``ppm.m''

%# Usage: ppm(fname,red,green,blue)
%#
%# Output- color ppm image in file "fname" (view with "xli fname").
%# Input- red, green, blue: 2d data of red, green, blue intensities

function ppm(fname,red,green,blue)
  %# Enlarge image
  for en=1:4
    red=smooth(red); green=smooth(green); blue=smooth(blue);
  endfor
  
  pixmx=255;
  height=size(red,1); width=size(red,2);   
  mx=max(max([red, green, blue]));
  mn=min(min([red, green, blue]));

  fid=fopen(fname,'w');
  fprintf(fid,'P3\n');
  fprintf(fid,'%d %d\n',width,height);
  fprintf(fid,'%d\n',pixmx);
  
  dat=([reshape(red',1,width*height); ...
        reshape(green',1,width*height); ...
        reshape(blue',1,width*height)] ...
           -mn)/(mx-mn)*pixmx;
  
  fprintf(fid,'%d ',dat);
  fclose(fid);
endfunction