RFC 553 (rfc553) - Page 1 of 19

Draft design for a text/graphics protocol

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Network Working Group                                            C. Irby
Request for Comments: 553                                      K. Victor
NIC: 17810                                                       SRI-ARC
                                                            14 July 1973


               Draft design for a text/graphics protocol

DRAFT DESIGN FOR A TEXT/GRAPHICS PROTOCOL

   This proposal should be seen as a synthesis of existing ideas rather
   than an attempt to put forth new ones.  It is based on work by the
   NGG, Elaine Thomas, Peter Deutsch, Charles Irby, Ken Victor, Bill
   Duvall, Bob Sproull, and others at ARC, PARC, and BBN.

   We are concerned about the lack of text-handling capabilities of the
   protocol suggested in RFC 493.  Also, we feel that the protocol will
   have a significant influence on the interface provided to writers of
   future graphics application programs, and consequently that such
   things as "beam twiddling" should not be part of the protocol.

      Things of this nature address the problem at too low a level for a
      facility which is intended to service the needs of a wide range of
      graphics devices.

      We feel that, although the breakdown into "levels" as proposed in
      RFC 493 may be expedient for initial experimentation, it is
      inappropriate for a Network Standard Protocol.  Instead, we
      propose that the protocol allow for two levels, segmented and
      structured.  This allows the writers of graphics application
      programs to deal with a very simple display facility (segments
      consisting of lines, dots, or character strings) or with a
      powerful structure of display subroutines.

   We propose an experimental implementation of such a scheme on the
   ARC, BBN, and PARC systems to test these ideas using several
   application programs (including NLS) and at least an IMLAC, ARDS, and
   an E&S LDS.

Environment

   We are trying to design a protocol used to communicate with a
   "virtual display" to operate at the other end of a wire (ARPANET
   connection) from a "host" which is running some kind of display
   application program.






Irby, et. al.
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