transformEdge

TRANSFORMEDGE Transform an edge with an affine transform.

   EDGE2 = transformEdge(EDGE1, TRANS);
   where EDGE1 has the form [x1 y1 x2 y1], and TRANS is a transformation
   matrix, return the edge transformed with affine transform TRANS. 

   Format of TRANS can be one of :
   [a b]   ,   [a b c] , or [a b c]
   [d e]       [d e f]      [d e f]
                            [0 0 1]

   EDGE2 = transformEdge(EDGES, TRANS); 
   Also wotk when EDGES is a [N*4] array of double. In this case, EDGE2
   has the same size as EDGE. 

   See also
   edges2d, transforms2d, transformPoint, translation, rotation

0001 function dest = transformEdge(edge, trans)
0002 %TRANSFORMEDGE Transform an edge with an affine transform.
0003 %
0004 %   EDGE2 = transformEdge(EDGE1, TRANS);
0005 %   where EDGE1 has the form [x1 y1 x2 y1], and TRANS is a transformation
0006 %   matrix, return the edge transformed with affine transform TRANS.
0007 %
0008 %   Format of TRANS can be one of :
0009 %   [a b]   ,   [a b c] , or [a b c]
0010 %   [d e]       [d e f]      [d e f]
0011 %                            [0 0 1]
0012 %
0013 %   EDGE2 = transformEdge(EDGES, TRANS);
0014 %   Also wotk when EDGES is a [N*4] array of double. In this case, EDGE2
0015 %   has the same size as EDGE.
0016 %
0017 %   See also
0018 %   edges2d, transforms2d, transformPoint, translation, rotation
0019 
0020 % ------
0021 % Author: David Legland
0022 % E-mail: david.legland@inrae.fr
0023 % Created: 2004-04-06
0024 % Copyright 2004-2024 INRA - TPV URPOI - BIA IMASTE
0025 
0026 % allocate memory
0027 dest = zeros(size(edge));
0028 
0029 % compute position
0030 for i=1:2
0031   T           = trans(i,1:2).';
0032   dest(:,i)   = edge(:,1:2) * T;
0033   dest(:,i+2) = edge(:,3:4) * T;
0034 end
0035 
0036 % add translation vector, if exist
0037 if size(trans, 2) > 2
0038   dest = bsxfun (@plus, dest, trans([1:2 1:2],3).');
0039 end
0040