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## Copyright (C) 2024 David Legland
## All rights reserved.
##
## 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 AUTHOR 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 the copyright holders.
function varargout = projPointOnPolygon(point, poly, varargin)
%PROJPOINTONPOLYGON Compute position of a point projected on a polygon.
%
% POS = projPointOnPolygon(POINT, POLYGON)
% Compute the position of the orthogonal projection of a point on a
% polygon.
% POINT is a 1-by-2 row vector containing point coordinates
% POLYGON is a N-by-2 array containing coordinates of polygon vertices
%
% When POINT is an array of points, returns a column vector with as many
% rows as the number of points.
%
% [POS, DIST] = projPointOnPolygon(...)
% Also returns the distance between POINT and POLYGON. The distance is
% negative if the point is located inside of the polygon.
%
% Example
% poly = [10 10; 20 10;20 20;10 20];
% projPointOnPolygon([15 0], poly)
% ans =
% 0.5000
% projPointOnPolygon([0 16], poly)
% ans =
% 3.4000
%
% See also
% points2d, polygons2d, polygonPoint, projPointOnPolyline
% distancePointpolygon
%
% ------
% Author: David Legland
% E-mail: david.legland@inrae.fr
% Created: 2009-04-30, using Matlab 7.7.0.471 (R2008b)
% Copyright 2009-2023 INRA - Cepia Software Platform
% eventually copy first point at the end to ensure closed polygon
if sum(poly(end, :) == poly(1,:)) ~= 2
poly = [poly; poly(1,:)];
end
% compute position wrt outline
[pos, minDist] = projPointOnPolyline(point, poly);
% process output arguments
if nargout <= 1
varargout{1} = pos;
elseif nargout == 2
varargout{1} = pos;
if inpolygon(point(:,1), point(:,2), poly(:,1), poly(:,2))
minDist = -minDist;
end
varargout{2} = minDist;
end
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