gnuplot documentation

77 TERMINAL gnuplot 4.3 187
’abc&{def}ghi’
would produce
’abc
ghi’.
The ’˜ ’ character causes the next character or bracketed text to be overprinted by the following character
or bracketed text. The second text will be horizontally centered on the first. Thus ’˜ a/’ will result in
an ’a’ with a slash through it. You can also shift the second text vertically by preceding the second text
with a number, which will define the fraction of the current fontsize by which the text will be raised or
lowered. In this case the number and text must be enclosed in brackets because more than one character
is necessary. If the overprinted text begins with a number, put a space between the vertical offset and
the text (’˜ {abc}{.5 000}’); otherwise no space is needed (’˜ {abc}{.5 — }’). You can change the font
for one or both strings (’˜ a{.5 /*.2 o}’ — an ’a’ with a one-fifth-size ’o’ on top — and the space between
the number and the slash is necessary), but you can’t change it after the beginning of the string. Neither
can you use any other special syntax within either string. You can, of course, use control characters by
escaping them (see below), such as ’˜ a{\^}’
You can access special symbols numerically by specifying \character-code (in octal), e.g., {/Symbol
\245} is the symbol for infinity.
You can escape control characters using \, e.g., \\, \{, and so on.
But be aware that strings in double-quotes are parsed differently than those enclosed in single-quotes.
The major difference is that backslashes may need to be doubled when in double-quoted strings.
Examples (these are hard to describe in words — try them!):
set xlabel ’Time (10^6 {/Symbol m}s)’
set title ’{/Symbol=18 \362@_{/=9.6 0}^{/=12 x}} \
{/Helvetica e^{-{/Symbol m}^2/2} d}{/Symbol m}’
The file "ps guide.ps" in the /docs/psdoc subdirectory of the gnuplot source distribution contains more
examples of the enhanced syntax.
77.53.2 Editing postscript
The PostScript language is a very complex language — far too complex to describe in any detail in
this document. Nevertheless there are some things in a PostScript file written by gnuplot that can be
changed without risk of introducing fatal errors into the file.
For example, the PostScript statement "/Color true def" (written into the file in response to the command
set terminal postscript color), may be altered in an obvious way to generate a black-and-white version
of a plot. Similarly line colors, text colors, line weights and symbol sizes can also be altered in straightforward
ways. Text (titles and labels) can be edited to correct misspellings or to change fonts. Anything
can be repositioned, and of course anything can be added or deleted, but modifications such as these
may require deeper knowledge of the PostScript language.
The organization of a PostScript file written by gnuplot is discussed in the text file "ps file.doc" in the
docs/ps subdirectory of the gnuplot source distribution.
77.53.3 Postscript fontfile
The fontfile or fontfile add option takes one file name as argument and encapsulates this file into the
postscript output in order to make this font available for text elements (labels, tic marks, titles, etc.).
The fontfile delete option also takes one file name as argument. It deletes this file name from the list
of encapsulated files.
The postscript terminal understands some font file formats: Type 1 fonts in ASCII file format (extension
".pfa"), Type 1 fonts in binary file format (extension ".pfb"), and TrueType fonts (extension ".ttf").
Pfa files are understood directly, pfb and ttf files are converted on the fly if appropriate conversion tools
are installed (see below). You have to specify the full filename including the extension. Each fontfile
option takes exact one font file name. This option can be used multiple times in order to include more
than one font file.