nanogui: Thread: VNC viewer for nano-X

It looks like I am not going to have any time to work on Microwindows
for the next couple of weeks so I am making my current VNC sources
available for anyone else who wants to have a play. You can find them
at:

http://dspace.dial.pipex.com/town/way/fr30/uclinux/downloads/nx_vnc332.tar.gz

The README follows below.

Please note that this is work in progress, it runs on my test platform
but there is still a lot to do, see the README for more details.

If anyone gets it running on a different platform, I'd be interested
in hearing how fast/slow it feels. It is very slow on my Isicad Prisma
but I'm fairly sure that is a problem with the Prisma's graphics and
not with nano-X.

Regards,

George Harvey
####@####.####

===== begin README =====

               README for the nano-X VNC viewer

What is VNC ?
-------------
VNC is Virtual Network Computing, you have a 'viewer' running on one
machine which allows you to control the desktop of a different
machine via the VNC 'server'. The design allows the viewer and server
to run on different hardware and different operating systems yet
still work together. What this means in practice is that you can have
a Windoze desktop in a window on your X display or vice-versa.
The viewer has also been designed to be small and portable so it
seemed like a good candidate for a nano-X application.

More info, source and binaries can be found at:

    http://www.uk.research.att.com/vnc/


Status of the nano-X port
-------------------------
The nano-X port is based on the VNC viewer for X, version 3.2.2.
This is a work-in-progress release, I have only tested it on one
platform and there are still some important areas of functionality
missing. This is where I am up to:

+ Compiled with Microwindows version 0.88pre4
+ Viewer tested on uClinux running on an Isicad Prisma 700
  workstation with the serial mouse driver, the tty keyboard driver
  and my own screen driver. The Prisma has a 1280 x 1024, 256 colour
  display but it is not accessible as a frame buffer so needs a 
  custom microwindows screen driver.
+ Tested with VNC servers running on NetBSD-Amiga and Slackware
  Linux.
+ Only tested with an 8-bit palette display. Palette handling is a
  problem area since VNC wants to set the viewer's palette to match
  the server but nano-X does not allow applications to have their
  own palette.
+ Only tested with the client code linked directly into the nano-X
  server.
+ Keyboard handling is working but only for simple ASCII text, no
  shift-clicking.
+ Mouse seems to work OK.
+ No way to scroll the screen if the viewer window is smaller than 
  the server's screen.
+ No way to exit from the viewer, you need to kill the process.
+ Still some bugs with screen updating.
+ Will output some debugging messages on stdout.
+ Runs very slowly on the Prisma, most likely due to the Prisma's
  weird graphics interface.

GsSelect() problem
------------------
I use the GrMainLoop() function, with a callback, for the central
event loop. I found that GsSelect() gets called twice, once in
GrGetNextEvent() and then immediately after in GrCheckNextEvent().
This seemed to cause mouse and keyboard handling to fail after a
short while. My temporary fix is to comment out the call in
GrCheckNextevent().

Installation
------------
The tarball is intended to be unpacked in the src/demos subdirectory
of the Microwindows distribution. The makefiles have been adapted
from those used by the rest of the demo programs so it should build
from the top level 'make'. The resulting binary will appear as
src/bin/vnc. You will need a network connection to a VNC server
to do anything with it :-)


George Harvey
####@####.####
4th April 2000

==== end README ====

:                README for the nano-X VNC viewer

Very very cool.  I've got a friend who uses VNC alot,
I've asked him to check this out.  I'll take a look at
the work also.

I've commented on a couple things below:


: + Only tested with an 8-bit palette display. Palette handling is a
:   problem area since VNC wants to set the viewer's palette to match
:   the server but nano-X does not allow applications to have their
:   own palette.

Setting any portion of the hardware palette is easy:  I'll add
GrSetPalette to my list, and by the time you're back, it should
be done.


: + No way to exit from the viewer, you need to kill the process.

You must be running with the new -e option that tells nano-x
not to exit on ESC.  Perhaps we need a programmable exit 
sequence or character.

: ------------------
: I use the GrMainLoop() function, with a callback, for the central
: event loop. I found that GsSelect() gets called twice, once in
: GrGetNextEvent() and then immediately after in GrCheckNextEvent().
: This seemed to cause mouse and keyboard handling to fail after a
: short while. My temporary fix is to comment out the call in
: GrCheckNextevent().

I'm still waiting for some more input from Morten on this,
but I'll check it out also.


Regards,

Greg

On 05-Apr-00, Greg Haerr wrote:
>:                README for the nano-X VNC viewer

[ snip ]

>: + Only tested with an 8-bit palette display. Palette handling is a
>:   problem area since VNC wants to set the viewer's palette to match
>:   the server but nano-X does not allow applications to have their
>:   own palette.

>Setting any portion of the hardware palette is easy:  I'll add
>GrSetPalette to my list, and by the time you're back, it should
>be done.

Great!

>: + No way to exit from the viewer, you need to kill the process.

>You must be running with the new -e option that tells nano-x
>not to exit on ESC.  Perhaps we need a programmable exit 
>sequence or character.

Hmm, I never tried ESC. If it is built in to the keyboard handler
then it should work. I knew the demo programs exited on ESC but I
thought it was something in the demo code rather than in nano-X
itself.

[ snip ]


Regards,

George Harvey