Circos > Documentation > Tutorials > Quick Start > Text
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Circos at the EMBO NGS workshop in Tunis, Sept 15–25.

Use the latest version of Circos and read Circos best practices—these list recent important changes and identify sources of common problems.
If you are having trouble, post your issue to the Circos Google Group and include all files and detailed error logs. Please do not email me directly unless it is urgent—you are much more likely to receive a timely reply from the group.
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

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

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.

<rules>

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

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

</rules>