Name:         grsy00

Purpose:      initialize font definition

Category:     GRAPHICS

File:         pgplot.src

Author:       T.J. Pearson

Use:          see description below.

Description:

            SUBROUTINE GRSY00
      
       This routine must be called once in order to initialize the tables
       defining the symbol numbers to be used for ASCII characters in each
       font, and to read the character digitization from a file.
      
       Arguments: none.
      
       Implicit input:
        The file with name specified in environment variable PGPLOT_FONT
        is read, if it is available.
        This is a binary file containing two arrays INDEX and BUFFER.
        The digitization of each symbol occupies a number of words in
        the INTEGER*2 array BUFFER; the start of the digitization
        for symbol number N is in BUFFER(INDEX(N)), where INDEX is an
        integer array of 3000 elements. Not all symbols 1...3000 have
        a representation; if INDEX(N) = 0, the symbol is undefined.
      
      *  PGPLOT uses the Hershey symbols for two `primitive' operations:
      *  graph markers and text.  The Hershey symbol set includes several
      *  hundred different symbols in a digitized form that allows them to
      *  be drawn with a series of vectors (polylines).
      *
      *  The digital representation of all the symbols is stored in common
      *  block /GRSYMB/.  This is read from a disk file at run time. The
      *  name of the disk file is specified in environment variable
      *  PGPLOT_FONT.
      *
      * Modules:
      *
      * GRSY00 -- initialize font definition
      * GRSYDS -- decode character string into list of symbol numbers
      * GRSYMK -- convert marker number into symbol number
      * GRSYXD -- obtain the polyline representation of a given symbol
      *
      * PGPLOT calls these routines as follows:
      *
      * Routine          Called by
      *
      * GRSY00          GROPEN
      * GRSYDS          GRTEXT, GRLEN
      * GRSYMK          GRMKER,
      * GRSYXD          GRTEXT, GRLEN, GRMKER
      ***********************************************************************

Updates:      Oct 16, 1998: JPT automatically extracted from source.