plotedges

 hm=plotedges(node,edges,opt)
   or
 hm=plotedges(node,loops,opt)

 plot a 3D polyline or close loop (1d manifold)
 
 author: Qianqian Fang <fangq at nmr.mgh.harvard.edu>

 input: 
      node: node coordinates, dimension (nn,3); if node has a 
            4th column, it will be used to set the color at each node.
      edges:edge list: a 2-column index array, with each row being
            an edge connecting the two indexed node
      loops:loops is an NaN separated integer array, with each segment
            denoting a 3D polyline or loop represented by a list of node
            indices
      opt:  additional options for the plotting, see plotmesh

 output:
      hm: handle or handles (vector) to the plotted surfaces

 example:

   h=plotedges(node,[1 2 3 4 5 nan 6 7 8 9]);
   h=plotedges(node,edges,'marker','o','linewidth',2,'color','r');
 
 -- this function is part of iso2mesh toolbox (http://iso2mesh.sf.net)

0001 function hh=plotedges(node,edges,varargin)
0002 %
0003 % hm=plotedges(node,edges,opt)
0004 %   or
0005 % hm=plotedges(node,loops,opt)
0006 %
0007 % plot a 3D polyline or close loop (1d manifold)
0008 %
0009 % author: Qianqian Fang <fangq at nmr.mgh.harvard.edu>
0010 %
0011 % input:
0012 %      node: node coordinates, dimension (nn,3); if node has a
0013 %            4th column, it will be used to set the color at each node.
0014 %      edges:edge list: a 2-column index array, with each row being
0015 %            an edge connecting the two indexed node
0016 %      loops:loops is an NaN separated integer array, with each segment
0017 %            denoting a 3D polyline or loop represented by a list of node
0018 %            indices
0019 %      opt:  additional options for the plotting, see plotmesh
0020 %
0021 % output:
0022 %      hm: handle or handles (vector) to the plotted surfaces
0023 %
0024 % example:
0025 %
0026 %   h=plotedges(node,[1 2 3 4 5 nan 6 7 8 9]);
0027 %   h=plotedges(node,edges,'marker','o','linewidth',2,'color','r');
0028 %
0029 % -- this function is part of iso2mesh toolbox (http://iso2mesh.sf.net)
0030 %
0031 
0032 edlen=size(edges,1);
0033 hh=[];
0034 if(isempty(edges))
0035     return;
0036 end
0037 
0038 rngstate = rand ('state');
0039 
0040 if(size(edges,1)==1 || size(edges,2)==1) % a loop: single column/row edges
0041     randseed=hex2dec('623F9A9E'); % "U+623F U+9A9E"
0042     if(isoctavemesh) randseed=randseed+3; end
0043     if(~isempty(getvarfrom({'caller','base'},'ISO2MESH_RANDSEED')))
0044         randseed=getvarfrom({'caller','base'},'ISO2MESH_RANDSEED');
0045     end
0046     rand('state',randseed);
0047 
0048     loops=edges(:)';
0049     if(~isnan(loops(end)))
0050         loops(end+1)=nan;
0051     end
0052     seg=find(isnan(loops));
0053     seglen=length(seg);
0054     seghead=1;
0055     for i=1:seglen
0056         h=plotmesh(node(loops(seghead:seg(i)-1),:), 'color',rand(3,1), varargin{:});
0057         hh=[hh h];
0058         seghead=seg(i)+1;
0059     end
0060 else  % an edge list
0061  if(size(node,2)==2) % 2D polyline
0062     for i=1:edlen
0063        h = line([node(edges(i,1),1) node(edges(i,2),1)],[node(edges(i,1),2) node(edges(i,2),2)], varargin{:});
0064        hh=[hh,h];
0065     end
0066  else  % 3D polyline
0067     for i=1:edlen
0068        h = line([node(edges(i,1),1) node(edges(i,2),1)],[node(edges(i,1),2) ...
0069               node(edges(i,2),2)],[node(edges(i,1),3) node(edges(i,2),3)], varargin{:});
0070        hh=[hh,h];
0071     end
0072  end
0073 end
0074 
0075 rand ('state',rngstate);