(mgp-users 00024) A little bit of advice needed...

[Luigi Rizzo <luigi@labinfo.iet.unipi.it>]

Hi,

i need a little bit of advice on mgp internals.
I have a student here who is working on mgp with the following goals:

  #1 make a Windows port;
	this will make much easier to distribute mgp
	presentations.

  #2 build a multicast-enabled version of mgp.

	in this way i plan to use mgp in much the same way as
	other videoconferencing tools.

#1 is (relatively) trivial i hope, by either emulating the subset of
X11 functions used by mgp, or by rewriting higher level functions
used to draw the various objects and manage the screen.
My feeling is that the second approach is easier, provided one knows
what needs to be rewritten. Could you give us a few suggestions about
this.

For #2, the idea is roughly the following: one builds a tarball
containing all the files (source or pre-rendered slides) needed
for a presentation, distributes it using a bulk transfer protocol
such as our RMDP (see http://www.iet.unipi.it/~luigi/research.html),
then uses an RTP stream to send commands to the remote listeners.

The main modifications needed to mgp for this task are:
 1) being able to process input from both the keyboard _and_
    another file descriptor.
    This mechanism (assuming it is not already in place) can be useful
    to make a presentation controlled by external processes. E.g. i
    could record the audio related to a presentation, annotate the
    audio track, and let the audio player send commands to mgp.

 2) optionally, being able to access pre-rendered objects rather
    than source. This mechanism could be even useful to support
    background rendering of slides. (I know there are limitations
    with animations, live windows, etc.)

Again, a little bit of advice on the better approach to do the
above will be appreciated.

I suppose there is no documentation on the mgp data structures, so in
the process we might as well end up writing some documentation on the
internal representation format and code structure, in the hope it can
be useful to others.

	thanks
	luigi
-----------------------------+--------------------------------------
Luigi Rizzo                  |  Dip. di Ingegneria dell'Informazione
email: luigi@iet.unipi.it    |  Universita' di Pisa
tel: +39-50-568533           |  via Diotisalvi 2, 56126 PISA (Italy)
fax: +39-50-568522           |  http://www.iet.unipi.it/~luigi/
_____________________________|______________________________________