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
|
## Copyright (C) 2024 David Legland
## All rights reserved.
##
## 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 AUTHOR 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 the copyright holders.
function T = createHomothecy(point, ratio)
%CREATEHOMOTHECY Create the the 3x3 matrix of an homothetic transform.
%
% TRANS = createHomothecy(POINT, K);
% POINT is the center of the homothecy, K is its factor.
% TRANS is a 3-by-3 matrix representing the homothetic transform in
% homogeneous coordinates.
%
% Example:
%
% p = [0 0; 1 0; 0 1];
% s = [-0.5 0.4];
% T = createHomothecy (s, 1.5);
% pT = transformPoint (p, T);
% drawPolygon (p,'-b')
% hold on;
% drawPolygon (pT, '-r');
%
% drawEdge (p(:,1), p(:,2), pT(:,1), pT(:,2), ...
% 'color', 'k','linestyle','--')
% hold off
% axis tight equal
%
% ------
% Author: David Legland
% E-mail: david.legland@inrae.fr
% Created: 2005-01-20
% Copyright 2005-2023 INRA - TPV URPOI - BIA IMASTE
point = point(:);
if length (point) > 2
error('Only one point accepted.');
end
if length (ratio) > 1
error('Only one ratio accepted.');
end
T = diag ([ratio ratio 1]);
T(1:2,3) = point .* (1 - ratio);
|
