1 %% Copyright (c) 2011, INRA
2 %% 2004-2011, 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{T} = } createScaling (@var{s})
36 %% @deftypefnx {Function File} {@var{T} = } createScaling (@var{sx}, @var{sy})
37 %% Create the 3x3 matrix of a scaling in 2 dimensions.
39 % Assume scaling @var{s} is equal n all directions unless @var{sx} and @var{sy} are given.
40 % Returns the matrix corresponding to scaling in the 2 main directions.
41 % The returned matrix has the form:
46 % @seealso{transforms2d, transformPoint, createTranslation, createRotation}
49 function trans = createScaling(varargin)
51 % defined default arguments
57 % process input arguments
58 if length(varargin)==1
59 % the argument is either the scaling factor in both direction,
60 % or a 1x2 array containing scaling factor in each direction
67 elseif length(varargin)==2
68 % the 2 arguments are the scaling factors in each dimension
71 elseif length(varargin)==3
72 % first argument is center, 2nd and 3d are scaling factors
80 % create result matrix
81 trans = [sx 0 cx*(1-sx); 0 sy cy*(1-sy); 0 0 1];
86 %! trans = createScaling(2);
87 %! assert (trans, [2 0 0;0 2 0;0 0 1], 1e-6);
90 %! trans = createScaling(2, 3);
91 %! assert (trans, [2 0 0;0 3 0;0 0 1], 1e-6);
94 %! trans = createScaling([2 3]);
95 %! assert (trans, [2 0 0;0 3 0;0 0 1], 1e-6);
101 %! trans1 = createScaling(p0, sx, sy);
102 %! t1 = createTranslation(-p0);
103 %! sca = createScaling(sx, sy);
104 %! t2 = createTranslation(p0);
105 %! trans2 = t2*sca*t1;
106 %! assert (trans1, trans2, 1e-6);