/usr/share/doc/libplplot12/examples/d/x27d.d is in libplplot-dev 5.10.0+dfsg-1.
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//
// Drawing "spirograph" curves - epitrochoids, cycolids, roulettes
//
// Copyright (C) 2009 Werner Smekal
//
// 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
//
//
import std.string;
import std.math;
import plplot;
//--------------------------------------------------------------------------
// main
//
// Generates two kinds of plots:
// - construction of a cycloid (animated)
// - series of epitrochoids and hypotrochoids
//--------------------------------------------------------------------------
int main( char[][] args )
{
// 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).
static PLFLT[4][9] 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 ]
];
// plplot initialization
// Parse and process command line arguments
plparseopts( args, 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
int fill = 0;
for ( int i = 0; i < 9; i++ )
{
pladv( 0 );
plvpor( 0.0, 1.0, 0.0, 1.0 );
spiro( params[i], fill );
}
pladv( 0 );
plssub( 1, 1 ); // One window per curve
for ( int i = 0; i < 9; i++ )
{
pladv( 0 );
plvpor( 0.0, 1.0, 0.0, 1.0 );
spiro( params[i], fill );
}
// fill the curves
fill = 1;
pladv( 0 );
plssub( 1, 1 ); // One window per curve
for ( int i = 0; i < 9; i++ )
{
pladv( 0 );
plvpor( 0.0, 1.0, 0.0, 1.0 );
spiro( params[i], fill );
}
// Finally, an example to test out plarc capabilities
arcs();
plend();
return 0;
}
//--------------------------------------------------------------------------
// Calculate greatest common divisor following pseudo-code for the
// Euclidian algorithm at http://en.wikipedia.org/wiki/Euclidean_algorithm
PLINT gcd( PLINT a, PLINT b )
{
PLINT t;
a = abs( a );
b = abs( b );
while ( b != 0 )
{
t = b;
b = a % b;
a = t;
}
return a;
}
//--------------------------------------------------------------------------
void cycloid()
{
// TODO
}
//--------------------------------------------------------------------------
void spiro( PLFLT[] params, int fill )
{
const int npnt = 2000;
PLFLT[] xcoord, ycoord;
int windings, steps;
PLFLT dphi, phi, phiw;
PLFLT xmin, xmax, xrange_adjust;
PLFLT ymin, ymax, yrange_adjust;
// Fill the coordinates
// Proper termination of the angle loop very near the beginning
// point, see
// http://mathforum.org/mathimages/index.php/Hypotrochoid.
windings = cast(PLINT) abs( params[1] ) / gcd( cast(PLINT) params[0], cast(PLINT) params[1] );
steps = npnt / windings;
dphi = 2.0 * PI / cast(PLFLT) steps;
xcoord.length = windings * steps + 1;
ycoord.length = windings * steps + 1;
for ( int i = 0; i <= windings * steps; i++ )
{
phi = i * dphi;
phiw = ( params[0] - params[1] ) / params[1] * phi;
xcoord[i] = ( params[0] - params[1] ) * cos( phi ) + params[2] * cos( phiw );
ycoord[i] = ( params[0] - params[1] ) * sin( phi ) - params[2] * sin( phiw );
if ( i == 0 )
{
xmin = xcoord[i];
xmax = xcoord[i];
ymin = ycoord[i];
ymax = ycoord[i];
}
if ( xmin > xcoord[i] )
xmin = xcoord[i];
if ( xmax < xcoord[i] )
xmax = xcoord[i];
if ( ymin > ycoord[i] )
ymin = ycoord[i];
if ( ymax < ycoord[i] )
ymax = ycoord[i];
}
xrange_adjust = 0.15 * ( xmax - xmin );
xmin = xmin - xrange_adjust;
xmax = xmax + xrange_adjust;
yrange_adjust = 0.15 * ( ymax - ymin );
ymin = ymin - yrange_adjust;
ymax = ymax + yrange_adjust;
plwind( xmin, xmax, ymin, ymax );
plcol0( 1 );
if ( fill )
{
plfill( xcoord, ycoord );
}
else
{
plline( xcoord, ycoord );
}
}
void arcs()
{
const int NSEG = 8;
int i;
PLFLT theta, dtheta;
PLFLT a, b;
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; i < NSEG; i++ )
{
plcol0( i % 2 + 1 );
plarc( 0.0, 0.0, 8.0, 8.0, theta, theta + dtheta, 0.0, 0 );
theta = theta + dtheta;
}
// 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; i < NSEG; i++ )
{
plcol0( 2 - 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;
}
}
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