function RGB=definergb(rgb, default)
%DEFINERGB  User Graphical Interface to define any RGB color.
%
%       RGB = DEFINERGB(rgb)
% 
%       Open a new figure and by mean of four slide controls
%       allows to define any color in the RGB mode.
%       The fourth slide control increase or decrease the brigthness.
%
%       rgb      is the starting color vector, black ([0 0 0]) if omitted.
%       RGB     is the vector of the three R, G, B values defining a color.
%
%       OK           return the specified color.
%       CANCEL   return the original color (rgb).
%                   
%
%       Claudio  7 Feb, 1995. 
%	modified by M. Young 14 Feb, 1995 to put in a color palette to choose a starting color
%

%
% Copyright (c) 1995 by Claudio Rivetti and Mark Young
% claudio@alice.uoregon.edu,    mark@alice.uoregon.edu
%

gvar='global Rsl Gsl Bsl Lsl Rvl Gvl Bvl RGBfr RGBtx df;';
global AlexDir Uibgcolor
eval(gvar)


if nargin <1, rgb=[0 0 0];end
if nargin >2, error('Too many input arguments.');end
if nargin ==1
  df=rgb;
else
  df=default;
end
if length(rgb) ~= 3, error('The argument must be a vector of R, G, B values.');end
if find(rgb>1 == 1)  |  find(RGB<0 == 1), error('R, G, B values must be between 0 and 1.');end 

Bg=Uibgcolor;
RGB=rgb;
Figpos=[400 600 600 250];

Rtxpos=[50 200 75 20];
Gtxpos=[50 160 75 20];
Btxpos=[50 120 75 20];
Ltxpos=[20  80 100 20];

Rslpos=[130 200 250 20];
Gslpos=[130 160 250 20];
Bslpos=[130 120 250 20];
Lslpos=[130  80 250 20];

Rvlpos=[390 200 75 20];
Gvlpos=[390 160 75 20];
Bvlpos=[390 120 75 20];

RGBfrpos=[470 110 110 115];
RGBtxpos=[470 87 110 20];

DFbtpos=[250 20 80 40];
OKbtpos=[405 20 80 40];
CANCELbtpos=[505 20 80 40];


DFcbk=[gvar  'set(Rsl, ''value'', df(1));set(Rvl, ''string'', num2str(df(1)));',...
	     'set(Gsl, ''value'', df(2));set(Gvl, ''string'', num2str(df(2)));',...
	     'set(Bsl, ''value'', df(3));set(Bvl, ''string'', num2str(df(3)));',...
	     'set(Lsl, ''value'', 0);',...
	     'set(Lsl, ''min'',(-1*max([get(Rsl, ''value'')  get(Gsl, ''value'')  get(Bsl, ''value'')])));',...
	     'set(Lsl, ''max'',(1-min([get(Rsl, ''value'')  get(Gsl, ''value'')  get(Bsl, ''value'')])));',...
	     'set(RGBfr, ''Background'', [get(Rsl, ''value'')  get(Gsl, ''value'')  get(Bsl, ''value'')]);'];


StartPalettePos=[30 203];

PaletteFrameSize = [20 20];

letters='ABCDEFGHILM';
numbers='12345678';


%%%%%%%%%%  MAKE FIGURE  %%%%%%%%%%%%

fig=figure('Position', Figpos, 'Resize', 'Off', 'Color', Bg, 'NumberTitle', 'off', 'Name', 'RGB Definition', 'nextplot', 'new','Interruptible', 'yes');


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%			Now begins Claudio's section - buttons and sliders
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%  TEXT   %%%%%%%%%%%

uicontrol(fig, 'Style', 'text',...
                'String', 'Red',...
                'Units', 'pixels',...
                'Position', Rtxpos,...
                'BackgroundColor', Bg,...
                'HorizontalAlignment', 'right');

uicontrol(fig, 'Style', 'text',...
                'String', 'Green',...
                'Units', 'pixels',...
                'Position', Gtxpos,...
                'BackgroundColor', Bg,...
                'HorizontalAlignment', 'right');

uicontrol(fig, 'Style', 'text',...
                'String', 'Blue',...
                'Units', 'pixels',...
                'Position', Btxpos,...
                'BackgroundColor', Bg,...
                'HorizontalAlignment', 'right');

uicontrol(fig, 'Style', 'text',...
                'String', 'Brightness',...
                'Units', 'pixels',...
                'Position', Ltxpos,...
                'BackgroundColor', Bg,...
                'HorizontalAlignment', 'right');


%%%%%%%%%%%%  SLIDES  %%%%%%%%%%%%%

Rsl=uicontrol(fig, 'Style', 'slider',...
                'Units', 'pixels',...
                'position', Rslpos,...
                'Background', 'red',...
                'Min', 0,...
                'Max', 1,...
                'Value', rgb(1),...
                'CallBack', ['global Rsl Gsl Bsl Lsl Rvl Gvl Bvl RGBfr RGBtx;set(Rvl, ''string'',  num2str(get(Rsl, ''value'')) );',...
				  'set(RGBtx, ''string'', '' '');',...
                                  'set(Lsl, ''Min'', -1*max([get(Rsl, ''value'')  get(Gsl, ''value'')  get(Bsl, ''value'')])  );',...
                                  'set(Lsl, ''Max'', 1-min([get(Rsl, ''value'')  get(Gsl, ''value'')  get(Bsl, ''value'')])  );',...
                                  'set(Lsl, ''Value'', 0 , ''Userdata'', 0 );',...
                                  'set(RGBfr, ''Background'', [get(Rsl, ''value'')  get(Gsl, ''value'')  get(Bsl, ''value'')]);']);

Gsl=uicontrol(fig, 'Style', 'slider',...
                'Units', 'pixels',...
                'position', Gslpos,...
                'Background', 'green',...
                'Min', 0,...
                'Max', 1,...
                'Value', rgb(2),...
                'CallBack', ['global Rsl Gsl Bsl Lsl Rvl Gvl Bvl RGBfr RGBtx;set(Gvl, ''string'',  num2str(get(Gsl, ''value'')) );',...
				  'set(RGBtx, ''string'', '' '');',...
                                  'set(Lsl, ''Min'', -1*max([get(Rsl, ''value'')  get(Gsl, ''value'')  get(Bsl, ''value'')])  );',...
                                  'set(Lsl, ''Max'', 1-min([get(Rsl, ''value'')  get(Gsl, ''value'')  get(Bsl, ''value'')])  );',...
                                  'set(Lsl, ''Value'', 0 , ''Userdata'', 0 );',...
                                  'set(RGBfr, ''Background'', [get(Rsl, ''value'')  get(Gsl, ''value'')  get(Bsl, ''value'')]);']);

Bsl=uicontrol(fig, 'Style', 'slider',...
                'Units', 'pixels',...
                'position', Bslpos,...
                'Background', 'blue',...
                'Min', 0,...
                'Max', 1,...
                'Value', rgb(3),...
                'CallBack', ['global Rsl Gsl Bsl Lsl Rvl Gvl Bvl RGBfr RGBtx;set(Bvl, ''string'',  num2str(get(Bsl, ''value'')) );',...
				  'set(RGBtx, ''string'', '' '');',...
                                  'set(Lsl, ''Min'', -1*max([get(Rsl, ''value'')  get(Gsl, ''value'')  get(Bsl, ''value'')])  );',...
                                  'set(Lsl, ''Max'', 1-min([get(Rsl, ''value'')  get(Gsl, ''value'')  get(Bsl, ''value'')])  );',...
                                  'set(Lsl, ''Value'', 0 , ''Userdata'', 0);',...
                                  'set(RGBfr, ''Background'', [get(Rsl, ''value'')  get(Gsl, ''value'')  get(Bsl, ''value'')]);']);


Lsl=uicontrol(fig, 'Style', 'slider',...
                'Units', 'pixels',...
                'position', Lslpos,...
                'Background', Bg,...
                'Min', (-1*max([get(Rsl, 'value')  get(Gsl, 'value')  get(Bsl, 'value')])),...
                'Max', (1-min([get(Rsl, 'value')  get(Gsl, 'value')  get(Bsl, 'value')])),...
                'Value',  0,...
		'Userdata', 0,...
                'CallBack', ['global Rsl Gsl Bsl Lsl Rvl Gvl Bvl RGBfr RGBtx;',...
				  'val=(get(Rsl, ''value'') + get(Lsl, ''value'') - get(Lsl, ''Userdata''));',...
				  'if val > 1, val=1;end; if val < 0, val=0;end;',... 
				  'set(Rsl, ''value'',  val);',...
				  'val=get(Gsl, ''value'') + get(Lsl, ''value'') - get(Lsl, ''Userdata'');',...
				  'if val > 1, val=1;end; if val < 0, val=0;end;',... 
                                  'set(Gsl, ''value'',  val);',...
				  'val=get(Bsl, ''value'') + get(Lsl, ''value'') - get(Lsl, ''Userdata'');',...
				  'if val > 1, val=1;end; if val < 0, val=0;end;',... 
                                  'set(Bsl, ''value'',  val);',...
				  'set(Lsl, ''Userdata'', get(Lsl, ''value''));',...
                                  'set(Rvl, ''string'',  num2str(get(Rsl, ''value'')) );',...
                                  'set(Gvl, ''string'',  num2str(get(Gsl, ''value'')) );',...
                                  'set(Bvl, ''string'',  num2str(get(Bsl, ''value'')) );',...
				  'set(RGBtx, ''string'', '' '');',...
                                  'set(RGBfr, ''Background'', [get(Rsl, ''value'')  get(Gsl, ''value'')  get(Bsl, ''value'')]);']);


%%%%%%%%%%%%  VALUES  %%%%%%%%%%%%%%%%%%

Rvl=uicontrol(fig, 'Style', 'text',...
                'String',  num2str(get(Rsl, 'value')),...
                'Units', 'pixels',...
                'Position', Rvlpos,...
                'BackgroundColor', Bg,...
                'HorizontalAlignment', 'left');

Gvl=uicontrol(fig, 'Style', 'text',...
                'String',  num2str(get(Gsl, 'value')),...
                'Units', 'pixels',...
		 'Position', Gvlpos,...
                'BackgroundColor', Bg,...
                'HorizontalAlignment', 'left');

Bvl=uicontrol(fig, 'Style', 'text',...
                'String',  num2str(get(Bsl, 'value')),...
                'Units', 'pixels',...
                'Position', Bvlpos,...
                'BackgroundColor', Bg,...
                'HorizontalAlignment', 'left');



%%%%%%%%%%  RGB  FRAME  %%%%%%%%%%%%


RGBfr = uicontrol(fig, 'Style', 'frame',...
                'Units', 'pixels',...
                'Position', RGBfrpos,...
                'BackgroundColor', [get(Rsl, 'value')  get(Gsl, 'value')  get(Bsl, 'value')]);

RGBtx=uicontrol(fig, 'Style', 'text',...
                'Units', 'pixels',...
                'Position', RGBtxpos,...
                'BackgroundColor', Bg,...
                'HorizontalAlignment', 'center');

%%%%%%%%%  OK - CANCEL  %%%%%%%%%%%%%


DFbt=uicontrol(fig, 'Style', 'push',...
                'String', 'Default',...
                'Units', 'pixels',...
		'Interruptible','yes',...
		'CallBack', DFcbk,...
                'Position', DFbtpos);


OKbt=uicontrol(fig, 'Style', 'push',...
                'String', 'OK',...
                'Units', 'pixels',...
		'Interruptible','yes',...
                'Position', OKbtpos);

CANCELbt=uicontrol(fig, 'Style', 'push',...
                'String', 'Cancel',...
                'Units', 'pixels',...
		'Interruptible','yes',...
                'Position', CANCELbtpos);

pbs=[OKbt CANCELbt];

while ~any(get(fig,'CurrentO')==pbs), 
  drawnow
end

if get(fig,'CurrentO')== OKbt, RGB=[get(Rsl, 'value')  get(Gsl, 'value')  get(Bsl, 'value')];end 
close(fig);
return;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%