function out = gwi( arg, arg2)
% gwi: a grid world interface

global alpha beta gamma delta lambda
global gt ge gs bt be bs at ae as stop
global fx fy fm ff

if( nargin < 1)
	gwi( 'new');
	return;
end

% call backs
switch( arg)
case 'new'
	gw( 'new');
	%gamma = 1; beta = 5; alpha = 0.5;
	ff = figure(4);	% focus
	f3 = get(3,'Position');
	set(ff,'Position',[f3(1),f3(2)-fm(3)-fm(4)-200,400,200],'Name','Command');
	clf;
	% buttons
	uicontrol(ff,'Style','pushbutton','Position',[20,140,90,40],...
		'Callback','gwi new','String','New','FontSize',24);
	uicontrol(ff,'Style','pushbutton','Position',[120,140,90,40],...
		'Callback','gw try','String','Try','FontSize',24);
	uicontrol(ff,'Style','pushbutton','Position',[220,140,90,40],...
		'Callback','gw 10 try','String','Repeat','FontSize',24);
	uicontrol(ff,'Style','pushbutton','Position',[320,140,90,40],...
		'Callback','gw stop','String','Stop','FontSize',24);
	% gamma
	gt = uicontrol(ff,'Style','text','Position',[20,90,100,40],...
		'String','Gamma','FontSize',24);
	ge = uicontrol(ff,'Style','edit','Position',[120,90,80,40],...
		'Callback','gwi gedit',...
		'String',num2str(gamma),'FontSize',24);
	gs = uicontrol(ff,'Style','slider','Position',[200,90,200,40],...
		'Callback','gwi gslide',...
		'Min',0,'Max',1,'SliderStep',[0.01,0.1],'Value',gamma);
	% beta
	bt = uicontrol(ff,'Style','text','Position',[20,50,100,40],...
		'String','Beta','FontSize',24);
	be = uicontrol(ff,'Style','edit','Position',[120,50,80,40],...
		'Callback','gwi bedit',...
		'String',num2str(beta),'FontSize',24);
	bs = uicontrol(ff,'Style','slider','Position',[200,50,200,40],...
		'Callback','gwi bslide',...
		'Min',0,'Max',10,'SliderStep',[0.01,0.1],'Value',beta);
	% alpha
	at = uicontrol(ff,'Style','text','Position',[20,10,100,40],...
		'String','Alpha','FontSize',24);
	ae = uicontrol(ff,'Style','edit','Position',[120,10,80,40],...
		'Callback','gwi aedit',...
		'String',num2str(alpha),'FontSize',24);
	as = uicontrol(ff,'Style','slider','Position',[200,10,200,40],...
		'Callback','gwi aslide',...
		'Min',0,'Max',1,'SliderStep',[0.01,0.1],'Value',alpha);
% gamma
case 'gedit'
	g = str2num( get(gcbo,'string'));
	if isempty(g), break; end
	gamma = max( 0, min( 1, g))
	set(gs,'Value',gamma);
case 'gslide'
	gamma = get(gcbo,'Value');
	set(ge,'string',num2str(gamma));
	gamma
% beta
case 'bedit'
	b = str2num( get(gcbo,'string'));
	if isempty(b), break; end
	beta = max( 0, min( 10, b))
	set(bs,'Value',beta);
case 'bslide'
	beta = get(gcbo,'Value');
	set(be,'string',num2str(beta));
	beta
% alpha
case 'aedit'
	a = str2num( get(gcbo,'string'));
	if isempty(a), break; end
	alpha = max( 0, min( 1, a))
	set(as,'Value',alpha);
case 'aslide'
	alpha = get(gcbo,'Value');
	set(ae,'string',num2str(alpha));
	alpha
end