1 %% Copyright (c) 2011, INRA
2 %% 2004-2011, David Legland <david.legland@grignon.inra.fr>
3 %% 2011 Adapted to Octave by Juan Pablo Carbajal <carbajal@ifi.uzh.ch>
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35 %% @deftypefn {Function File} {@var{d} = } edgePosition (@var{point}, @var{edge})
36 %% Return position of a point on an edge
38 %% POS = edgePosition(POINT, EDGE);
39 %% Computes position of point POINT on the edge EDGE, relative to the
40 %% position of edge vertices.
41 %% EDGE has the form [x1 y1 x2 y2],
42 %% POINT has the form [x y], and is assumed to belong to edge.
43 %% The position POS has meaning:
44 %% POS<0: POINT is located before the first vertex
45 %% POS=0: POINT is located on the first vertex
46 %% 0<POS<1: POINT is located between the 2 vertices (on the edge)
47 %% POS=1: POINT is located on the second vertex
48 %% POS<0: POINT is located after the second vertex
50 %% POS = edgePosition(POINT, EDGES);
51 %% If EDGES is an array of NL edges, return NL positions, corresponding to
54 %% POS = edgePosition(POINTS, EDGE);
55 %% If POINTS is an array of NP points, return NP positions, corresponding
58 %% POS = edgePosition(POINTS, EDGES);
59 %% If POINTS is an array of NP points and edgeS is an array of NL edges,
60 %% return an array of [NP NL] position, corresponding to each couple
63 %% @seealso{edges2d, createEdge, onEdge}
66 function d = edgePosition(point, edge)
68 % number of points and of edges
73 dxl = edge(:, 3)-edge(:,1);
74 dyl = edge(:, 4)-edge(:,2);
75 dxp = point(:, 1) - edge(:, 1);
76 dyp = point(:, 2) - edge(:, 2);
78 d = (dxp.*dxl + dyp.*dyl)./(dxl.*dxl+dyl.*dyl);
81 % expand one of the array to have the same size
82 dxl = repmat((edge(:,3)-edge(:,1))', Np, 1);
83 dyl = repmat((edge(:,4)-edge(:,2))', Np, 1);
84 dxp = repmat(point(:,1), 1, Nl) - repmat(edge(:,1)', Np, 1);
85 dyp = repmat(point(:,2), 1, Nl) - repmat(edge(:,2)', Np, 1);
87 d = (dxp.*dxl + dyp.*dyl)./(dxl.*dxl+dyl.*dyl);