/usr/share/doc/libplplot12/examples/ocaml/x27.ml is in libplplot-dev 5.10.0+dfsg-1.
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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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 | (* $Id: x27.ml 11855 2011-08-04 12:27:31Z hezekiahcarty $
Drawing "spirograph" curves - epitrochoids, cycolids, roulettes
Copyright (C) 2007 Arjen Markus
Copyright (C) 2008 Hezekiah M. Carty
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
*)
open Plplot
let pi = atan 1.0 *. 4.0
let cycloid () = () (* TODO *)
(* Calculate greatest common divisor following pseudo-code for the
Euclidian algorithm at http://en.wikipedia.org/wiki/Euclidean_algorithm *)
let rec gcd a b =
let a = abs a in
let b = abs b in
match b with
| 0 -> a
| _ -> gcd b (a mod b)
let spiro params fill =
let npnt = 2000 in
let xcoord = Array.make (npnt + 1) 0.0 in
let ycoord = Array.make (npnt + 1) 0.0 in
(* Fill the coordinates *)
(* Proper termination of the angle loop, very near the beginning
point, see
http://mathforum.org/mathimages/index.php/Hypotrochoid *)
let windings =
int_of_float (abs_float params.(1)) /
gcd (int_of_float params.(0)) (int_of_float params.(1))
in
let steps = npnt / windings in
let dphi = 2.0 *. pi /. float_of_int steps in
(* This initialisation appears to be necessary, but I (AWI) don't understand why! *)
let xmin = ref 0.0 in
let xmax = ref 0.0 in
let ymin = ref 0.0 in
let ymax = ref 0.0 in
for i = 0 to windings * steps do
let phi = float_of_int i *. dphi in
let phiw = (params.(0) -. params.(1)) /. params.(1) *. phi in
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 then (
xmin := xcoord.(i);
xmax := xcoord.(i);
ymin := ycoord.(i);
ymax := ycoord.(i);
)
else (
);
if !xmin > xcoord.(i) then xmin := xcoord.(i) else ();
if !xmax < xcoord.(i) then xmax := xcoord.(i) else ();
if !ymin > ycoord.(i) then ymin := ycoord.(i) else ();
if !ymax < ycoord.(i) then ymax := ycoord.(i) else ();
done;
let xrange_adjust = 0.15 *. (!xmax -. !xmin) in
let xmin = !xmin -. xrange_adjust in
let xmax = !xmax +. xrange_adjust in
let yrange_adjust = 0.15 *. (!ymax -. !ymin) in
let ymin = !ymin -. yrange_adjust in
let ymax = !ymax +. yrange_adjust in
plwind xmin xmax ymin ymax;
plcol0 1;
let xcoord' = Array.sub xcoord 0 (1 + steps * windings) in
let ycoord' = Array.sub ycoord 0 (1 + steps * windings) in
if fill then (
plfill xcoord' ycoord';
)
else (
plline xcoord' ycoord';
)
let deg_to_rad x = x *. pi /. 180.0
let arcs () =
let nseg = 8 in
let theta = ref 0.0 in
let dtheta = 360.0 /. float_of_int nseg in
plenv ~-.10.0 10.0 ~-.10.0 10.0 1 0;
(* Plot segments of circle in different colors *)
for i = 0 to nseg - 1 do
plcol0 (i mod 2 + 1);
plarc 0.0 0.0 8.0 8.0 !theta (!theta +. dtheta) 0.0 false;
theta := !theta +. dtheta;
done;
(* Draw several filled ellipses inside the circle at different
angles. *)
let a = 3.0 in
let b = a *. tan (deg_to_rad dtheta /. 2.0) in
theta := dtheta /. 2.0;
for i = 0 to nseg - 1 do
plcol0 (2 - i mod 2);
plarc (a *. cos (deg_to_rad !theta)) (a *. sin (deg_to_rad !theta)) a b 0.0 360.0 !theta true;
theta := !theta +. dtheta;
done;
()
(*--------------------------------------------------------------------------*\
* Generates two kinds of plots:
* - construction of a cycloid (animated)
* - series of epitrochoids and hypotrochoids
\*--------------------------------------------------------------------------*)
let () =
(* R, r, p, N *)
let 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|];
|]
in
(* plplot initialization *)
(* Parse and process command line arguments *)
plparseopts Sys.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 *)
(* Three by three window *)
plssub 3 3;
for i = 0 to 8 do
pladv 0;
plvpor 0.0 1.0 0.0 1.0;
spiro params.(i) false;
done;
pladv 0;
(* One window per curve *)
plssub 1 1;
for i = 0 to 8 do
pladv 0;
plvpor 0.0 1.0 0.0 1.0;
spiro params.(i) false;
done;
(* Fill the curves *)
pladv 0;
(* One window per curve *)
plssub 1 1;
for i = 0 to 8 do
pladv 0;
plvpor 0.0 1.0 0.0 1.0;
spiro params.(i) true;
done;
(* Finally, an example to test out plarc capabilities *)
arcs ();
(* Don't forget to call plend() to finish off! *)
plend ();
()
|