--- /dev/null
+%% Copyright (c) 2011, INRA
+%% 2004-2011, 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 PUR@var{pos}E
+%% 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
+%% @var{pos}SIBILITY 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{pos} =} linePosition (@var{point}, @var{line})
+%% Position of a point on a line.
+%%
+%% Computes position of point @var{point} on the line @var{line}, relative to origin
+%% point and direction vector of the line.
+%% @var{line} has the form [x0 y0 dx dy],
+%% @var{point} has the form [x y], and is assumed to belong to line.
+%%
+%% If @var{line} is an array of NL lines, return NL positions, corresponding to
+%% each line.
+%%
+%% If @var{point} is an array of NP points, return NP positions, corresponding
+%% to each point.
+%%
+%% If @var{point} is an array of NP points and @var{line}S is an array of NL lines,
+%% return an array of [NP NL] position, corresponding to each couple
+%% point-line.
+%%
+%% Example
+%%
+%% @example
+%% line = createLine([10 30], [30 90]);
+%% linePosition([20 60], line)
+%% ans =
+%% .5
+%% @end example
+%%
+%% @seealso{lines2d, createLine, projPointOnLine, isPointOnLine}
+%% @end deftypefn
+
+function d = linePosition(point, lin)
+
+ % number of inputs
+ Nl = size(lin, 1);
+ Np = size(point, 1);
+
+ if Np == Nl
+ % if both inputs have the same size, no problem
+ dxl = lin(:, 3);
+ dyl = lin(:, 4);
+ dxp = point(:, 1) - lin(:, 1);
+ dyp = point(:, 2) - lin(:, 2);
+
+ elseif Np == 1
+ % one point, several lines
+ dxl = lin(:, 3);
+ dyl = lin(:, 4);
+ dxp = point(ones(Nl, 1), 1) - lin(:, 1);
+ dyp = point(ones(Nl, 1), 2) - lin(:, 2);
+
+ elseif Nl == 1
+ % one lin, several points
+ dxl = lin(ones(Np, 1), 3);
+ dyl = lin(ones(Np, 1), 4);
+ dxp = point(:, 1) - lin(1);
+ dyp = point(:, 2) - lin(2);
+
+ else
+ % expand one of the array to have the same size
+ dxl = repmat(lin(:,3)', Np, 1);
+ dyl = repmat(lin(:,4)', Np, 1);
+ dxp = repmat(point(:,1), 1, Nl) - repmat(lin(:,1)', Np, 1);
+ dyp = repmat(point(:,2), 1, Nl) - repmat(lin(:,2)', Np, 1);
+ end
+
+ % compute position
+ d = (dxp.*dxl + dyp.*dyl) ./ (dxl.^2 + dyl.^2);
+
+endfunction
+
+%!demo
+%! point = [20 60;10 30;25 75];
+%! lin = createLine([10 30], [30 90]);
+%! pos = linePosition(point, lin)
+%!
+%! plot(point(:,1),point(:,2),'ok');
+%! hold on
+%! drawLine(lin,'color','r');
+%! plot(lin(1)+lin(3)*pos,lin(2)+lin(4)*pos,'xb')
+%! hold off
+
+%!test
+%! point = [20 60];
+%! lin = createLine([10 30], [30 90]);
+%! res = .5;
+%! pos = linePosition(point, lin);
+%! assert (res, pos);
+
+%!test
+%! point = [20 60;10 30;25 75];
+%! lin = createLine([10 30], [30 90]);
+%! res = [.5; 0; .75];
+%! pos = linePosition(point, lin);
+%! assert (res, pos);
+
+%!test
+%! point = [20 60];
+%! lin1 = createLine([10 30], [30 90]);
+%! lin2 = createLine([0 0], [20 60]);
+%! lin3 = createLine([20 60], [40 120]);
+%! lines = [lin1;lin2;lin3];
+%! res = [.5; 1; 0];
+%! pos = linePosition(point, lines);
+%! assert (res, pos);
+
git://git.creatis.insa-lyon.fr / CreaPhase.git / blobdiff