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[Octave-bug-tracker] [bug #44118] imwrite saves wrong pixel values into

From: Carnë Draug
Subject: [Octave-bug-tracker] [bug #44118] imwrite saves wrong pixel values into jpg file
Date: Fri, 30 Jan 2015 15:33:18 +0000
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Firefox/31.0 Iceweasel/31.4.0

Follow-up Comment #6, bug #44118 (project octave):

GraphicsMagick does all kind of smart things and converts images between types
in a way that is not clear to me.  Sometimes converts RGB to indexed if it
sees to few different colors. An RGB image may be shown as grayscale if all
channels are the same. Sometimes does this, sometimes it does not. I know this
is not acceptable for scientific computing where the exact numbers and image
type matter. I feel that this means that GraphicsMagic is not a good choice
for Octave anymore but replacing it is more work that what I can do.  If you
can can do it, patchs are welcome, if you cannot and you need this, I am sure
you can find people who will do it (although not for free).

If you have nothing to offer to anyone, I recommend you use tiff then, it
seems to work better.  An alternative is to use bioformats. It is a Matlab
package and you can make it work in Octave with half dozen changes in m


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