[GRASS5] Re: [NVIZ] Code for PPM dumps

[Andreas Lange]

Markus,

the big endian/little endian part of the code will give problems, as not
only sun machines are big-endian. There are more general solutions, have
a look at tifflib. There must be other code within grass where this
problem is solved, but i have currently no time to search. I don't know
exactly if a config-solution or a solution within the code is better,

cu,

Andreas

Markus Neteler wrote:
> 
> Hi Bob,
> 
> many thanks for your patches. I have applied them to CVS
> (hope it's o.k. for all developers). The PPM format is
> more common than the SGI image format. Probably a selection
> window on image format would be perfect.
> 
> On Sun, Sep 24, 2000 at 10:51:04PM -0300, Bob Covill wrote:
> > Hello,
> >
> > I am attatching to this e-mail the code I have added to NVIZ to dump
> > images to a PPM format. I have written out the installation steps, so
> > hopefully it is not to complicated.
> >
> > The first two files that should be incorporated are "Gmakefile" and
> > "gsd_img_ppm.c". These two files should be copied to
> > "$GISBASE/src/libes/ogsf". The "gsd_img_ppm.c" is a modified version of
> > the routine to dump RGB files. It creates a new library routine entitled
> > "G_write_ppm".
> Here your Gmakefile does not fit any more to the current Gmakefile as
> file name conflicts on Windows had to be fixed earlier this summer. I
> have adjusted it, it compiles o.k. now.
> 
> > Note the image dump routine is byte order sensitive. The file
> > "gsd_img_ppm.c" is currently set for a big-endian machine (eg. SUN). To
> > build the library on a small-endian (linux) machine comment out lines 34
> > to 36, and uncomment lines 38 to 40. There is a note in the code where
> > this needs to be done. After copying the new files execute gmake5 to
> > rebuild the ogsf library.
> 
> Here I have inserted a #ifdef statement.
> 
> #ifdef SUN
>  /*big endian*/
>   ...
> else
>  /*little endian*/
>   ...
> #endif
> 
> I think something with config.h to detect little/big endian would be
> better than hard-code the platform names here. Feel free to modify it.
> 
> > The next two files; "anim_support.c" and "init_commands.c" should be
> > copied to $GISBASE/src.contrib/GMSL/NVIZ2.2/src. These files will
> > overwrite existing files. These files utilize the above PPM lib routine
> > and create an NVIZ command entitled "Nwrite_ppm". This is the command
> > that will be called from the nviz scripts. After adding the above two
> > files, execute gmake5 to rebuild the NVIZ2.2 executable to incororate
> > the new command.
> >
> > After completing the above, three TCL scripts can be modified to execute
> > the new dumping routine. The scripts are; "nviz2.2_script",
> > "panel_animation.tcl", and "panel_kanimator.tcl".  I have also attached
> > these three scripts. They can be placed in
> > $GISBASE/src.contrib/GMSL/NVIZ2.2/scripts.
> >
> > With the above changes execute gmake5 from
> > $GISBASE/src.contrib/GMSL/NVIZ2.2 to install the updated scripts in the
> > proper location.
> >
> > Images should now be dumped to a *.ppm format.
> Yes, working o.k. on Linux (no bad magic number problems!).
> 
> > If there are any problems or questions let me know. I have built and
> > used the routines on both a Sun Sparc and Linux.
> > --
> > Bob Covill
> >
> > Tekmap Consulting
> > P.O. Box 2016
> > Fall River, N.S.
> > B2T 1K6
> > Canada
> >
> > E-Mail: bcovill at tekmap.ns.ca
> > Phone: 902-860-1496
> > Fax: 902-860-1498
> >
> 
> Many thanks, Bob. Your contribution will become part of the next GRASS 5
> release.
> 
> Kind regards
> 
>  Markus Neteler
> 
> --
> Dipl.-Geogr. Markus Neteler *  University of Hannover
> Institute of Physical Geography and Landscape Ecology
> Schneiderberg 50 * D-30167 Hannover * Germany
> Tel: ++49-(0)511-762-4494  Fax: -3984
> 
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-- 
Andreas Lange, 65187 Wiesbaden, Germany, Tel. +49 611 807850
Andreas.Lange at Rhein-Main.de - A.C.Lange at GMX.net


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