## -*-octave-*-
function [bonds] = \
rbg2ibg(name,rbonds,rstrokes,rcomponents,port_coord,port_name, \
infofile, errorfile)
rbonds
rstrokes
rcomponents
port_coord
port_name
## Default to no components
components = [0];
## Xfig scaling factor
scale = 1200.0/2.54546;
## Rotation matrix
rot = [0, -1; 1, 0];
## Find number of strokes
[n_strokes,columns] = size(rstrokes);
if ((columns ~= 4) & (n_strokes > 0))
error('Incorrect rstrokes matrix: must have 4 columns');
endif
## Find number of bonds
[n_bonds,columns] = size(rbonds);
if ((columns ~= 6) & (n_bonds > 0))
error('Incorrect rbonds matrix: must have 6 columns');
endif
## Find number of components
[n_components,columns] = size(rcomponents);
## Find number of ports referred to
[n_ports,columns] = size(port_coord);
## If port_name empty, make it empty string
if (length(port_name) == 0)
port_name="";
endif
## Determine coordinates of arrow end of bond and other end
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_vector = (which_end .* other_end_2 + (one - which_end) .* \
other_end_1) - arrow_end;
## Locate bond end nearest each port
## col 1 of port_near_bond contains a signed bond number (+ for arrow
## end)
## col 2 of port_near_bond contains the corresponding port index
port_bond = [];
for i = 1:n_ports
near_bond = adjbond(port_coord(i,1:2), arrow_end, other_end);
[rows,cols] = size(near_bond);
if (rows > 1)
error(sprintf ...
("A port is near to more than one bond at coordinates \
%g,%g %s\n", ...
port_coord(i,1)/scale, port_coord(i,2)/scale, \
deblank(port_name(i,:))));
endif
## The (signed) bond corresponding to the ith port label
port_bond(i) = near_bond(1) * sign(1.5 - near_bond(2));
endfor
port_bond
## Now have (signed) bond (port_bond(i)) corresponding to the ith port
## Create inverse mapping
for i = 1:n_bonds
eval(sprintf('bond_port_head%i = "[]"', i))
eval(sprintf('bond_port_tail%i = "[]"', i))
endfor
for i = 1:n_ports
if (port_bond(i) > 0)
eval(sprintf('bond_port_head%i = "%s"', port_bond(i), \
deblank(port_name(i,:))))
else
eval(sprintf('bond_port_tail%i = "%s"', -port_bond(i), \
deblank(port_name(i,:))))
endif
endfor
## Locate the components at the ends of each bond
## col 1 of comp_near_bond contains component nearest to the arrow end
## col 2 of comp_near_bond contains component nearest other end
for i = 1:n_bonds
comp_near_bond(i,:) = adjcomp(arrow_end(i,:), other_end(i,:), \
rcomponents);
[hc_type, hc_name] = eval([name, '_cmp(comp_near_bond(i,1))']);
[tc_type, tc_name] = eval([name, '_cmp(comp_near_bond(i,2))']);
endfor
## Deduce causality from the strokes (if any)
causality = zeros(n_bonds,2);
if (n_strokes > 0)
## Find location of centre and ends of stroke
stroke_end_1 = [rstrokes(:,1), rstrokes(:,2)];
stroke_end_2 = [rstrokes(:,3), rstrokes(:,4)];
stroke_centre = (stroke_end_1 + stroke_end_2)/2;
stroke_vector = (stroke_end_1 - stroke_end_2);
stroke_length = length2d(stroke_vector);
for i = 1:n_strokes
stroke = [stroke_centre(i,:)
stroke_end_1(i,:)
stroke_end_2(i,:)];
## Find the nearest bond end
[index,distance] = adjbond(stroke(1,:),arrow_end,other_end);
if (distance > (2 * stroke_length(i)))
info = sprintf('Stroke at (%4.3f,%4.3f) is %4.3f away from the nearest bond\n', ...
stroke(1,1)/scale, stroke(1,2)/scale, \
distance/scale);
endif
## Bond end coordinates
j = index(1,1);
which_end = (index(1,2) == 1);
bond_end = arrow_end(j,:) * which_end + other_end(j,:) * (1 - \
which_end);
## Now decide which bit of the stroke is nearest
stroke_index = adjbond(bond_end, stroke, zeros(size(stroke)));
if (stroke_index(1) == 1) # uni-causal stroke
causality(j,1:2) = (2 * which_end - 1) * [1, 1];
else # bi-causal stroke
stroke_direction = stroke(1,:) - stroke(stroke_index(1),:);
flow_side = stroke_direction * arrow_vector(j,:)' > 0;
causality(j,1+flow_side) = 2 * which_end - 1;
endif
endfor
endif
## Return data
for i = 1:n_bonds
eval(sprintf("bonds.bond%i.head.component\t= '%s:%s'", i, hc_type, \
hc_name));
eval(sprintf("bonds.bond%i.tail.component\t= '%s:%s'", i, tc_type, \
tc_name));
eval(sprintf("bonds.bond%i.head.ports\t= bond_port_head%i", i, i));
eval(sprintf("bonds.bond%i.tail.ports\t= bond_port_tail%i", i, i));
endfor
endfunction