Cygwin/X with Win10 display scaling corrupting font display of typed characters - Issue identified

[Jon Turney]

On 19/01/2022 00:02, Ken Whitesell wrote:
> On 1/17/2022 1:29 PM, Ken Whitesell wrote:
>>
>> Is there a known solution for this? (Or is it known that there is no 
>> solution?)

Thanks for reporting this.

>> Any guidance, pointers, suggestions of avenues for further research, 
>> or other information, will all be greatly appreciated.
>>
> After more research and experimentation, it appears to be related to one 
> of xorg-server, xorg-server-common, or xorg-server-xorg.
> 
> Installing the older version 1.20.12-1 of these packages allows the 
> windows to be moved between monitors without any issues. Upgrading to 
> the current version 21.1.3-1 creates the problems. I'm able to replicate 
> this behavior on two different laptops with two different external 
> monitors.

It seems likely that this is an unintended effect of changes in 
xorg-server 21.1.0-1, trying to fix problems in this area (See [1])

You might find that starting the server and specifying a fixed dpi value 
with the '-dpi' option might workaround this.

[1] https://cygwin.com/pipermail/cygwin-announce/2021-November/010286.html

> If I change the scaling from 125% to 100% on the laptop's display,
> the problem appears until I restart Cygwin/X. Restarting Cygwin/X
> shows it displaying properly, until I change the scaling again.

I could only reproduce this problem with mis-rendering when changing the 
scaling on the secondary monitor.

(This is presumably somehow related to the fact that we now keep that 
window at the same pixel dimensions, rather than allowing Windows to 
scale it).