RFC 94 (rfc94) - Page 2 of 6

Some thoughts on Network Graphics

RFC 94             Some Thoughts on Network Graphics       February 1971


   compare "window".  The problem was not treated of supplying
   parameters identifying structure for match, etc. that are not actual
   display commands.

   Perhaps some necessary information gathering (i.e., the display
   hardware descriptions and the characteristics of every node) is
   preliminary to the generation of a detailed specification.  It is
   important that, without delay, a mechanism be defined for gathering
   and collating this information in such a way that it doesn't deter
   progress on Network graphics development.

Some General Extensions to the Note 86 Proposal

   1. DISPLAY LANGUAGE CAPABILITIES SHOULD ENCOMPASS THE UNION OF
      CURRENT AND ANTICIPATED NETWORK GRAPHICS HARDWARE.  Our experience
      in exploring interactive graphics communication techniques for use
      by researchers and non-programmers indicates that this is not just
      a "motherhood".  The utility of such applications programs depends
      highly upon incorporating sophisticated graphics hardware.  In
      absence of those features, some programs simply won't be used.

   2. THE DATA STRUCTURE SHOULD ALLOW LOGICAL AS WELL AS PICTORIAL
      REPRESENTATION OF THE USER'S PROBLEM.  This close coupling of the
      meaning of a picture with the actual picture is desirable from a
      processing program's point of view, especially if a user is to
      interact with the picture.  We have found this an efficient way to
      operate with the GRAIL Project and its derivatives here at Rand.
      This technique is included in a recently proposed graphics
      language generated by Bob Anderson (Rand) and Ben Wegbreit
      (Harvard).

   3. TRANSMIT DEFINITIONS OF GRAPHICS AND THEN INSTANCES OF THEIR USE.
      The attempt here is to raise the level of "conversation" between
      programs (where possible) and to reduce processing overhead.  For
      example, if one wishes to draw lots of resistors, why not
      graphically define a resistor once and then transmit instances by
      giving the definition name accompanied by attributes? A typical
      form of an instance is shown below.

         Item Name (position, size, intensity, scaling, labeling,
                    rotation, etc.)

      There are many examples of this approach such as the recent work
      by William Newman (Utah) and many earlier studies at MIT.

   4. PARTITION THE DISPLAY STRUCTURE FOR 1) STATIC VS. DYNAMIC
      INFORMATION, AND 2) CONTEXT.  As opposed to refreshing an entire
      picture whose domain is the entire screen, we have found it useful



Harslem, et. al.