/usr/share/octave/packages/nurbs-1.3.10/nrbtform.m is in octave-nurbs 1.3.10-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 | function nurbs = nrbtform(nurbs,tmat)
%
% NRBTFORM: Apply transformation matrix to the NURBS.
%
% Calling Sequence:
%
% tnurbs = nrbtform(nurbs,tmatrix);
%
% INPUT:
%
% nurbs : NURBS data structure (see nrbmak for details).
%
% tmatrix : Transformation matrix, a matrix of size (4,4) defining
% a single or multiple transformations.
%
% OUTPUT:
%
% tnurbs : The return transformed NURBS data structure.
%
% Description:
%
% The NURBS is transform as defined a transformation matrix of size (4,4),
% such as a rotation, translation or change in scale. The transformation
% matrix can define a single transformation or multiple series of
% transformations. The matrix can be simply constructed by the functions
% vecscale, vectrans and vecrot, and also vecrotx, vecroty, and vecrotz.
%
% Examples:
%
% Rotate a square by 45 degrees about the z axis.
%
% rsqr = nrbtform(nrbrect(), vecrotz(deg2rad(45)));
% nrbplot(rsqr, 1000);
%
% See also:
%
% vecscale, vectrans, vecrot, vecrotx, vecroty, vecrotz
%
% Copyright (C) 2000 Mark Spink
% Copyright (C) 2010 Rafael Vazquez
%
% 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
% (at your option) 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/>.
if nargin < 2
error('Not enough input arguments!');
end;
if iscell(nurbs.knots)
if size(nurbs.knots,2) == 2
% NURBS is a surface
[dim,nu,nv] = size(nurbs.coefs);
nurbs.coefs = reshape(tmat*reshape(nurbs.coefs,dim,nu*nv),[dim nu nv]);
elseif size(nurbs.knots,2) == 3
% NURBS is a volume
[dim,nu,nv,nw] = size(nurbs.coefs);
nurbs.coefs = reshape(tmat*reshape(nurbs.coefs,dim,nu*nv*nw),[dim nu nv nw]);
end
else
% NURBS is a curve
nurbs.coefs = tmat*nurbs.coefs;
end
end
%!demo
%! xx = vectrans([2.0 1.0])*vecroty(pi/8)*vecrotx(pi/4)*vecscale([1.0 2.0]);
%! c0 = nrbtform(nrbcirc, xx);
%! nrbplot(c0,50);
%! grid on
%! title('Construction of an ellipse by transforming a unit circle.');
%! hold off
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