DirectFB Reference Manual
IDirectFBSurface   SetDstColorKey

Set the destination color key, i.e. the only color that gets overwritten by drawing and blitting to this surface when destination color keying is enabled.

SetDstColorKey (
	IDirectFBSurface		*	thiz,
	__u8			r,
	__u8			g,
	__u8			b
);