What is the output of `gtk-query-settings |grep gtk-xft-dpi`? Is GDK_SCALE set in your environment?

gtk-xft-dpi: 196608

GDK_SCALE is not set.

That's strange, from I read if GDK_SCALE is unset gtk-xft-dpi should be 98304 (96 dpi) independently on the actual pixel density. Let me also make sure your output of `gsettings get org.gnome.desktop.interface scaling-factor` and are you on X11 or Wayland?

In fact, could you compile this program and run it?

gcc `pkg-config --cflags gtk+-3.0` gtk-print-scale-factor.c -o gtk-print-scale-factor `pkg-config --libs gtk+-3.0`

I'm on X11, XFCE4 with AwesomeWM.

I guess this is not very useful outside GNOME?
$ gsettings get org.gnome.desktop.interface scaling-factor
uint32 0

And your gtk-print-scale-factor:
Scale factor: 1

Tried the above command in "GNOME on Xorg":

$ gsettings get org.gnome.desktop.interface scaling-factor
uint32 0

gtk-print-scale-factor:
Scale factor: 2

And electron correctly scales itself in GNOME.

So I guess it starts to depend on GTK scale factor instead of X dpi settings?

Thank you for your feedback, I'll work on a fix as soon as I can. BTW, do other gtk3 applications scale correctly in your environment? Can you try something like evince or gnome-terminal?

Will do, but I'm afraid that'll be 5 days later.

For now I can only recall that some GTK3 applications (Nemo file manager at least) do not scale at all because of no GDK_SCALE set outside GNOME, but Chromium (and Slack, aur/slack-desktop, which is using a prebuilt electron) scales correctly.

I too have this issue, running atom from a KDE environment. My display is 3840x2160 and the scale factor is set to 2 in the KDE display settings. The font dpi is set to 192 in the KDE settings.

Running the commands gives:
gsettings get org.gnome.desktop.interface scaling-factor:
uint32 0

gtk-print-scale-factor:
Scale factor: 1

From the KDE environment, firefox scales fine. However, I installed gnome-terminal, nautilus and gedit and they do not scale. (gnome-terminal was deceptive because the console font seemed fine, but the menus were not)
When I unset the font dpi (to 96) firefox did not scale and nautilus and gnome-terminal, at least, were even smaller.

Found a workaround, run it with:

export GDK_SCALE=2 && atom

The same thing does not work with nautilus, gedit or gnome-terminal, with the result either being what appear to be no scaling or 4x scaling. It seems to me that this is a wider problem with the scaling of GTK3 apps outside of gnome.

*edit: you have to unset the font DPI or you will get 4x scaling

@trigtriarius: or set GDK_DPI_SCALE=0.5 too. But this causes more problem.

@tensor5: just confirmed that GTK3 apps' UI elements does not scale if only X dpi and Xft dpi are set, only text scales.

For the people not using GNOME: have you tried

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

?

No effect on Electron or GTK3 apps.

Any update on this? The HiDPI support is still broken in electron 1.4.4-1 outside GNOME.

I could revert it to the state of 1.4.1-1, but this is a bug affecting all GTK3 apps running outside GNOME, so in my opinion we should open a new bug for that.

For other GTK3 apps and Chromium (GTK2), the text size changes according to Xft.dpi. For electron that value is useless.

In this case I guess electron should behave like Chromium?

@hexchain, can you try electron 1.4.8-2?

I can confirm that it respects the DPI set in plasma's system settings now (which is probably Xft.dpi, but I can't be bothered checking).

Broken again in 1.4.12-1

Hi there, so this is probably the issue I’m facing with Riot (Matrix webapp client, using electron). I can’t get it to work correctly with HiDPI, while all others applications on my system behave well.

I’m using the --dpi arg of X to start it at a 192 DPI resolution, and have GDK_SCALE=2 in my profile.

I was advised we can pass “--force-device-scale-factor=2” to electron apps as a workaround. But a fix would be better.

That being said, maybe this would be solved by updating to latest electron, current release in Arch is very old.

I'll look into it more deeply once I complete the upgrade to Electron 1.6.

I don't have this problem anymore, with 1.4.16-2.

~> xrdb -query | grep Xft.dpi
Xft.dpi: 192
~> xdpyinfo | grep -B2 resolution
screen #0:
dimensions: 3200x1800 pixels (847x476 millimeters)
resolution: 96x96 dots per inch

And there are no $GDK_* set.

Is it working for you with the latest electron 1.7.11-1 release?

Does not work for me. Still have to pass “--force-device-scale-factor=2” as arg.

Do we really need this patch? What happens if you rebuild the package without it?
https://git.archlinux.org/svntogit/community.git/tree/trunk/chromium-gtk3.patch?h=packages/electron

It works for me. I'm using XFCE on Xorg.

~ $ xrdb -query | grep Xft.dpi
Xft.dpi: 192
~ $ xdpyinfo | grep -B2 resolution
screen #0:
dimensions: 3200x1800 pixels (846x476 millimeters)
resolution: 96x96 dots per inch

No $GDK_* environment variables set.

It still works if I set GDK_SCALE=2 GDK_DPI_SCALE=0.5 .