonix not tested).

However, in VMs with fedora-26 templates this solution from R3.2 is working again (running commands in the VM terminal on launch):

gsettings set org.gnome.desktop.interface scaling-factor 2
gsettings set org.gnome.desktop.interface text-scaling-factor 0.75

This fails (with no apparent effect) in VMs with debian-9 templates, with the following error:

dconf-WARNING **: unable to open file '/etc/dconf/db/local': Failed to open file '/etc/dconf/db/local': open() failed: No such file or directory; expect degraded performance

[mossy-nw]

setting Xft.dpi to >96 isn't working for me in R4.0_rc4 for debian-9 or fedora-26 templates (whonix not tested).

However, in VMs with fedora-26 templates this solution from R3.2 is working again (running commands in the VM terminal on launch):

gsettings set org.gnome.desktop.interface scaling-factor 2
gsettings set org.gnome.desktop.interface text-scaling-factor 0.75

This fails (with no apparent effect) in VMs with debian-9 templates, with the following error:

dconf-WARNING **: unable to open file '/etc/dconf/db/local': Failed to open file '/etc/dconf/db/local': open() failed: No such file or directory; expect degraded performance

[mossy-nw]

in R4.0_rc4, for at least one (electron-based) app using a debian-9 template, running the following command in a terminal before launching the app did the trick:

echo Xft.dpi: 144 | xrdb -merge

This also works for torbrowser in a whonix-ws based VM.

[mossy-nw]

in R4.0_rc4, for at least one (electron-based) app using a debian-9 template, running the following command in a terminal before launching the app did the trick:

echo Xft.dpi: 144 | xrdb -merge

This also works for torbrowser in a whonix-ws based VM.

[taradiddles]

just found out that setting DPI scaling depends on the presence of the /usr/libexec/gsd-xsettings daemon (provided by the gnome-settings-daemon package in fedora):

• without /usr/libexec/gsd-xsettings running, applications honor Xft.dpi
• with /usr/libexec/gsd-xsettings running, applications are prevented from using Xft.dpi so the gsettings commands have to used.

I've documented this in https://github.com/Qubes-Community/Contents/blob/master/docs/customization/dpi-scaling.md ; if it gets enough testing (eg. for kde/qt apps) I can submit a PR to the official docs.

[taradiddles]

just found out that setting DPI scaling depends on the presence of the /usr/libexec/gsd-xsettings daemon (provided by the gnome-settings-daemon package in fedora):

• without /usr/libexec/gsd-xsettings running, applications honor Xft.dpi
• with /usr/libexec/gsd-xsettings running, applications are prevented from using Xft.dpi so the gsettings commands have to used.

I've documented this in https://github.com/Qubes-Community/Contents/blob/master/docs/customization/dpi-scaling.md ; if it gets enough testing (eg. for kde/qt apps) I can submit a PR to the official docs.

[ncm]

For the "expect degraded performance" problem, I created
# ln -s /home/user/.config/dconf/user /etc/dconf/db/local
in my debian-9 template. The complaint went away. Dunno about the "degraded performance".

[ncm]

For the "expect degraded performance" problem, I created
# ln -s /home/user/.config/dconf/user /etc/dconf/db/local
in my debian-9 template. The complaint went away. Dunno about the "degraded performance".