Appendix B. PGPLOT Symbols
B.1 Character Encoding
The PGPLOT routines that display text, e.g.,
PGMTXT, generate a visible
representation of the characters supplied in a Fortran character
variable or constant. On most computer systems, a Fortran character
can take any of 256 values, numbered 0-255 (decimal). PGPLOT
interprets the values as follows:
The complete character encoding is displayed in Figure B.0. This is for the standard PGPLOT
roman font (font number 2); some of the symbols will differ from font
- These are used for the standard graph markers. On most
computer systems, they are non-printable control characters.
- PGPLOT interprets these according to the US-ASCII
character set, a subset of the ISO-Latin character sets, with one
exception: character number 94, which should be a circumflex (^), is
displayed as a degree symbol (°). The degree symbol is also
available as character 176, which should be used in preference;
eventually the display of character 94 will be corrected.
- These are unassigned; in the ISO-Latin character sets,
they are reserved for non-printable control characters.
- As far as possible, PGPLOT interprets these according
to the ISO-Latin-1 character set. In some cases, required accents are
omitted. I hope to rectify the omissions in a later version of PGPLOT.
Note that if your computer system does not use the ISO-Latin-1
character set, the output of a PGPLOT program will not correspond to
the characters in the source code.
B.2 Additional Symbols
An escape code allows a large number of additional symbols to
be displayed by PGPLOT. Each symbol is composed of a set of vectors,
based on digitized type fonts devised by A. V. Hershey of the US Naval
Postgraduate School, and is assigned a number in the range 0-4000.
Figures B.1 to B.7 show the graphical representation of all the
available symbols arranged according to Hershey's numerical sequence;
the blank spaces in this table represent ``space'' characters of
various widths. Note that not every number has an associated
character. Any character can be inserted in a text string using an
escape sequence of the form
nnnn is the 4-digit Hershey number.
Next: Appendix C
Tim Pearson, California Institute of Technology,
Copyright © 1996 California Institute of Technology