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January 2007

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2007.01.18 08:09 "TIFF fields alignment question", by <mikk@go2.pl>

2007.01.22 10:45 "(no subject)", by Gerben Vos

2007.01.22 10:45 "(no subject)", by Gerben Vos

mikk wrote:

> Does the TIFF specification require that fields such as first IFD offset,
> number of tags in a directory, tag structure and next IFD offset
> must be written at word aligned position in TIFF file?

Yes. TIFF6 spec, page 13: "The directory may be at any location in the
file after the header but must begin on a word boundary." The layout of the
an IFD then ensures that all elements are also on word boundaries.

For pointed-to data, see page 15: "The Value is expected to begin on a word
boundary".

Many TIFF reading applications also accept unaligned data (maybe with a
warning), but you shouldn't write such TIFFs.

There is no such restriction for the image data pointed to by the
StripOffsets field.

					Gerben Vos.