--- /dev/null
+%% Copyright (c) 2011, INRA
+%% 2007-2011, 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{v2} = } transformVector (@var{v}, @var{T})
+%% @deftypefnx {Function File} {[@var{x2} @var{y2}] = } transformVector (@var{x},@var{y}, @var{T})
+%% Transform a vector with an affine transform
+%%
+%% @var{v} has the form [xv yv], and @var{T} is a [2x2], [2x3] or [3x3]
+%% matrix, returns the vector transformed with affine transform @var{T}.
+%%
+%% Format of @var{T} can be one of :
+%% @group
+%% [a b] , [a b c] , or [a b c]
+%% [d e] [d e f] [d e f]
+%% [0 0 1]
+%% @end group
+%%
+%% Also works when @var{v} is a [Nx2] array of double. In this case, @var{v2} has
+%% the same size as @var{v}.
+%%
+%% Also works when @var{x} and @var{y} are arrays the same size. The function
+%% transform each couple of (@var{x}, @var{y}), and return the result in
+%% (@var{x2}, @var{y2}), which is the same size as (@var{x}, @var{y}).
+%%
+%% @seealso{vectors2d, transforms2d, rotateVector, transformPoint}
+%% @end deftypefn
+
+function varargout = transformVector(varargin)
+
+ if length(varargin)==2
+ var = varargin{1};
+ vx = var(:,1);
+ vy = var(:,2);
+ trans = varargin{2};
+ elseif length(varargin)==3
+ vx = varargin{1};
+ vy = varargin{2};
+ trans = varargin{3};
+ else
+ error('wrong number of arguments in "transformVector"');
+ end
+
+
+ % compute new position of vector
+ vx2 = vx*trans(1,1) + vy*trans(1,2);
+ vy2 = vx*trans(2,1) + vy*trans(2,2);
+
+ if size(trans, 2) == 3
+ vx2 = vx2 + trans(1,3);
+ vy2 = vy2 + trans(2,3);
+ end
+
+ % format output
+ if nargout==0 || nargout==1
+ varargout{1} = [vx2 vy2];
+ elseif nargout==2
+ varargout{1} = vx2;
+ varargout{2} = vy2;
+ end
+
+endfunction
+
+%!demo
+%! t1 = [2 0 0; 0 2 0];
+%! t2 = [1 0 1; 0 1 1];
+%! t3 = [0.5 0 1; 0 0.5 1; 0 0 1];
+%!
+%! triangle = [-0.5 -1/3; 0.5 -1/3; 0 2/3; -0.5 -1/3];
+%! tr1 = transformVector(triangle,t1);
+%! tr2 = transformVector(triangle,t2);
+%! tr3 = transformVector(triangle,t3);
+%!
+%! plot(triangle(:,1),triangle(:,2),'k-', ...
+%! tr1(:,1),tr1(:,2),'g-;scaled up;', ...
+%! tr2(:,1),tr2(:,2),'m-;translated;', ...
+%! tr3(:,1),tr3(:,2),'b-;scaled down and translated;')
+