--- /dev/null
+%% Copyright (c) 2011, INRA
+%% 2003-2011, 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{h} = } drawCircle (@var{x0}, @var{y0}, @var{r})
+%% @deftypefnx {Function File} {@var{h} = } drawCircle (@var{circle})
+%% @deftypefnx {Function File} {@var{h} = } drawCircle (@var{center}, @var{radius})
+%% @deftypefnx {Function File} {@var{h} = } drawCircle (@dots{}, @var{nstep})
+%% @deftypefnx {Function File} {@var{h} = } drawCircle (@dots{}, @var{name}, @var{value})
+%% Draw a circle on the current axis
+%%
+%% drawCircle(X0, Y0, R);
+%% Draw the circle with center (X0,Y0) and the radius R. If X0, Y0 and R
+%% are column vectors of the same length, draw each circle successively.
+%%
+%% drawCircle(CIRCLE);
+%% Concatenate all parameters in a Nx3 array, where N is the number of
+%% circles to draw.
+%%
+%% drawCircle(CENTER, RADIUS);
+%% Specify CENTER as Nx2 array, and radius as a Nx1 array.
+%%
+%% drawCircle(..., NSTEP);
+%% Specify the number of edges that will be used to draw the circle.
+%% Default value is 72, creating an approximation of one point for each 5
+%% degrees.
+%%
+%% drawCircle(..., NAME, VALUE);
+%% Specifies plotting options as pair of parameters name/value. See plot
+%% documentation for details.
+%%
+%%
+%% H = drawCircle(...);
+%% return handles to each created curve.
+%%
+%% @seealso{circles2d, drawCircleArc, drawEllipse}
+%% @end deftypefn
+
+function varargout = drawCircle(varargin)
+
+ % process input parameters
+ var = varargin{1};
+ if size(var, 2) == 1
+ x0 = varargin{1};
+ y0 = varargin{2};
+ r = varargin{3};
+ varargin(1:3) = [];
+
+ elseif size(var, 2) == 2
+ x0 = var(:,1);
+ y0 = var(:,2);
+ r = varargin{2};
+ varargin(1:2) = [];
+
+ elseif size(var, 2) == 3
+ x0 = var(:,1);
+ y0 = var(:,2);
+ r = var(:,3);
+ varargin(1) = [];
+ else
+ error('bad format for input in drawCircle');
+ end
+
+ % ensure each parameter is column vector
+ x0 = x0(:);
+ y0 = y0(:);
+ r = r(:);
+
+ % default number of discretization steps
+ N = 72;
+
+ % check if discretization step is specified
+ if ~isempty(varargin)
+ var = varargin{1};
+ if length(var)==1 && isnumeric(var)
+ N = round(var);
+ varargin(1) = [];
+ end
+ end
+
+ % parametrization variable for circle (use N+1 as first point counts twice)
+ t = linspace(0, 2*pi, N+1);
+ cot = cos(t);
+ sit = sin(t);
+
+ % empty array for graphic handles
+ h = zeros(size(x0));
+
+ % compute discretization of each circle
+ for i = 1:length(x0)
+ xt = x0(i) + r(i) * cot;
+ yt = y0(i) + r(i) * sit;
+
+ h(i) = plot(xt, yt, varargin{:});
+ end
+
+ if nargout > 0
+ varargout = {h};
+ end
+
+endfunction
+