The collection of fonts in Vplot is small and goes back to so-called “Hershey fonts” (created originally by Dr. A.V. Hershey at the U. S. National Bureau of Standards).
You can use \F# directives to switch between different fonts.
In general, there are two sorts of escape sequences, those that take an argument and those that do not. Here is a complete list of escape sequences that do not take an argument:

  • \> Advance one interletter space
  • \< Back up one interletter space
  • \\^Raise one half of a capital letter height
  • \\_ Lower one half of a capital letter height
  • \g Continue processing text, but don’t actually print it (“ghostify it”).
    This is useful if you want to leave space to go back and add something by hand.
  • \G Start printing text again (“deghostify”)
  • \n Newline
  • \h Backspace (control-h also works) back up over the last character
  • \- Does nothing; used to prevent a group of characters from being formed into a ligature.
  • \\ Print a backslash

The following escape sequences take an integer argument immediately after, with a required space after the integer to delineate the end. This space is not printed.

  • \s# Size change. Change to # percent of the size set in the text vplot. \s100 restores the default height.
  • \f# Add # to current fatness. Goes out of effect when text printing is finished.
  • \F# Switch to font number #. (-1 restores the default font).
  • \k# Move by # space widths to the right (in percent; 100 = one space width). Negative numbers are allowed (moves left).
  • \r# Move up # character heights (in percent; 100 = the height of a standard capital letter). Negative numbers are allowed (moves down).
  • \v# Print ASCII character number # in the current font, stripping it of any special meaning. This and ligatures are the only way that glyphs numbered greater than 255 are available.
  • \c# Switch to color number #. \c-1 restores the current drawing color. Vplot’s current drawing color is not changed by changing the color inside text.
  • \m# Save current position in register number #.
  • \M# Restore position saved in register number #.

The following example is from rsf/rsf/sfgraph:

The line to create this title is 

title="\s100 \F11 Polinom CHebysheva + \F3 T\\_\s75 n\\^\s100 (cos \F10 q) = \F3 cos n\F10 q"

.
You can find a set of tests for different fonts in pens/tests:


Font 0
original (designed by Rob Clayton at Stanford)
Font 1
roman simplex
Font 2
roman duplex
Font 3
roman complex
Font 4
roman triplex
Font 5
italic complex
Font 6
italic triplex
Font 7
script simplex
Font 8
script complex
Font 9
greek simplex
Font 10
greek complex
Font 11
Cyrillic complex
\Font 12
German style gothic triplex
Font 13
Greek style gothic triplex
Font 14
Italian style gothic triplex
Font 15
mathematics
Font 16
miscellaneous

To display a particular font character by character on the screen, try something like

sfplas < RSFSRC/pens/fonts/cyrilc.vplot_font | \
xtpen xcenter=0 ycenter=0 scale=50 pause=1

Thanks to Joe Dellinger for help with this answer! For more information, see his presentation on Vplot and vplotttext.m.