[GRASSLIST:359] Re: NVIZ : getting a script to run

[Soil & Water Lab.]

> Use the ImageMagick tools:
> pnmtopng < dump.ppm > dump.png
> sgitopnm < dump.rgb | pnmtopng > dump.png

The question is : does it work *inside* the nviz script ? Does "dump" 
correspond to a temp file created during the script, before the picture gets 
its proper name ? If not, well, back to the beginning.

Actually, I thought about a workaround: instead of relying on nviz to loop on 
the maps, I'd rely on my bash parent. That way, I'd write only one PPM that I 
could convert on the fly. Besides, I feel I would have some troubles with 
very long image list in nviz, whereas bash could handle it OK. 

The problem I foresee is that it's gonna take a looong time, to start nviz, 
load the state export, close, start over. So maybe an intermediary solution, 
10 maps by 10 maps (I have about 900maps, you can imagine my pb). 


> and to make YUV files for mpeg2enc (mjpeg tools) use:
> ppmtoyuv
> mencoder from the mplayer people may also be helpful to you.

I've never been able to understand the parameters of the MPEG2 algorithm, 
there are far toomany parameters for me. I had some fairly nice results with 
MPEG1 (with conversion ppm-png embedded). Or fli (with pbm2fli). Gifsicle is 
nice indeed, but there was this patent problem with GIFs that limited its 
utilisation. 
Or MNG, but it's not recognized by many softwares.



> re. double buffered screen dumps and key-frame animation scripting- you
> might try the CVS version of NVIZ.. there seems to be a lot of good
> things happening there right now.

Great ! Can I compile the latest version of NVIZ on a old version of GRASS ? 
IS there a pb of backward compatibility ?

>> I quit nviz (still staying  in the parent script)
> > ?
>
> killall nviz
> ;)
> but maybe you want something cleaner.

Well, "killall nviz" is  a bit too much "shock and awe" for me ;-)


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Soil & Water Lab.
Biological and Environmental Engineering Dept.
Cornell University
222 Riley-Robb Hall
ITHACA, NY 14853 - USA
Tel : 607-255-2463/1819
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