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%% Copyright (c) 2011, INRA
%% 2009-2011, 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{T} = } createHomothecy (@var{point}, @var{ratio})
%% Create the the 3x3 matrix of an homothetic transform.
%
% @var{point} is the center of the homothecy, @var{ratio} is its factor.
%
% @seealso{transforms2d, transformPoint, createTranslation}
%% @end deftypefn
function trans = createHomothecy(point, ratio)
% extract coordinate of center
x0 = point(:,1);
y0 = point(:,2);
% compute coefficients of the matrix
m00 = ratio;
m01 = 0;
m02 = x0*(1-ratio);
m10 = 0;
m11 = ratio;
m12 = y0*(1-ratio);
% create transformation
trans = [m00 m01 m02; m10 m11 m12; 0 0 1];
endfunction
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