function ch = getkey(wait)

% GETKEY - get a single keypress
%   CH = GETKEY waits for a keypress and returns the ASCII code. Accepts
%   all ascii characters, including backspace (8), space (32), enter (13),
%   etc, that can be typed on the keyboard. Non-ascii keys (ctrl, alt, ..)
%   return a NaN. CH is a double. 
%
%   CH = GETKEY('non-ascii') uses non-documented matlab 6.5 features to
%   return a string describing the key pressed. In this way keys like ctrl, alt, tab
%   etc. can also distinguished. CH is a string.
%
%   This function is kind of a workaround for getch in C. It uses a modal, but
%   non-visible window, which does show up in the taskbar.
%   C-language keywords: KBHIT, KEYPRESS, GETKEY, GETCH
%
%   Examples:
%
%    fprintf('\nPress any key: ') ;
%    ch = getkey ;
%    fprintf('%c\n',ch) ;
%
%    fprintf('\nPress the Ctrl-key: ') ;
%    if strcmp(getkey('non-ascii'),'control'),
%      fprintf('OK\n') ;
%    else
%      fprintf(' ... wrong key ...\n') ;
%    end
%
%  See also INPUT, CHAR

% for Matlab 6.5
% version 1.1 (dec 2006)
% author : Jos van der Geest
% email  : jos@jasen.nl
%
% History
% 2005 - creation
% dec 2006 - modified lay-out and help

% Determine the callback string to use
%if nargin == 1,
 %   if strcmpi(m,'non-ascii'),
  %      callstr = ['set(gcbf,''Userdata'',get(gcbf,''Currentkey'')) ; uiresume '] ;
   % else       
    %    error('Argument should be the string ''non-ascii''') ;
   % end
%else
    callstr = ['set(gcbf,''Userdata'',double(get(gcbf,''Currentcharacter''))) ; uiresume '] ;
%end

% Set up the figure
% May be the position property  should be individually tweaked to avoid visibility
fh = figure('keypressfcn',callstr, ...
    'windowstyle','modal',...    
    'position',[0 0 1 1],...
    'Name','GETKEY', ...
    'Visible','Off', ...
    'userdata',999) ; 
try
    % Wait for something to happen
    if wait==0
        uiwait;
    else 
        uiwait(fh,wait);
    end
    ch = get(fh,'Userdata') ;

    if isempty(ch),
        ch = NaN ; 
    end
catch
    % Something went wrong, return and empty matrix.
    ch = [] ;
end

delete(fh) ;