Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / geometry-1.5.0 / polygons2d / splitPolygons.m

diff --git a/octave_packages/geometry-1.5.0/polygons2d/splitPolygons.m b/octave_packages/geometry-1.5.0/polygons2d/splitPolygons.m
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+++ b/octave_packages/geometry-1.5.0/polygons2d/splitPolygons.m
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+## Copyright (C) 2003-2011 David Legland <david.legland@grignon.inra.fr>
+## Copyright (C) 2012 Adapted to Octave by Juan Pablo Carbajal <carbajal@ifi.uzh.ch>
+## 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.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{polygons} = } splitPolygons (@var{polygon})
+## Convert a NaN separated polygon list to a cell array of polygons.
+##
+## @var{polygon} is a N-by-2 array of points, with possibly couples of NaN values.
+## The functions separates each component separated by NaN values, and
+## returns a cell array of polygons.
+##
+## @seealso{polygons2d}
+## @end deftypefn
+function polygons = splitPolygons(polygon)
+
+  if iscell(polygon)
+      # case of a cell array
+      polygons = polygon;
+      
+  elseif sum(isnan(polygon(:)))==0
+      # single polygon -> no break
+      polygons = {polygon};
+      
+  else
+      # find indices of NaN couples
+      inds = find(sum(isnan(polygon), 2)>0);
+      
+      # number of polygons
+      N = length(inds)+1;
+      polygons = cell(N, 1);
+
+      # iterate over NaN-separated regions to create new polygon
+      inds = [0;inds;size(polygon, 1)+1];
+      for i=1:N
+          polygons{i} = polygon((inds(i)+1):(inds(i+1)-1), :);    
+      end
+  end
+
+endfunction