Add a useful package (from Source forge) for octave

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

diff --git a/octave_packages/geometry-1.5.0/geom2d/createScaling.m b/octave_packages/geometry-1.5.0/geom2d/createScaling.m
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+++ b/octave_packages/geometry-1.5.0/geom2d/createScaling.m
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+%% Copyright (c) 2011, INRA
+%% 2004-2011, 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} = } createScaling (@var{s})
+%% @deftypefnx {Function File} {@var{T} = } createScaling (@var{sx}, @var{sy})
+%% Create the 3x3 matrix of a scaling in 2 dimensions.
+%
+%   Assume scaling @var{s} is equal n all directions unless @var{sx} and @var{sy} are given.
+%   Returns the matrix corresponding to scaling in the 2 main directions.
+%   The returned matrix has the form:
+%   [SX  0  0]
+%   [0  SY  0]
+%   [0   0  1]
+%
+%   @seealso{transforms2d, transformPoint, createTranslation, createRotation}
+%% @end deftypefn
+
+function trans = createScaling(varargin)
+
+  % defined default arguments
+  sx = 1;
+  sy = 1;
+  cx = 0;
+  cy = 0;
+
+  % process input arguments
+  if length(varargin)==1
+      % the argument is either the scaling factor in both direction,
+      % or a 1x2 array containing scaling factor in each direction
+      var = varargin{1};
+      sx = var(1);
+      sy = var(1);
+      if length(var)>1
+          sy = var(2);
+      end
+  elseif length(varargin)==2
+      % the 2 arguments are the scaling factors in each dimension
+      sx = varargin{1};
+      sy = varargin{2};
+  elseif length(varargin)==3
+      % first argument is center, 2nd and 3d are scaling factors
+      center = varargin{1};
+      cx = center(1);
+      cy = center(2);
+      sx = varargin{2};
+      sy = varargin{3};
+  end
+
+  % create result matrix
+  trans = [sx 0 cx*(1-sx); 0 sy cy*(1-sy); 0 0 1];
+
+endfunction
+
+%!test
+%!  trans = createScaling(2);
+%!  assert (trans, [2 0 0;0 2 0;0 0 1], 1e-6);
+
+%!test
+%!  trans = createScaling(2, 3);
+%!  assert (trans, [2 0 0;0 3 0;0 0 1], 1e-6);
+
+%!test
+%!  trans = createScaling([2 3]);
+%!  assert (trans, [2 0 0;0 3 0;0 0 1], 1e-6);
+
+%!test
+%!  sx = 2;
+%!  sy = 3;
+%!  p0 = [4 5];
+%!  trans1 = createScaling(p0, sx, sy);
+%!  t1 = createTranslation(-p0);
+%!  sca = createScaling(sx, sy);
+%!  t2 = createTranslation(p0);
+%!  trans2 = t2*sca*t1;
+%!  assert (trans1, trans2, 1e-6);