Question about vnc server/viewer in 16bit mode

[Jonathan Morton]

>The last few days I have been experimenting with running
>the Xvnc server (on a Sparc Solaris) and connecting with
>a viewer running on a Pentium Linux box.
>
>I have trouble getting the colors to come out right. The
>only way I can get the colors to be right is if I run the
>Xvnc server in 8bit PseudoColor mode and run my Linux
>Xserver with a default visual of 8bit PseudoColor. In this
>scenario, all the colors come out correctly. However, I'd
>like to run the Xvnc server in 16bit truecolor mode because
>I normally run my Linux Xserver with 16bit truecolor as the
>default visual. However, I get completely messed up colors.
>
>I have tried using the -depth  and -pixelformat options for
>the Xvnc server to try and match up the mapping of the red
>green, and blue bits, but no matter what I do, the colors
>are messed up.
>
>Is there a general known problem with 16bit truecolor mode
>for vnc on X?

Yes, I understand there is a known problem with the X viewer in both 16-bit
and 24-bit modes.  This seems to show up most when a 'raw' encoded
rectangle is sent from the server, whether as part of a hextile stream or
as normal.  I myself have observed the problem when using the X viewer via
a Solaris box, viewed on my Macintosh's X server (MI/X).  It is not a
problem with the X or any other server - it shows up on my Macintosh
server, which is viewed correctly by both Macintosh and Wintel viewers.

>Interestingly enough, when I run the NT viewer (viewing
>the Xvnc server) the colors come out perfect. This seems
>to indicate that the problem might be in the X vnc viewer.
>
>Help will be greatly appreciated.

Try running in Hextile mode, which should minimise the number of Raw
packets sent - these are the ones that seem to get mangled.

>Thanks
>
>Freddy

Footnote: if anyone wants to fix that bug, I have a further suggestion.
Instead of painting X rectangles for every Hextile element, why not build
up a 16x16 pixmap at a time and send that?  I think it would be much faster
for most low-end X terminals, and more efficient of bandwidth too.  Just a
thought...

--------------------------------------------------------------
from:     Jonathan "Chromatix" Morton
mail:     chromi "at" cyberspace.org  (not for attachments)
uni-mail: j.d.morton "at" lancaster.ac.uk



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