function cbg2fig(system_name, ...
                 system_type, full_name, ...
                 stroke_length, stroke_thickness, stroke_colour, ...
                 comp_font, comp_colour_u, comp_colour_o)
% cbg2fig - converts causal bg to figure
%
%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
%     %%%%% Model Transformation Tools %%%%%
%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Matlab function  cbg_m2fig
% Causal bond graph:  mfile format to fig file format
% The resultant fig file is the original _abg.fig with
% additional causal strokes superimposed.
% cbg2fig(system_name, ...
%                  system_type, full_name, ...
%                  stroke_length, stroke_thickness, stroke_colour, ...
%                  comp_font, comp_colour_u, comp_colour_o)
 

% P.J.Gawthrop May 1996
% Copyright (c) P.J.Gawthrop, 1996.

% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% Version control history
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% $Id$
% %% $Log$
% %% Revision 1.7  1997/08/19 09:49:19  peterg
% %% Modified to take account of the expanded vector bonds. Only displays
% %% causality corresponding to the bond connecting the first element of
% %% the vector ports.
% %%
% %% Revision 1.6  1997/08/19 09:41:47  peterg
% %% Some debugging lines added.
% %%
% %% Revision 1.5  1997/05/16  07:33:45  peterg
% %% Now checks to see if sub system is a simple component before
% %% recursion.
% %% 0 --> zero
% %% 1 --> one
% %%
% %% Revision 1.4  1996/12/07  21:34:52  peterg
% %% Tests for null string with strcmp
% %% 
% %% Revision 1.3  1996/08/08  15:52:28  peter
% %% Recursive version.
% %% Fails due to octave bug - reported.
% %%
% %% Revision 1.2  1996/08/05 20:15:39  peter
% %% Prepared for recursive version.
% %%
% %% Revision 1.1  1996/08/05 18:12:25  peter
% %% Initial revision
% %%
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


if nargin<4
  stroke_length = 20;
end;

if nargin<5
  stroke_thickness = 2;
end;

if nargin<6
  stroke_colour = 1; %Blue
end;

if nargin<7
  comp_font = 18; %Helvetica bold
end;

if nargin<8
  comp_colour_u = 12; %Green
end;

if nargin<9
  comp_colour_o = 4; %Red
end;

% Create a back slash '\' character.
bs = setstr(92);

% Create the (full) system name
if strcmp(full_name,'')
  full_name = system_name;
  system_type = system_name;
else
  full_name = [full_name, '_', system_name];
end;

full_name_type = [full_name, '_', system_type];
% $$$ fig_name = [full_name_type, '_cbg.fig'];
fig_name = [full_name, '_cbg.fig']
 
% Return if cbg file doesn't exist
if exist(fig_name)~=2
  return
end;

% Setup file - append to the fig file
filenum = fopen(fig_name, 'a');

% Get the raw and the processed bonds
eval(['[rbonds,rstrokes,rcomponents] = ', system_type, '_rbg;']);
eval(['[bonds,components,n_ports] = ', system_type, '_abg;']);

% Original number of bonds
[n_bonds,junk] = size(rbonds);

% Get the causal bonds
eval(['[cbonds,status]=', full_name, '_cbg;']);

% Check sizes
[N_components,Columns] = size(rcomponents);
if (Columns ~= 13)
  error('Incorrect rcomponents matrix: must have 13 columns');
end;
M_components = Columns;

% Rotation matrix
rot = [0 -1; 1 0];


% Determine coordinates of the arrow end of the bond and the other end
% and other geometry
other_end_1 = rbonds(:,1:2);
arrow_end = rbonds(:,3:4);
other_end_2 = rbonds(:,5:6);

distance_1 = length2d(other_end_1 - arrow_end);
distance_2 = length2d(other_end_2 - arrow_end);
which_end = (distance_1>distance_2)*[1 1];
one = ones(size(which_end));
other_end = which_end.*other_end_1 + (one-which_end).*other_end_2;
arrow_barb = which_end.*other_end_2 + (one-which_end).*other_end_1;
arrow_vector =  arrow_barb-arrow_end;
unit_arrow_vector = arrow_vector./(length2d(arrow_vector)*[1 1]);
bond_vector = (arrow_end - other_end);
unit_bond_vector = bond_vector./(length2d(bond_vector)*[1 1]);
unit_stroke_vector = (rot*unit_bond_vector')';
  
% Get indices of bonds with changed causality -- but ignore the extra bonds
% due to vector bond expansion
changed_e = bonds(1:n_bonds,1)~=cbonds(1:n_bonds,1);
changed_f = bonds(1:n_bonds,2)~=cbonds(1:n_bonds,2);
changed = changed_e|changed_f;
% Don't do port bonds
if n_ports>0
  port_bonds = sort(abs(components(1:n_ports,1)));
  changed(port_bonds) = zeros(n_ports,1);
  changed_e(port_bonds) = zeros(n_ports,1);
  changed_f(port_bonds) = zeros(n_ports,1);
end

index_e  = getindex(changed_e,1)'
index_f  = getindex(changed_f,1)'
index  = getindex(changed,1)';

% Print the new strokes in fig format
if index(1,1)>0
  for i = index_e % Do the effort stroke - opp. side to arrow

    if cbonds(i,1)==1 % Stroke at arrow end
      stroke_end_1 = arrow_end(i,:);
    else
      stroke_end_1 = other_end(i,:);
    end;
    
    sig = sign(unit_arrow_vector(i,:)*unit_stroke_vector(i,:)');
    stroke_end_2 = stroke_end_1 - stroke_length*sig*unit_stroke_vector(i,:);
    

    %print the fig3 format firstline spec.
    polyline = 2; 
    firstline = fig3(polyline,stroke_thickness,stroke_colour);
    fprintf(filenum, '%s\n', firstline);

    fprintf(filenum, '	%4.0f %4.0f %4.0f %4.0f \n', ...
	stroke_end_1(1), stroke_end_1(2), ...
	stroke_end_2(1), stroke_end_2(2) );
  end;

  for i = index_f % Do the flow stroke - same side as arrow

    if cbonds(i,2)==1 % Stroke at arrow end
      stroke_end_1 = arrow_end(i,:);
    else
      stroke_end_1 = other_end(i,:);
    end;
    
    sig = sign(unit_arrow_vector(i,:)*unit_stroke_vector(i,:)');
    stroke_end_2 = stroke_end_1 + stroke_length*sig*unit_stroke_vector(i,:);
    

    %print the fig3 format firstline spec.
    polyline = 2; 
    firstline = fig3(polyline,stroke_thickness,stroke_colour);
    fprintf(filenum, '%s\n', firstline);

    fprintf(filenum, '	%4.0f %4.0f %4.0f %4.0f \n', ...
	stroke_end_1(1), stroke_end_1(2), ...
	stroke_end_2(1), stroke_end_2(2) );
  end;
end;

% Print all the components - coloured acording to causality.
for i = 1:N_components
  fig_params = rcomponents(i,3:M_components);
  coords = rcomponents(i,1:2);
  
  if status(i)==-1  %Then under causal
    fig_params(3) = comp_colour_u;
    fig_params(6) = comp_font;
  end;

  if status(i)==1  %Then over causal
    fig_params(3) = comp_colour_o;
    fig_params(6) = comp_font;
  end;


  %Now print the component in fig format
  eval(['[comp_type,comp_name] = ', system_type, '_cmp(i);']);

  Terminator = [bs, '001'];   
  for j = 1:length(fig_params)
    fprintf(filenum, '%1.0f ', fig_params(j));
  end;
  fprintf(filenum, '%1.0f %1.0f ', coords(1), coords(2)); 
  fprintf(filenum, '%s:%s%s\n', comp_type, comp_name, Terminator);
  
  % If it's a subsystem (ie not a component), do the fig file for that as
  % well
  if comp_type=='0'
    comp_type='zero';
  end
  if comp_type=='1'
    comp_type='one';
  end
  
  if (exist([comp_type,'_cause'])==0)
    cbg2fig(comp_name, ...
	comp_type, full_name, ...
        stroke_length, stroke_thickness, stroke_colour, ...
        comp_font, comp_colour_u, comp_colour_o);
  end;
	   
end;

% Close the file
fclose(filenum);
return