Circos understands TTF (TrueType) and OTF (OpenType) fonts.

Several fonts are included in Circos for labels and glyphs. This file
describes these fonts and covers how you can add your own.

GD TTF COMPATIBILITY

Your GD Perl module (interface to libgd) must be compiled with TTF font support. If it is not, fonts will not be rendered - Circos will create an error:

  There was a problem with True Type font support. Circos could not render text from the font
  file _FONTFILE_. Please check that gd (system graphics library) and GD (Perl's interface to gd) 
  are compiled with True Type support


FONT DEFINITIONS

Circos font definitions are found in the <fonts> block, where a unique
name is assigned to each font file. A font can be defined by multiple
names (e.g. default, plain, normal), but a given name can only be used
once (e.g. you cannot have two fonts named 'default').

Fonts that are already included are defined in etc/fonts.conf

# etc/fonts.conf

serif_roman    = fonts/modern/cmunrm.otf
serif_default  = fonts/modern/cmunrm.otf
serif_normal   = fonts/modern/cmunrm.otf
serif_bold     = fonts/modern/cmunbx.otf
serif_italic   = fonts/modern/cmunui.otf

light          = fonts/modern/cmunss.otf
normal         = fonts/modern/cmunss.otf
default        = fonts/modern/cmunss.otf
condensed      = fonts/modern/cmunss.otf
semibold       = fonts/modern/cmunbsr.otf
condensedbold  = fonts/modern/cmunbsr.otf
bold           = fonts/modern/cmunsx.otf
...

Relative file paths are relative to the circos distribution. 


INCLUDED FONTS


Computer Modern (fonts/modern)

The family of faces composing the standard for typesetting in computer
science and, in general, TeX. Created by David Knuth. See
http://en.wikipedia.org/wiki/Computer_Modern. Serif, sans-serif and
monospaced versions are included. The fonts/modern directory contains
more faces than defined in etc/fonts.conf - add others if you wish.


Symbols (fonts/symbols)

Circle and polygon glyphs of various spacings by Martin Krzywinski.



SUGGESTED FONTS

The following fonts are not included, but can be downloaded. Once
you've downloaded the font, see below (ADDING FONTS) to learn how to
add the font to Circos.

Circlethings (fonts/circles)
http://www.dafont.com/circle-things.font

Two fonts containing various circular glyphs from Fonts &
Things. Useful for glyph tracks and champagne plots. These tracks are
described at

http://mkweb.bcgsc.ca/dev/circos/tutorials/lessons/2d_tracks/glyphs/


Pointers (fonts/pointers)
http://www.dafont.com/pointers.font

Font of arrows and pointers by Russ Rowlett. Useful for arrow ends and callouts. To create arrow ends, see

http://mkweb.bcgsc.ca/dev/circos/tutorials/lessons/recipes/directed_links/
 

BasicShapes1 (fonts/shapes)
http://www.dafont.com/fnt-basicshapes1.font

A variety of shapes and glyphs, similar to the Windows' wingding font, by Fonts & Things.


ADDING FONTS

To add a font, it must be either TTF or OTF format. Add its definition
to the etc/fonts file, or directly to the <fonts> block. For example,
either

# etc/fonts.conf
...
# font definition
mynewfont = /path/to/myfont.ttf
# now use font using 'mynewfont' as the font name
# e.g. label_font = mynewfont

or, in circos.conf

<fonts>
# included fonts
<<include etc/fonts.conf>>
# your font definitions
mynewfont = /path/to/myfont.ttf
</fonts>

If you have a large number of new fonts, consider bundling them in
your own font file and including this file from etc/fonts.conf

# etc/fonts.conf
...
<<include /path/to/myfonts.conf>>