cd_icc_utils_get_coverage ()

gboolean            cd_icc_utils_get_coverage           (CdIcc *icc,
                                                         CdIcc *icc_reference,
                                                         gdouble *coverage,
                                                         GError **error);

Gets the gamut coverage of two profiles where 0.5 would mean the gamut is half the size, and 2.0 would indicate the gamut is twice the size.