Date   : Fri, 04 Oct 1991 11:09:05 GMT
From   : snorkelwacker.mit.edu!hri.com!spool.mu.edu!munnari.oz.au!metro!ipso!dave@bloom-beacon.mit.edu (Dave Horsfall)
Subject: Graphics standard for small systems?

Has anyone defined a suitable (portable?) graphics standard for small
machines?  Things like Sun raster file, X, GIF etc are all very well,
but a little bit overboard for what I want.  I'm sure that many CP/M
machines have graphics support, but I'll bet they all have their own
standard, possibly even depending on the graphics package they run at
the time.  Is there a suitable portable format, amenable to conversion
between other formats?

For example, the system here is a Microbee (if you've never heard of
it, don't worry, if you have you'll know what I mean) that has a character
addressable screen (80 x 24/25), but you get to define the characters in
a cell of 9 x 11 (I think) dots, thus permitting arbitrary graphics, as
long as your character map doesn't overflow (128 user-defined cells).
For all I know, other systems are dot-addressable etc.

What I'm looking for is a format that handles most hardware oddities,
but can run under CP/M without requiring whopping large arrays etc.
I guess I'll define my own, but I prefer to use an existing one.

Something else that occurred to me while I was typing this was some sort
of a protocol - a heavily cut-down "X" perhaps - that could be put into
terminal emulators running remote graphics packages.  E.g. you want to
display your favourite GIF file, stored on your works machine, on your
colour CP/M computer.  You would therefore run a viewer that translates
the GIF format into this protocol, and your terminal emulator would then
start hammering away on the colour maps etc.  Anyone done this?

[ Note for Microbee owners - TELCOM is all very well, but terribly limited
  in its capabilities.  What it really needs is a DECENT VT-100 emulator,
  a better way of implementing "chat" scripts, a "macro" capability, and the
  ability to run a program on the capture buffer, possibly leaving the
  results there for subsequent transmission.  An in-core editor would also
  be nice.  Am I asking too much? :-)  I'll see what I can write. ]

[ Note for non-Microbee owners - before you leap up and say "Why don't you
  run XYZ-TERM or something?  It has all that and more besides!" consider
  that the Microbee does NOT have a serial port - instead it bit-bangs
  on a Z80 PIO with a software UART!  I'm not even sure where it gets its
  timing from, it could be software loops for all I know - I haven't seen
  a BIOS listing yet - and I understand that the BIOS routines are slow
  anyway, hence programs like TELCOM have their own.  I have plans to
  install the 8530 SCC chip - there is provision for it - one day.  I have
  a few programs I would love to run, but they expect either a dedicated
  SIO chip with a port address, or an entry point that can send and fetch
  characters with a minimum of fuss - like, all 8 bits at a time! :-)
  There are also certain other oddities which I won't go into just now. ]

Sorry for the long-winded posting, but I prefer to anticipate any questions
that may be asked.

-- 
Dave Horsfall (VK2KFU)         VK2KFU @ VK2RWI.NSW.AUS.OC
dave@ips.OZ.AU                  ...munnari!ips.OZ.AU!dave