/usr/share/doc/libplplot11/examples/octave/x27c.m is in octave-plplot 5.9.9-2ubuntu2.
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 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 | ## $Id: x27c.m 11857 2011-08-04 23:34:19Z andrewross $
##
## Drawing "spirograph" curves - epitrochoids, cycolids, roulettes
##
## Copyright (C) 2007 Arjen Markus
## Copyright (C) 2008 Andrew Ross
##
## This file is part of PLplot.
##
## PLplot is free software; you can redistribute it and/or modify
## it under the terms of the GNU Library General Public License as published
## by the Free Software Foundation; either version 2 of the License, or
## (at your option) any later version.
##
## PLplot 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 Library General Public License for more details.
##
## You should have received a copy of the GNU Library General Public License
## along with PLplot; if not, write to the Free Software
## Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
##
1;
function ix27c
##--------------------------------------------------------------------------*\
## Generates two kinds of plots:
## - construction of a cycloid (animated)
## - series of epitrochoids and hypotrochoids
##--------------------------------------------------------------------------*/
## R, r, p, N
## R and r should be integers to give correct termination of the
## angle loop using gcd.
## N.B. N is just a place holder since it is no longer used
## (because we now have proper termination of the angle loop).
params = [
21.0, 7.0, 7.0, 3.0; ## Deltoid
21.0, 7.0, 10.0, 3.0;
21.0, -7.0, 10.0, 3.0;
20.0, 3.0, 7.0, 20.0;
20.0, 3.0, 10.0, 20.0;
20.0, -3.0, 10.0, 20.0;
20.0, 13.0, 7.0, 20.0;
20.0, 13.0, 20.0, 20.0;
20.0,-13.0, 20.0, 20.0];
## Parse and process command line arguments
## (void) plparseopts(&argc, argv, PL_PARSE_FULL);
## Initialize plplot
plinit();
## Illustrate the construction of a cycloid
cycloid();
## Loop over the various curves
## First an overview, then all curves one by one
plssub(3, 3); ## Three by three window
fill = 0;
for i = 1:9
pladv(0);
plvpor( 0.0, 1.0, 0.0, 1.0 );
spiro( params(i,:), fill );
endfor
pladv(0);
plssub(1, 1); ## One window per curve
for i=1:9
pladv(0);
plvpor( 0.0, 1.0, 0.0, 1.0 );
spiro( params(i,:), fill );
endfor
## Fill the curves.
fill = 1;
pladv( 0 );
plssub( 1, 1 ); ## One window per curve
for i=1:9
pladv(0);
plvpor( 0.0, 1.0, 0.0, 1.0 );
spiro( params(i,:), fill );
endfor
## Finally, an example to test out plarc capabilities
arcs();
## Don't forget to call plend() to finish off!
plend1();
end
##------------------------------------------------------------------------
## Calculate greatest common divisor following pseudo-code for the
## Euclidian algorithm at http://en.wikipedia.org/wiki/Euclidean_algorithm
function [value] = gcd (a, b)
a = floor(abs(a));
b = floor(abs(b));
while(b!=0)
t = b;
b = mod(a,b);
a = t;
endwhile
value = a;
end
## ===============================================================
function cycloid()
## TODO
endfunction
## ===============================================================
function spiro(params, fill)
NPNT=2000;
## Fill the coordinates
## Proper termination of the angle loop very near the beginning
## point, see
## http://mathforum.org/mathimages/index.php/Hypotrochoid.
windings = floor(abs(params(2))/gcd(params(1), params(2)));
steps = floor(NPNT/windings);
dphi = 2.0*pi/steps;
i = (0:windings*steps)';
phi = i*dphi;
phiw = (params(1)-params(2))/params(2)*phi;
xcoord = (params(1)-params(2))*cos(phi) + params(3)*cos(phiw);
ycoord = (params(1)-params(2))*sin(phi) - params(3)*sin(phiw);
xmin = min(xcoord);
xmax = max(xcoord);
ymin = min(ycoord);
ymax = max(ycoord);
xrange_adjust = 0.15 * (xmax - xmin);
xmin -= xrange_adjust;
xmax += xrange_adjust;
yrange_adjust = 0.15 * (ymax - ymin);
ymin -= yrange_adjust;
ymax += yrange_adjust;
plwind( xmin, xmax, ymin, ymax );
plcol0(1);
if ( fill )
plfill( xcoord, ycoord );
else
plline( xcoord, ycoord );
endif
endfunction
function arcs
NSEG = 8;
theta = 0.0;
dtheta = 360.0 / NSEG;
plenv( -10.0, 10.0, -10.0, 10.0, 1, 0 );
## Plot segments of circle in different colors
for i = 0:NSEG-1
plcol0( mod(i,2) + 1 );
plarc(0.0, 0.0, 8.0, 8.0, theta, theta + dtheta, 0.0, 0);
theta = theta + dtheta;
endfor
## Draw several filled ellipses inside the circle at different
## angles.
a = 3.0;
b = a * tan( (dtheta/180.0*pi)/2.0 );
theta = dtheta/2.0;
for i = 0:NSEG-1
plcol0( 2 - mod(i,2) );
plarc( a*cos(theta/180.0*pi), a*sin(theta/180.0*pi), a, b, 0.0, 360.0, theta, 1);
theta = theta + dtheta;
endfor
endfunction
ix27c
|