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Source at commit 868eb3b created 13 years 1 month ago. By Xiangfu Liu, rename nanonote-example files | |
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1 | --[[ $Id: x27.lua 9526 2009-02-13 22:06:13Z smekal $ |
2 | |
3 | Drawing "spirograph" curves - epitrochoids, cycolids, roulettes |
4 | |
5 | Copyright (C) 2009 Werner Smekal |
6 | |
7 | This file is part of PLplot. |
8 | |
9 | PLplot is free software you can redistribute it and/or modify |
10 | it under the terms of the GNU General Library Public License as published |
11 | by the Free Software Foundation either version 2 of the License, or |
12 | (at your option) any later version. |
13 | |
14 | PLplot is distributed in the hope that it will be useful, |
15 | but WITHOUT ANY WARRANTY without even the implied warranty of |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
17 | GNU Library General Public License for more details. |
18 | |
19 | You should have received a copy of the GNU Library General Public License |
20 | along with PLplot if not, write to the Free Software |
21 | Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
22 | --]] |
23 | |
24 | -- initialise Lua bindings for PLplot examples. |
25 | dofile("plplot_examples.lua") |
26 | |
27 | |
28 | function cycloid() |
29 | -- TODO |
30 | end |
31 | |
32 | |
33 | function spiro( params ) |
34 | NPNT = 20000 |
35 | xcoord = {} |
36 | ycoord = {} |
37 | |
38 | -- Fill the coordinates |
39 | windings = params[4] |
40 | steps = math.floor(NPNT/windings) |
41 | dphi = 8*math.acos(-1)/steps |
42 | |
43 | xmin = 0 -- This initialisation is safe! |
44 | xmax = 0 |
45 | ymin = 0 |
46 | ymax = 0 |
47 | |
48 | for i = 1, windings*steps+1 do |
49 | phi = (i-1) * dphi |
50 | phiw = (params[1]-params[2])/params[2]*phi |
51 | xcoord[i] = (params[1]-params[2])*math.cos(phi) + params[3]*math.cos(phiw) |
52 | ycoord[i] = (params[1]-params[2])*math.sin(phi) - params[3]*math.sin(phiw) |
53 | |
54 | if xmin>xcoord[i] then xmin = xcoord[i] end |
55 | if xmax<xcoord[i] then xmax = xcoord[i] end |
56 | if ymin>ycoord[i] then ymin = ycoord[i] end |
57 | if ymax<ycoord[i] then ymax = ycoord[i] end |
58 | end |
59 | |
60 | if (xmax-xmin)>(ymax-ymin) then |
61 | scale = xmax - xmin |
62 | else |
63 | scale = ymax - ymin |
64 | end |
65 | xmin = -0.65*scale |
66 | xmax = 0.65*scale |
67 | ymin = -0.65*scale |
68 | ymax = 0.65*scale |
69 | |
70 | pl.wind(xmin, xmax, ymin, ymax) |
71 | |
72 | pl.col0(1) |
73 | pl.line(xcoord, ycoord) |
74 | end |
75 | |
76 | |
77 | ---------------------------------------------------------------------------- |
78 | -- main |
79 | -- |
80 | -- Generates two kinds of plots: |
81 | -- - construction of a cycloid (animated) |
82 | -- - series of epitrochoids and hypotrochoids |
83 | ---------------------------------------------------------------------------- |
84 | |
85 | -- R, r, p, N |
86 | params = { |
87 | { 21, 7, 7, 3 }, -- Deltoid |
88 | { 21, 7, 10, 3 }, |
89 | { 21, -7, 10, 3 }, |
90 | { 20, 3, 7, 20 }, |
91 | { 20, 3, 10, 20 }, |
92 | { 20, -3, 10, 20 }, |
93 | { 20, 13, 7, 20 }, |
94 | { 20, 13, 20, 20 }, |
95 | { 20,-13, 20, 20 } } |
96 | |
97 | -- plplot initialization |
98 | |
99 | -- Parse and process command line arguments |
100 | pl.parseopts(arg, pl.PL_PARSE_FULL) |
101 | |
102 | -- Initialize plplot |
103 | pl.init() |
104 | |
105 | -- Illustrate the construction of a cycloid |
106 | cycloid() |
107 | |
108 | -- Loop over the various curves |
109 | -- First an overview, then all curves one by one |
110 | |
111 | pl.ssub(3, 3) -- Three by three window |
112 | |
113 | for i = 1, 9 do |
114 | pl.adv(0) |
115 | pl.vpor(0, 1, 0, 1) |
116 | spiro(params[i]) |
117 | end |
118 | |
119 | pl.adv(0) |
120 | pl.ssub(1, 1) -- One window per curve |
121 | |
122 | for i = 1, 9 do |
123 | pl.adv(0) |
124 | pl.vpor(0, 1, 0, 1) |
125 | spiro(params[i]) |
126 | end |
127 | |
128 | -- Don't forget to call plend() to finish off! |
129 | pl.plend() |
130 |