graphicsmagick-help

[Bob F. <bfr...@si...>]

The latest GraphicsMagick snapshot (GraphicsMagick-1.1-20030924,
"ftp://ftp.graphicsmagick.org/pub/GraphicsMagick/snapshots/GraphicsMagick-1=
=2E1-20030924.tar.gz")
resolves this problem.  The TIFF coder now supports writing color
colormapped images with 1, 2, 4, and 8 bits per sample, allowing file
sizes to be much smaller.  Writing grayscale images is still
(unnecessarily) limited to 1 and 8 bits per pixel.

There is some risk that programs exist that don't handle 1 & 2 bits
per sample since the TIFF spec only mentions 4 & 8 bits per sample in
its baseline specification.  Please let me know if this becomes a
problem.  If it is a problem, we will find a way to make the more
compact sizes optional.

Bob

On Wed, 24 Sep 2003, gerard coing wrote:

> Hello
> I have a lot of TIFF images to optimize (4000X4000 px, 256 colors, 15
> Mo each, used as map background in a SIG).
> So I tried :
> gmconvert -colors 16 IN.tif OUT.tif
> But weight is still the same. Doing :
> identify -verbose OUT.tif :
> Colors: 256
>      0: ( 48, 43, 45)      #302B2D
=2E
=2E
=2E
>      255: (  0,  0,  0)    black
>    Filesize: 15.3m
> Is there a way to get rid of the 240 unusefull black colors from the
> palette ?
> Doing :
> gmconvert -colors 16 IN.tif OUT.png
> works perfectly well (really 16 colors) and reduces file size to 3.8Mo
> but with a zip compression.
> Can I get an uncompressed PNG file ?
>
> Best regards
> Gerard Coing
> photographie et multimedia
> Drac de Lorraine
> Service de l'Inventaire du Patrimoine
> 29 rue du Haut-Bourgeois
> 54000 Nancy
> m=E9l : ger...@cu...
> t=E9l Nancy : 03 83 32 90 63
> t=E9l Metz : 03 87 56 41 19
> t=E9l portable : 06 84 96 66 33
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=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
Bob Friesenhahn
bfr...@si...
http://www.simplesystems.org/users/bfriesen