On 17/07/2026 13:46, Jon Turney wrote:
On 10/07/2026 15:39, Hamish McIntyre-Bhatty via Cygwin wrote:
Hi all,
Apologies if this has already been reported, but I couldn't find
anything about this exact issue. I've recently found that HiDPI
screens with scaling don't appear to be handled well by Cygwin/X11 -
windows render very small in this configuration. By contrast, if I
use the VcxSrv server with the same Cygwin application it displays at
the size you'd expect.
I'd be happy to send screenshots or logs, or anything else I can send
to help figure out why this is happening. I don't know much about X,
other than that it's hard to maintain, so I appreciate this may not
be an easy problem to fix.
Interesting.
The way this is supposed to work is (i) for windows owned by the X
server, we turn off all the scaling that Windows might do
automatically (so 1 pixel == 1 pixel), and (ii) advise X applications
of the real DPI so they (or, usually, the toolkit they use, qt, gtk,
etc.) can make appropriate scaling decisions.
(Differences with VcxSrv might be because that's not marked dpiAware
and so let's Windows do scaling, or because it has some patches to do
more intelligent things...)
It would be nice to know:
* the DPI of your display
* the dpi reported by xdpyinfo
* the name of an application you see this problem with
Apologies for the very slow reply.
I don't actually know the DPI of my display, as it's a virtual machine
in QEMU/KVM. I'm using the Red Hat QXL display adaptor at 2560x1600,
150% scaling set in Windows.
xdpyinfo reports 144x144 DPI in my Windows VM, which is the same as what
it says on my host OS (LMDE 7).
I see this problem with the wxPython demo, but also any Cygwin
application I've tried that uses the X server. I first noticed it with
my own wxPython-based application, but I sell that so I won't be
providing links to it here.
Best,
Hamish
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