Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / geometry-1.5.0 / shape2d / shapetransform.m

diff --git a/octave_packages/geometry-1.5.0/shape2d/shapetransform.m b/octave_packages/geometry-1.5.0/shape2d/shapetransform.m
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+++ b/octave_packages/geometry-1.5.0/shape2d/shapetransform.m
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+%% Copyright (c) 2011 Juan Pablo Carbajal <carbajal@ifi.uzh.ch>
+%%
+%%    This program is free software: you can redistribute it and/or modify
+%%    it under the terms of the GNU General Public License as published by
+%%    the Free Software Foundation, either version 3 of the License, or
+%%    any later version.
+%%
+%%    This program is distributed in the hope that it will be useful,
+%%    but WITHOUT ANY WARRANTY; without even the implied warranty of
+%%    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+%%    GNU General Public License for more details.
+%%
+%%    You should have received a copy of the GNU General Public License
+%%    along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+%% -*- texinfo -*-
+%% @deftypefn {Function File} {@var{nshape} = } shapetransform (@var{shape}, @var{T})
+%% Applies transformation to a shape defined by piecewise smooth polynomials.
+%%
+%% @var{shape} is a cell where each elements is a 2-by-(poly_degree+1) matrix
+%% containing a pair of polynomials.
+%%
+%% Format of @var{T} can be one of :
+%% @example
+%% @group
+%%  [c] , [a b] , [a b c] or [a b c]
+%%  [f]   [d e]   [d e f]    [d e f]
+%%                           [0 0 1]
+%% @end group
+%% @end example
+%%
+%% @seealso{shape2polygon, shapeplot}
+%% @end deftypefn
+
+function nshape = shapetransform (shape, Trans)
+
+  if size(Trans,1) < 2
+    error("geometry:shapetransform:InvalidArgument", ...
+                       "Transformation can be 2x1, 2x2, 2x3 or 3x3. See help.");
+  end
+
+  if ~iscell(shape)
+    error("geometry:shapetransform:InvalidArgument", "Shape must be a cell of 2D polynomials.");
+  end
+
+  A =[];
+  v = [];
+
+  switch size(Trans,2)
+    case 1
+    % Just translation
+      v = Trans;
+
+    case 2
+    % Just linear transformation
+      A = Trans;
+
+    case 3
+    % Affine transform
+      A = Trans(1:2,1:2);
+      v = Trans(1:2,3);
+  end
+
+  nshape = cellfun (@(x)polytransform (x,A,v), shape, 'UniformOutput',false);
+
+endfunction
+
+function np = polytransform(p,A,v)
+
+  np = p;
+  if ~isempty (A)
+    np = A*np;
+  end
+  if ~isempty (v)
+    np(:,end) = np(:,end) + v;
+  end
+
+endfunction
+
+%!demo
+%! shape = {[-93.172   606.368  -476.054   291.429; ...
+%!          -431.196   637.253    11.085   163.791]; ...
+%!         [-75.3626  -253.2337   457.1678   328.5714; ...
+%!           438.7659  -653.6278    -7.9953   380.9336]; ...
+%!         [-89.5841   344.9716  -275.3876   457.1429; ...
+%!          -170.3613   237.8858     1.0469   158.0765];...
+%!         [32.900  -298.704   145.804   437.143; ...
+%!         -243.903   369.597   -34.265   226.648]; ...
+%!         [-99.081   409.127  -352.903   317.143; ...
+%!           55.289  -114.223   -26.781   318.076]; ...
+%!         [-342.231   191.266   168.108   274.286; ...
+%!           58.870   -38.083   -89.358   232.362]};
+%!
+%! A = shapearea (shape);
+%! T = eye(2)/sqrt(A);
+%! shape = shapetransform (shape,T);
+%! T = shapecentroid (shape)(:);
+%! shape = shapetransform (shape,-T + [2; 0]);
+%!
+%! close
+%! shapeplot (shape,'-r','linewidth',2);
+%! hold on
+%! for i = 1:9
+%!   T = createRotation (i*pi/5)(1:2,1:2)/exp(0.3*i);
+%!   shapeplot (shapetransform(shape, T), 'color',rand(1,3),'linewidth',2);
+%! end
+%! hold off
+%! axis tight
+%! axis square