slackbuilds/desktop/cairo-clock/README

It is an analog clock displaying the system-time. It leverages
the new visual features offered by Xorg 7.0 in combination with a
compositing-manager (xcompmgr, compiz, compton), gtk+ 2.10.0,
cairo 1.2.0, libglade 2.6.0 and libsrvg 2.14.0 to produce a time
display with pretty-pixels.

*Attention*, by default cairo-clock runs with a refresh rate at
30 which might lead to high cpu usage by X process (and compton
when used). To prevent this it is better  to run cairo-clock with
a refresh rate at 1 (see option --refresh).