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Date: 16 Aug 2002 8:23:56 +0100
From: Andreas_Kleinert@t-online.de (Andreas R. Kleinert)
Subject: Re: Orientation field
To: "Jon Saxton" <js@triton.vg>
In-Reply-To: <20020815005239.TXCN8671.out013.verizon.net@thalassa>
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>Mind you, not supporting the orientation tag is pure laziness.  For the writer

 As - in most cases - also is writing images bottom-up.
 That is: lazyness.

 Some points to consider:

 1. If there's not much code involved, why write bottom-up anyway?

      a) Because the corresponding device does it this way.

         If so: why does it *and* why should this image be destined for
         display by an image viewer then, in the first place?

         Examples: Scanners. But you always could flip the original,
                   before scanning.

      b) Because the used frame-buffer is organized this way.

         If so: if it's a random-access memory, a bit of arithmetics
                (basically the same as for a flip-operation but without
                the need for extra memory) will help.

         Examples: a bottom-up frame buffer memory (simply read from
                   'native' bottom-right to upper-left and flip it this way)

 2. If memory consumption is not an issue, why not flip on/after the source
    instead of inside the TIFF viewer?

      a) Because it's a different kind of device with different restrictions.

         But why not at least write as many "strips" as there are "rows",
         with a "rows per strip" of one and then re-arrange (sort) the strips?
         (i.e. the offsets of the strips)

      b) Because those TIFFs can be upto 4 GB (etc.)

         Well, too large for PCs, either. See a)

 3. Where's the problem in batch-converting a bunch of wrongly oriented
    images right after creation?

      ...
--
Andreas_Kleinert@t-online.de  | http://www.ar-kleinert.de             |
Freelance Consultant & Writer | Software Engineering                  |
 *** PerSuaSiVe SoftWorX ***  | x86 Win/Linux, 68k/PPC Amiga and more |


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