Re: "Movie" of plots

[John B. Thoo]

On Dec 14, 2004, at 6:39 AM, Claudio Belotti wrote:

> I think that it's better if you reply to the list, anyway :

I had sent Robert a reply off-list, but Claudio's mention above has 
prompted me to send the same reply to the list.  [I hope that you don't 
mind, Robert.]

On Dec 13, 2004, at 7:12 PM, John B. Thoo wrote:

> Perhaps if you can create gifs, you can use something like gifsicle to 
> create an animated gif.
>
> <http://www.lcdf.org/~eddietwo/gifsicle/>

Robert then asked me how I create gifs.  FWIW, here is what I sent him.

I have a rather convoluted way of making gifs (because I refuse to 
purchase s/w to do this alone when I don't do this very often).

First, I save my octave plots as .png using this script.

% A. S. Hodel
% Assoc. Prof, Dept. Elect & Comp Eng
% Auburn University, AL 36849-5201
% address@hidden

function printpng(filename,pngsiz,fn)
% function printpng(filename,pngsiz,fn)
% replot screen plot to a file
%
% inputs:
%   filename: string:
%   pngsiz: "small", "medium" (default), or "large"
%   fn: figure number to convert to png form (default: 0)
% no argument checking done

  if(nargin < 2)
    pngsiz = "small";
  elseif(isempty(pngsiz))
    pngsiz = "small";
  endif
  if(nargin < 3)
    fn =0;
  endif
  figure(fn);
  cmd = (sprintf(" gset terminal png %s color",pngsiz));
  eval(cmd);
  cmd = (sprintf("gset output '%s'", filename));
  eval(cmd);
  replot
  closeplot();
endfunction


Second, I open the files in the Gimp and re-save the plots as .xpm.

Third, I run this script.

#!/bin/sh
#
# A script to convert an X11 pixmap into a GIF image
# JBT 2003/1/22


if [ -z "$1" ] ; then
        echo 'usage: xpm2gif filename1 filename1 ...'
else
        for i in "$@" ; do
            filename="$i"
            if [ -e ${filename%.*}.xpm ] ; then
                xpmtoppm "$i" > "$i".temp1
                ppmquant 256 "$i.temp1" > "$i".temp2
                ppmtogif "$i".temp2 > "$i".temp3
                mv "$i".temp3 `echo "$i" | sed s/\.xpm/\.gif/g`
                rm -f "$i".temp1 "$i".temp2 "$i".temp3
            else
                echo "\"$i\" may not be an X11 pixmap (.xpm) file"
            fi
        done
fi


Last, I use gifsicle.  (You can fix the timing between frames in 
gifsicle.)

I'm sure there are simpler ways, and a query to the octave-help (or 
other) list may yield them.

HTH.
---John.



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