Appendix B. PGPLOT Symbols
B.1 Character Encoding
The PGPLOT routines that display text, e.g., PGTEXT,
PGMTXT, and 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:
- 0-31
- These are used for the standard graph markers. On most
computer systems, they are non-printable control characters.
- 32-127
- 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.
- 128-159
- These are unassigned; in the ISO-Latin character sets,
they are reserved for non-printable control characters.
- 160-255
- 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.
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
to font.
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), where
nnnn is the 4-digit Hershey number.
Next: Appendix C
PGPLOT
Tim Pearson, California Institute of Technology,
tjp·astro.caltech.edu
Copyright © 1996 California Institute of Technology