cairo-set-fill-rule (cr rule)

cr -- a cairo-t context
rule -- a fill rule, specified as a cairo-fill-rule-t value

Set the current fill rule within the Cairo context. The fill rule is used to determine which regions are inside or outside a complex, potentially self-intersecting, path. The current fill rule affects both the cairo-fill and cairo-clip functions. See the cairo-fill-rule-t enumeration for details on the semantics of each available fill rule.

The default fill rule is :winding.