samer@4: function iterate_gui(stfn,S0,varargin)
samer@4: % iterate_gui - iterate state transformer under GUI control
samer@4: %
samer@4: % iterate_gui :: 
samer@4: %    (A->A,handle)   ~'state transformer function',
samer@4: %    A               ~'initial state'
samer@4: % -> gui.
samer@4: %
samer@4: % The idea is that the state transformer returns a handle to a
samer@4: % GUI element to be used for advancing the sequence. You click
samer@4: % on that element to move to the next element of the sequence.
samer@4: % Button 2 rewinds to the beginning of the sequence.
samer@4: 
samer@4: % to do: user configurable keys to allow multiple plotseqs
samer@4: % in same figure, each watching different keys.
samer@4: 
samer@37: 	opts=options('keyctl','set',varargin{:});
samer@4: 
samer@4: 	[S,h]=stfn(S0);
samer@4: 	set(h,'ButtonDownFcn',@btndn);
samer@4: 	switch opts.keyctl
samer@4: 		case 'set', addkbcallback(gcf), addkbcallback(gcf,@keypress);
samer@4: 		case 'add', addkbcallback(gcf,@keypress);
samer@4: 	end
samer@4: 
samer@4: 	function next()
samer@4: 		if isempty(S), beep; 
samer@4: 		else 
samer@4: 			[S,h]=stfn(S); 
samer@4: 			set(h,'ButtonDownFcn',@btndn);
samer@4: 		end
samer@4: 	end
samer@4: 
samer@4: 	function rewind(), [S,h]=stfn(S0); set(h,'ButtonDownFcn',@btndn); end
samer@4: 	function btndn(a,b)
samer@4: 		if strcmp(get(gcf,'SelectionType'),'alt'), rewind();
samer@4: 		else next(); end
samer@4: 	end
samer@4: 
samer@4: 	function keypress(b)
samer@4: 		switch b.Character
samer@4: 			case {'b','r'}, rewind();
samer@4: 			case {' ','n'}, next();
samer@4: 		end
samer@4: 	end
samer@4: end % of main function
samer@4: