function strcenter(lines, offset)
%STRCENTER Center each line of text.
%
%   STRCENTER(LINES, OFFSET) where LINES is a cell array of lines and OFFSET is
%   a non-negative integer, does a centering of the text in each line relative
%   to the specified offset.  If OFFSET is omitted, 72 is used.

%   Author:      Peter John Acklam
%   Time-stamp:  2003-10-13 11:13:48 +0200
%   E-mail:      pjacklam@online.no
%   URL:         http://home.online.no/~pjacklam

   error(nargchk(1, 2, nargin));
   if nargin < 2
      offset = 72;
   end

   spc = ' ';
   tab = sprintf('\t');
   lines = lines(:);

   for i = 1:length(lines)
      k = find(lines{i} ~= spc & lines{i} ~= tab);
      if isempty(k)
         lines{i} = '';
      else
         linlen = k(end) - k(1) + 1;
         padlen = floor((offset - linlen)/2);
         lines{i} = [spc(:,ones(padlen,1)) lines{i}(k(1):k(end))];
      end
   end