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From: dnwiebe@CIS.OHIO-STATE.EDU (Dan N Wiebe)
Newsgroups: comp.graphics
Subject: Low-level question about TIFF (not general interest)
Message-ID: <9009211515.AA01105@melon.cis.ohio-state.edu>
Date: 21 Sep 90 15:15:11 GMT
Sender: dnwiebe@tut.cis.ohio-state.edu
Lines: 28


	I'm trying to write a TIFF reader/writer library (thanks for the
suggestion, but libtiff won't work), and I've got a question about
the strip order of multichannel (RGB, etc.) images that are in multi-plane
configuration (PlanarConfiguration = 2).
	First of all, I'm assuming that such images are stored in such a
way that any given strip contains data from only one image channel--that
a plane consists of an integral number of strips.  I don't know this for
sure, but it would seem that anything else would be uselessly complicated
to decode.  Correct me if I'm wrong.
	The question:  are strips stored in round-robin or group fashion?
Suppose I have a three-channel (RGB) image with nine strips--i.e., each
plane is three strips long.  Are they stored like

		R1 R2 R3 G1 G2 G3 B1 B2 B3

or like

		R1 G1 B1 R2 G2 B2 R3 G3 B3

?  Or perhaps in some other way that I haven't thought of?  (Note that
I'm talking about *strips* here, not individual values, and I'm only
interested in the situation where PlanarConfiguration is 2 (multiple).)
	As this is a fairly vertical-interest question, please e-mail any
replies directly to dnw@oclc.oclc.org.
	Thanks for the info...

Dan Wiebe