Name:         PGPT1

Purpose:      draw one graph marker

Category:     GRAPHICS

File:         pgplot.src

Author:       T.J. Pearson

Use:          see description below.

Description:

            SUBROUTINE PGPT1 (XPT, YPT, SYMBOL)
            REAL XPT, YPT
            INTEGER SYMBOL
      
       Primitive routine to draw a single Graph Marker at a specified point.
       The marker is drawn using the current values of attributes
       color-index, line-width, and character-height (character-font applies
       if the symbol number is >31).  If the point to be marked lies outside
       the window, no marker is drawn.  The "pen position" is changed to
       (XPT,YPT) in world coordinates.
      
       To draw several markers with coordinates specified by X and Y
       arrays, use routine PGPT.
      
       Arguments:
        XPT    (input)  : world x-coordinate of the point.
        YPT    (input)  : world y-coordinate of the point.
        SYMBOL (input)  : code number of the symbol to be drawn:
                          -1, -2  : a single dot (diameter = current
                                    line width).
                          -3..-31 : a regular polygon with ABS(SYMBOL)
                                    edges (style set by current fill style).
                          0..31   : standard marker symbols.
                          32..127 : ASCII characters (in current font).
                                    e.g. to use letter F as a marker, let
                                    SYMBOL = ICHAR('F'). 
                          > 127  :  a Hershey symbol number.

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