function writepgm(image,filename)
%WRITEPGM Write a matrix as a raw pgm file
%         WRITEPGM(IMAGE,FILENAME) writes the array image as a raw PGM
%         file to FILENAME.
%
% Matthew Dailey 1999

if ~(image <= 255 & image >= 0)
  error('Image pixels out of range.');
end;

% Open the file
%fprintf(1,'Opening %s...\n',filename);
fid = fopen(filename,'w');

if fid <= 0
  error(sprintf('Could not open %s for writing.',filename));
end;

width = size(image,2);
height = size(image,1);

% Write header information
fprintf(fid,'P5\n');
fprintf(fid,'%d %d\n',width,height);
fprintf(fid,'255\n');

% Write the raw data -- transpose first though
count = fwrite(fid,image','uchar');

if count ~= width*height
  error(sprintf('Could not write all data to %s', outfile));
end;

fclose(fid);