Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / geometry-1.5.0 / geom2d / createDirectedCircle.m

diff --git a/octave_packages/geometry-1.5.0/geom2d/createDirectedCircle.m b/octave_packages/geometry-1.5.0/geom2d/createDirectedCircle.m
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+%% Copyright (c) 2011, INRA
+%% 2005-2011, 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 PURPOSE
+%% 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
+%% 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 copyright holder.
+
+%% -*- texinfo -*-
+%% @deftypefn {Function File} {@var{circle} = } createDirectedCircle (@var{p1}, @var{p2}, @var{p3})
+%% @deftypefnx {Function File} {@var{circle} = } createDirectedCircle (@var{p1}, @var{p2})
+%% Create a circle from 2 or 3 points.
+%%
+%%   Creates the circle passing through the 3 given points. 
+%%   C is a 1x4 array of the form: [XC YX R INV].
+%%
+%% When two points are given, creates the circle whith center @var{p1} and passing
+%% throuh the point @var{p2}.
+%%
+%%   Works also when input are point arrays the same size, in this case the
+%%   result has as many lines as the point arrays.
+%%
+%%   Example
+%% 
+%%
+%%   @seealso{circles2d, createCircle}
+%% @end deftypefn
+
+function circle = createDirectedCircle(varargin)
+
+  if nargin == 2
+      % inputs are the center and a point on the circle
+      p1 = varargin{1};
+      p2 = varargin{2};
+      x0 = (p1(:,1) + p2(:,1))/2;
+      y0 = (p1(:,2) + p2(:,2))/2;
+      r = hypot((p2(:,1)-p1(:,1)), (p2(:,2)-p1(:,2)))/2;
+      
+      % circle is direct by default
+      d = 0;
+      
+  elseif nargin == 3
+      % inputs are three points on the circle
+      p1 = varargin{1};
+      p2 = varargin{2};
+      p3 = varargin{3};
+
+      % compute circle center
+      line1 = medianLine(p1, p2);
+      line2 = medianLine(p1, p3);
+      center = intersectLines(line1, line2);
+      x0 = center(:, 1); 
+      y0 = center(:, 2);
+      
+      % circle radius
+      r = hypot((p1(:,1)-x0), (p1(:,2)-y0));
+      
+      % compute circle orientation
+      angle = angle3Points(p1, center, p2) + angle3Points(p2, center, p3);
+      d = angle>2*pi;
+  end
+      
+          
+  circle = [x0 y0 r d];
+
+endfunction
+