Confusing Cygwin X / xlaunch issue

Jon Turney
Thu Nov 4 14:10:09 GMT 2021

On 26/10/2021 16:38, Eliot Moss wrote:
> On 10/26/2021 4:02 PM, Jon Turney wrote:
>> On 24/10/2021 12:01, Eliot Moss wrote:
>>> First, things work fine when I am using just my hi-res laptop 
>>> display, or that
>>> display plus a hi-res external display in "Extend these displays" mode
>>> according to Windows 10.  At present I am using a lower resolution 
>>> external
>>> display (becaue I am on an extended trip and it's what I have) in 
>>> "Extend
>>> these displays" mode with my hi-res laptop display.  This seems to 
>>> confuse X
>>> (and also xlaunch?).  Here are the issues:
>> Thanks for reporting this problem.
>>> When booted with the external lo-res display as the main display:
>>> - xterm windows come up with a very large font.
>>> - The X menu (controlled by .XWinrc) does not come up.
>> This means that you're right-clicking on the notification area icon, 
>> but no menu appears?
> Correct.
>> If so, I guess this means that we're getting confused about where to 
>> place the menu, but I'm not sure how that could happen.
>> wrt the font scaling issue, looking at the source, it seems that we 
>> don't re-consider the display dpi after a WM_DISPLAYCHANGE message, 
>> but keep on using the value determined at startup.  This is probably a 
>> bug.

I've made an attempt at fixing this in the xserve 21.1.0-1 test release.

The X server should now be aware of Windows DPI changes (only on the 
primary monitor at the moment), and update the X screen information (and 
probably emit some kind of xrandr event, which X applications may take 
note of or not...)

(Advertising this awareness also stops Windows from always reporting to 
it the DPI when it started, and rescaling windows when it changes or 
they move between monitors with different DPI values (which could lead 
to some blurriness))

Perhaps you could try that, and see if it improves things for you?

Jon Turney
Volunteer Cygwin/X X Server maintainer

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