X colormap problem when viewed via Microsoft Remote Desktop

X colormap problem when viewed via Microsoft Remote Desktop

[jeff_schenck]

After a fairly recent update of cygwin, I now find that all my X
windows (xterm, emacs, etc.) have color and font problems.  Non-x
terminal windows are fine.  Windows 7 is running as a VM on an esxi
hypervisor, so I view it remotely with Microsoft Remote Desktop.  It
worked well on a previous cygwin release, but I don't have the exact
date when it changed.  Also, I don't think the problem is with MRD
because I see it with VNC also.

I tried attaching cygcheck.out and XWin.0.log but the mail bounced
with the message "552 spam score exceeded threshold".

Thanks,
Jeff Schenck

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Re: X colormap problem when viewed via Microsoft Remote Desktop

[Jon Turney]

On 29/01/2017 03:16, jeff_schenck@att.net wrote:
> After a fairly recent update of cygwin, I now find that all my X
> windows (xterm, emacs, etc.) have color and font problems.  Non-x
> terminal windows are fine.  Windows 7 is running as a VM on an esxi
> hypervisor, so I view it remotely with Microsoft Remote Desktop.  It
> worked well on a previous cygwin release, but I don't have the exact
> date when it changed.  Also, I don't think the problem is with MRD
> because I see it with VNC also.

Thanks for reporting this problem.

"color and font problems" is a bit vague.  Can you upload a screenshot 
somewhere which illustrates this?

This is unlikely to be a problem with actual X colourmaps unless you are 
using antique X clients which use 8 bit visuals.

However, RDP can step down the display colour depth, whereas the colour 
depth of an X server root window cannot change, which can cause 
dithering to occur.

Additionally, sometimes DirectDraw rendering to RDP doesn't seem to work 
properly, for unknown reasons. (This is discussed briefly in [1])

Since this has started 'recently', I guess it might be related to the 
'-compositewm' option being turned on by default [2].

So, you might try starting the X server with a limited colour depth 
(e.g. '-depth 16'), or try the '-engine 1' or '-nocompositewm' options [3].

[1] https://x.cygwin.com/docs/ug/using-terminal-server.html
[2] https://cygwin.com/ml/cygwin-announce/2016-06/msg00045.html
[3] https://x.cygwin.com/docs/faq/cygwin-x-faq.html#q-command-line-args

-- 
Jon Turney
Volunteer Cygwin/X X Server maintainer

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Re: X colormap problem when viewed via Microsoft Remote Desktop

[jeff_schenck]

Jon, thanks for your suggestion.  Using the -nocompositewm option
fixed my problem.  If you'd still like a screenshot, I can send one if
the mailing list doesn't mind big attachments.  Basically, it looks
like the color map is wrong.  My terminal window background is
brownish-green instead of dark grey and font edges are fuzzy and
multicolored.  A plot window I created has incorrect colors but the
plot is legible.

Thanks!
Jeff

----- On Mon, Jan 30, 2017 at 05:54:07AM PST, Jon Turney wrote:

>On 29/01/2017 03:16, jeff_schenck@att.net wrote:
>>After a fairly recent update of cygwin, I now find that all my X
>>windows (xterm, emacs, etc.) have color and font problems.  Non-x
>>terminal windows are fine.  Windows 7 is running as a VM on an esxi
>>hypervisor, so I view it remotely with Microsoft Remote Desktop.  It
>>worked well on a previous cygwin release, but I don't have the exact
>>date when it changed.  Also, I don't think the problem is with MRD
>>because I see it with VNC also.
>
>Thanks for reporting this problem.
>
>"color and font problems" is a bit vague.  Can you upload a screenshot 
>somewhere which illustrates this?
>
>This is unlikely to be a problem with actual X colourmaps unless you 
>are using antique X clients which use 8 bit visuals.
>
>However, RDP can step down the display colour depth, whereas the 
>colour depth of an X server root window cannot change, which can cause 
>dithering to occur.
>
>Additionally, sometimes DirectDraw rendering to RDP doesn't seem to 
>work properly, for unknown reasons. (This is discussed briefly in [1])
>
>Since this has started 'recently', I guess it might be related to the 
>'-compositewm' option being turned on by default [2].
>
>So, you might try starting the X server with a limited colour depth 
>(e.g. '-depth 16'), or try the '-engine 1' or '-nocompositewm' options 
>[3].
>
>[1] https://x.cygwin.com/docs/ug/using-terminal-server.html
>[2] https://cygwin.com/ml/cygwin-announce/2016-06/msg00045.html
>[3] https://x.cygwin.com/docs/faq/cygwin-x-faq.html#q-command-line-args
>
>-- 
>Jon Turney
>Volunteer Cygwin/X X Server maintainer
>

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Re: X colormap problem when viewed via Microsoft Remote Desktop

[Csaba Raduly]

Hi Jeff,

On Wed, Feb 1, 2017 at 6:22 AM,  <jeff_schenck@att.net> wrote:
> Jon, thanks for your suggestion.  Using the -nocompositewm option
> fixed my problem.  If you'd still like a screenshot, I can send one if
> the mailing list doesn't mind big attachments.

Instead of sending the screenshot to the mailing list, I'd suggest you
upload the picture to e.g. imgur and send the link instead.

Csaba
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