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1993.06.11 05:05 "TIFF - T4 2D subtleties", by Brian Rippon
1993.06.21 21:07 "Re: TIFF - T4 2D subtleties", by Sam Leffler

1993.06.21 21:07 "Re: TIFF - T4 2D subtleties", by Sam Leffler

    To:      tiff@sgi.sgi.com
    Subject: TIFF - T4 2D subtleties
    From:    Brian Rippon <brian@advent.demon.co.uk>
    Date:    Thu, 10 Jun 93 18:05:19 A

    
    In implementing Group3, 2D, TIFF files, there seems to be
    confusion concerning the positioning of the EOL+1 and EOL+0's
    relative to byte boundaries, strips (and tiles).

    TIFF6 says that fill bits, if added, are such that EOL always
    ends on a byte boundary.

    I think tifflib interprets the spec by ensuring that EOL+1 or
    EOL+0 always ends on a byte boundary. Doesn't this contradict the
    spec?

    Secondly, does a strip (or tile) always commence with EOL+1?
    If so, the last row in a strip does not contain an EOL, only
    fill bits, so up to 10 fill bits may occur before the EOL.
    Or should the 1 be at the start of the strip (except for the
    first strip, which starts EOL+1)?

    Any views? Or is it formally defined somewhere?

At one time the library aligned the bits such that the
tag bit that follows the EOL code was included in the
byte-aligned data.  This was wrong and was fixed in 
February of last year.

	Sam