The cairo-text-cluster-t structure holds information about a single text cluster. A text cluster is a minimal mapping of some glyphs corresponding to some UTF-8 text.

For a cluster to be valid, both num-bytes and num-glyphs should be non-negative, and at least one should be non-zero. Note that clusters with zero glyphs are not as well supported as normal clusters. For example, PDF rendering applications typically ignore those clusters when PDF text is being selected.

See the cairo-show-text-glyphs function for how clusters are used in advanced text operations.

(defcstruct cairo-text-cluster-t
  (num-bytes :int)
  (num-glyphs :int))  

num-bytes

The number of bytes of UTF-8 text covered by cluster.

num-glyphs

The number of glyphs covered by cluster.