 has been frozen */
fooPreEncode(tif, sample)/* called once per strip/tile, before the first row in
			    a strip/tile is encoded */
fooEncode*(tif, bp, cc, sample)/* encode cc bytes of user data (bp) */
    fooEncodeRow(...)	/* called to decode a single scanline */
    fooEncodeStrip(...)	/* called to decode an entire strip */
    fooEncodeTile(...)	/* called to decode an entire tile */
fooPostEncode(tif)	/* called once per strip/tile, just before data is written */
fooSeek(tif, row)	/* seek forwards row 