Circos > Documentation > Tutorials > Quick Start > Text
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Use the latest version of Circos and read Circos best practices—these list recent important changes and identify sources of common problems.
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Don't know what question to ask? Read Points of View: Visualizing Biological Data by Bang Wong, myself and invited authors from the Points of View series.

1 — Quick Start

8. Text

Text tracks are a special 2-dimensional data track, which associates a text label with a genomic position.

Like with other tracks, text is limited to a radial range by setting r0 and r1

type  = text
file  = data/6/genes.labels.txt
r1    = 0.8r
r0    = 0.6r

You must set the font for the track, as well as the size of the labels. You can put in optional padding and rpadding to give the text margins.

label_font = light
label_size = 12p
rpadding   = 5p

text track rules

Rules for text tracks work in the same way as for all other track types.

In this example, I test the text label, via var(value), with a regular expression to make labels that contain "a" bold and those that contain "b" blue. I combine the rules by using flow=continue for the first rule. This way, a label can be both bold and blue.


condition  = var(value) =~ /a/i
label_font = bold
flow       = continue

condition  = var(value) =~ /b/i
color      = blue