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Date:	Mon, 27 Sep 2010 08:03:42 +0000 (GMT)
From:	Marco Atzeri <marco_atzeri AT yahoo DOT it>
Subject:	Update graphicsmagick with quantum depth = 16
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Dear users,
I am thinking to update GraphicsMagick-1.3.12
moving from "quantum depth =3D 8" to "quantum depth =3D 16"

following a discussion on octave bug list
http://savannah.gnu.org/bugs/?30715
about the improved image quality using the higher quantum depth,
specially for medical and scientific images.

For details about the difference
http://www.graphicsmagick.org/INSTALL-unix.html
-------------------------------------------------------------
Larger pixel quantums cause GraphicsMagick to run more slowly and to requir=
e more memory. For example, using sixteen-bit pixel quantums causes Graphic=
sMagick to run 15% to 50% slower (and take twice as much memory) than when =
it is built to support eight-bit pixel quantums.

The amount of virtual memory consumed by an image can be computed by the eq=
uation (QuantumDepth*Rows*Columns*5)/8. This is an important consideration =
when resources are limited, particularly since processing an image may requ=
ire several images to be in memory at one time. The following table shows m=
emory consumption values for a 1024x768 image:

    QuantumDepth 	Virtual Memory
    8 	                3MB
    16 	                8MB
    32 	                15MB

GraphicsMagick performs all image processing computations using double-prec=
ision floating point so results are very accurate. Increasing the quantum s=
torage size decreases the amount of quantization noise (usually not visible=
 at 8 bits) and helps prevent countouring and posterization in the image.
------------------------------------------------------------

Anyone having problem with it ?
Of course I will update octave to use this improvement.

Regards
Marco Atzeri=20





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