1 %% Copyright (c) 2011, INRA
2 %% 2007-2011, David Legland <david.legland@grignon.inra.fr>
3 %% 2011 Adapted to Octave by Juan Pablo Carbajal <carbajal@ifi.uzh.ch>
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35 %% @deftypefn {Function File} {@var{v2} = } transformVector (@var{v}, @var{T})
36 %% @deftypefnx {Function File} {[@var{x2} @var{y2}] = } transformVector (@var{x},@var{y}, @var{T})
37 %% Transform a vector with an affine transform
39 %% @var{v} has the form [xv yv], and @var{T} is a [2x2], [2x3] or [3x3]
40 %% matrix, returns the vector transformed with affine transform @var{T}.
42 %% Format of @var{T} can be one of :
44 %% [a b] , [a b c] , or [a b c]
45 %% [d e] [d e f] [d e f]
49 %% Also works when @var{v} is a [Nx2] array of double. In this case, @var{v2} has
50 %% the same size as @var{v}.
52 %% Also works when @var{x} and @var{y} are arrays the same size. The function
53 %% transform each couple of (@var{x}, @var{y}), and return the result in
54 %% (@var{x2}, @var{y2}), which is the same size as (@var{x}, @var{y}).
56 %% @seealso{vectors2d, transforms2d, rotateVector, transformPoint}
59 function varargout = transformVector(varargin)
61 if length(varargin)==2
66 elseif length(varargin)==3
71 error('wrong number of arguments in "transformVector"');
75 % compute new position of vector
76 vx2 = vx*trans(1,1) + vy*trans(1,2);
77 vy2 = vx*trans(2,1) + vy*trans(2,2);
79 if size(trans, 2) == 3
80 vx2 = vx2 + trans(1,3);
81 vy2 = vy2 + trans(2,3);
85 if nargout==0 || nargout==1
86 varargout{1} = [vx2 vy2];
95 %! t1 = [2 0 0; 0 2 0];
96 %! t2 = [1 0 1; 0 1 1];
97 %! t3 = [0.5 0 1; 0 0.5 1; 0 0 1];
99 %! triangle = [-0.5 -1/3; 0.5 -1/3; 0 2/3; -0.5 -1/3];
100 %! tr1 = transformVector(triangle,t1);
101 %! tr2 = transformVector(triangle,t2);
102 %! tr3 = transformVector(triangle,t3);
104 %! plot(triangle(:,1),triangle(:,2),'k-', ...
105 %! tr1(:,1),tr1(:,2),'g-;scaled up;', ...
106 %! tr2(:,1),tr2(:,2),'m-;translated;', ...
107 %! tr3(:,1),tr3(:,2),'b-;scaled down and translated;')