--- /dev/null
+%% Copyright (c) 2011, INRA
+%% 2003-2011, David Legland <david.legland@grignon.inra.fr>
+%% 2011 Adapted to Octave by Juan Pablo Carbajal <carbajal@ifi.uzh.ch>
+%%
+%% All rights reserved.
+%% (simplified BSD License)
+%%
+%% Redistribution and use in source and binary forms, with or without
+%% modification, are permitted provided that the following conditions are met:
+%%
+%% 1. Redistributions of source code must retain the above copyright notice, this
+%% list of conditions and the following disclaimer.
+%%
+%% 2. Redistributions in binary form must reproduce the above copyright notice,
+%% this list of conditions and the following disclaimer in the documentation
+%% and/or other materials provided with the distribution.
+%%
+%% THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+%% AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+%% IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+%% ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+%% LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+%% CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+%% SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+%% INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+%% CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+%% ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+%% POSSIBILITY OF SUCH DAMAGE.
+%%
+%% The views and conclusions contained in the software and documentation are
+%% those of the authors and should not be interpreted as representing official
+%% policies, either expressed or implied, of copyright holder.
+
+%% -*- texinfo -*-
+%% @deftypefn {Function File} {@var{edge} = } createEdge (@var{p1}, @var{p2})
+%% @deftypefnx {Function File} {@var{edge} = } createEdge (@var{x0}, @var{y0}, @var{dx}, @var{dy})
+%% @deftypefnx {Function File} {@var{edge} = } createEdge (@var{param})
+%% @deftypefnx {Function File} {@var{edge} = } createEdge (@var{line}, @var{d})
+%% Create an edge between two points, or from a line.
+%%
+%% The internal format for edge representation is given by coordinates of
+%% two points : [x1 y1 x2 y2].
+%% This function can serve as a line to edge converter.
+%%
+%%
+%% Returns the edge between the two given points @var{p1} and @var{p2}.
+%%
+%% Returns the edge going through point (@var{x0}, @var{y0}) and with direction
+%% vector (@var{dx},@var{dy}).
+%%
+%% When @var{param} is an array of 4 values, creates the edge going through the
+%% point (param(1) param(2)), and with direction vector given by
+%% (param(3) param(4)).
+%%
+%% When @var{line} is given, creates the edge contained in @var{line}, with same
+%% direction and start point, but with length given by @var{d}.
+%%
+%%
+%% Note: in all cases, parameters can be vertical arrays of the same
+%% dimension. The result is then an array of edges, of dimensions [N*4].
+%%
+%% @seealso{edges2d, lines2d, drawEdge, clipEdge}
+%% @end deftypefn
+
+function edge = createEdge(varargin)
+
+ if length(varargin)==1
+ % Only one input parameter. It can be :
+ % - line angle
+ % - array of four parameters
+ % TODO : add control for arrays of lines.
+ var = varargin{1};
+
+ if size(var, 2)==4
+ % 4 parameters of the line in a single array.
+ %edge = var;
+ edge = zeros(size(var));
+ edge(:, 1:2) = var(:,1:2);
+ edge(:, 3:4) = edge(:, 1:2)+var(:,3:4);
+ elseif size(var, 2)==1
+ % 1 parameter : angle of the line, going through origin.
+ edge = [zeros(size(var,1)) zeros(size(var,1)) cos(var) sin(var)];
+ else
+ error('wrong number of dimension for arg1 : can be 1 or 4');
+ end
+
+ elseif length(varargin)==2
+ % 2 input parameters. They can be :
+ % - 2 points, then 2 arrays of 1*2 double,
+ % - a line, and a distance.
+ v1 = varargin{1};
+ v2 = varargin{2};
+ if size(v1, 2)==2
+ % first input parameter is first point, and second input is the
+ % second point.
+ %edge = [v1(:,1), v1(:,2), v2(:,1), v2(:,2)];
+ edge = [v1 v2];
+ else
+ % first input parameter is a line, and second one a distance.
+ angle = atan2(v1(:,4), v1(:,3));
+ edge = [v1(:,1), v1(:,2), v1(:,1)+v2.*cos(angle), v1(:,2)+v2.*sin(angle)];
+ end
+
+ elseif length(varargin)==3
+ % 3 input parameters :
+ % first one is a point belonging to the line,
+ % second and third ones are direction vector of the line (dx and dy).
+ p = varargin{1};
+ edge = [p(:,1) p(:,2) p(:,1)+varargin{2} p(:,2)+varargin{3}];
+
+ elseif length(varargin)==4
+ % 4 input parameters :
+ % they are x0, y0 (point belonging to line) and dx, dy (direction
+ % vector of the line).
+ % All parameters should have the same size.
+ edge = [varargin{1} varargin{2} varargin{1}+varargin{3} varargin{2}+varargin{4}];
+ else
+ error('Wrong number of arguments in ''createLine'' ');
+ end
+
+endfunction