/usr/share/octave/packages/geometry-1.7.0/geom2d/ellipseAsPolygon.m is in octave-geometry 1.7.0-1build1.
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 83 84 | ## Copyright (C) 2004-2011 David Legland <david.legland@grignon.inra.fr>
## Copyright (C) 2004-2011 INRA - CEPIA Nantes - MIAJ (Jouy-en-Josas)
## Copyright (C) 2012 Adapted to Octave by Juan Pablo Carbajal <carbajal@ifi.uzh.ch>
## 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.
## -*- texinfo -*-
## @deftypefn {Function File} {@var{p} = } ellipseAsPolygon (@var{ell}, @var{n})
## Convert an ellipse into a series of points
##
## P = ellipseAsPolygon(ELL, N);
## converts ELL given as [x0 y0 a b] or [x0 y0 a b theta] into a polygon
## with N edges. The result P is (N+1)-by-2 array containing coordinates
## of the N+1 vertices of the polygon.
## The resulting polygon is closed, i.e. the last point is the same as the
## first one.
##
## P = ellipseAsPolygon(ELL);
## Use a default number of edges equal to 72. This result in one piont for
## each 5 degrees.
##
## [X Y] = ellipseAsPolygon(...);
## Return the coordinates o fvertices in two separate arrays.
##
## @seealso{ellipses2d, circleAsPolygon, rectAsPolygon, drawEllipse}
## @end deftypefn
function varargout = ellipseAsPolygon(ellipse, N)
# default value for N
if nargin < 2
N = 72;
end
# angle of ellipse
theta = 0;
if size(ellipse, 2) > 4
theta = ellipse(:,5);
end
# get ellipse parameters
xc = ellipse(:,1);
yc = ellipse(:,2);
a = ellipse(:,3);
b = ellipse(:,4);
# create time basis
t = linspace(0, 2*pi, N+1)';
# pre-compute trig functions (angles is in degrees)
cot = cosd(theta);
sit = sind(theta);
# position of points
x = xc + a * cos(t) * cot - b * sin(t) * sit;
y = yc + a * cos(t) * sit + b * sin(t) * cot;
# format output depending on number of a param.
if nargout == 1
varargout = {[x y]};
elseif nargout == 2
varargout = {x, y};
end
endfunction
|