From b78bdf8180be1f4c86452ab46a7fc663e3472d0a Mon Sep 17 00:00:00 2001
From: Rafael Laboissiere <rafael@laboissiere.net>
Date: Sun, 18 Mar 2012 18:37:21 +0100
Subject: Imported Upstream version 1.4.0

---
 inst/polygons2d/simplifypolygon.m | 60 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)
 create mode 100644 inst/polygons2d/simplifypolygon.m

(limited to 'inst/polygons2d/simplifypolygon.m')

diff --git a/inst/polygons2d/simplifypolygon.m b/inst/polygons2d/simplifypolygon.m
new file mode 100644
index 0000000..31db2d5
--- /dev/null
+++ b/inst/polygons2d/simplifypolygon.m
@@ -0,0 +1,60 @@
+## Copyright (c) 2011 Juan Pablo Carbajal <carbajal@ifi.uzh.ch>
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, see <http://www.gnu.org/licenses/>.
+
+%% -*- texinfo -*-
+%% @deftypefn {Function File} {@var{spoly} = } simplifypolygon (@var{poly})
+%% Filter colinear vertex from a 2D polygon.
+%%
+%% @var{poly} is a N-by-2 matrix, each row representing a vertex.
+%%
+%% @seealso{shape2polygon}
+%% @end deftypefn
+
+function polygonsimp = simplifypolygon (polygon)
+
+  # Filter colinear points
+  edges = diff(polygon([1:end 1],:));
+  ned = size(edges,1);
+  nxt = [2:ned 1];
+
+  # check if consecutive edges are parallel
+  para = edges(:,1).*edges(nxt,2) - edges(:,2).*edges(nxt,1);
+  ind = abs(para) > sqrt(eps);
+
+  polygonsimp = polygon(circshift (ind,1),:);
+
+endfunction
+
+%!test
+%!  P = [0 0; 1 0; 0 1];
+%!  P2 = [0 0; 0.1 0; 0.2 0; 0.25 0; 1 0; 0 1; 0 0.7; 0 0.6; 0 0.3; 0 0.1];
+%! assert(P,simplifypolygon (P2))
+
+%!demo
+%!
+%!  P = [0 0; 1 0; 0 1];
+%!  P2 = [0 0; 0.1 0; 0.2 0; 0.25 0; 1 0; 0 1; 0 0.7; 0 0.6; 0 0.3; 0 0.1];
+%!  Pr = simplifypolygon (P2);
+%!
+%!  cla
+%!  drawPolygon(P,'or;Reference;');
+%!  hold on
+%!  drawPolygon(P2,'x-b;Redundant;');
+%!  drawPolygon(Pr,'*g;Simplified;');
+%!  hold off
+%!
+%! % --------------------------------------------------------------------------
+%! % The two polygons describe the same figure, a triangle. Extra points are
+%! % removed form the redundant one.
-- 
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