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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 len = polylineLength(poly, varargin)
%POLYLINELENGTH Return length of a polyline given as a list of points.
%
% L = polylineLength(POLY);
% POLY should be a N-by-D array, where N is the number of points and D is
% the dimension of the points.
%
% L = polylineLength(..., TYPE);
% Specifies if the last point is connected to the first one. TYPE can be
% either 'closed' or 'open'.
%
% L = polylineLength(POLY, POS);
% Compute the length of the polyline between its origin and the position
% given by POS. POS should be between 0 and N-1, where N is the number of
% points of the polyline.
%
%
% Example:
% % Compute the perimeter of a circle with radius 1
% polylineLength(circleAsPolygon([0 0 1], 500), 'closed')
% ans =
% 6.2831
%
% See also
% polygons2d, polylineCentroid, polygonLength
% ------
% 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
% check there are enough points
if size(poly, 1) < 2
len = 0;
return;
end
% check whether the curve is closed or not (default is open)
closed = false;
if ~isempty(varargin)
var = varargin{end};
if ischar(var)
if strcmpi(var, 'closed')
closed = true;
end
varargin = varargin(1:end-1);
end
end
% if the length is computed between 2 positions, compute only for a
% subcurve
if ~isempty(varargin)
% values for 1 input argument
t0 = 0;
t1 = varargin{1};
% values for 2 input arguments
if length(varargin)>1
t0 = varargin{1};
t1 = varargin{2};
end
% extract a portion of the polyline
poly = polylineSubcurve(poly, t0, t1);
end
% compute lengths of each line segment, and sum up
if closed
len = sum(sqrt(sum(diff(poly([1:end 1],:)).^2, 2)));
else
len = sum(sqrt(sum(diff(poly).^2, 2)));
end
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