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| 1 | --[[ $Id: x03.lua 10613 2009-11-19 12:05:09Z andrewross $ |
| 2 | |
| 3 | Polar plot demo. |
| 4 | |
| 5 | Copyright (C) 2008 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 | -- main |
| 29 | -- |
| 30 | -- Generates polar plot, with 1-1 scaling. |
| 31 | ---------------------------------------------------------------------------- |
| 32 | |
| 33 | x0 = {} |
| 34 | y0 = {} |
| 35 | x = {} |
| 36 | y = {} |
| 37 | |
| 38 | dtr = math.pi/180 |
| 39 | for i = 1, 361 do |
| 40 | x0[i] = math.cos(dtr * (i-1)) |
| 41 | y0[i] = math.sin(dtr * (i-1)) |
| 42 | end |
| 43 | |
| 44 | -- Parse and process command line arguments |
| 45 | |
| 46 | pl.parseopts(arg, pl.PL_PARSE_FULL) |
| 47 | |
| 48 | -- Set orientation to portrait - note not all device drivers |
| 49 | -- support this, in particular most interactive drivers do not |
| 50 | pl.sori(1) |
| 51 | |
| 52 | -- Initialize plplot |
| 53 | pl.init() |
| 54 | |
| 55 | -- Set up viewport and window, but do not draw box |
| 56 | pl.env(-1.3, 1.3, -1.3, 1.3, 1, -2) |
| 57 | |
| 58 | -- Draw circles for polar grid |
| 59 | for i = 1, 10 do |
| 60 | pl.arc(0, 0, 0.1*i, 0.1*i, 0, 360, 0); |
| 61 | end |
| 62 | |
| 63 | pl.col0(2) |
| 64 | for i=1, 12 do |
| 65 | theta = 30 * (i-1) |
| 66 | dx = math.cos(dtr * theta) |
| 67 | dy = math.sin(dtr * theta) |
| 68 | |
| 69 | -- Draw radial spokes for polar grid |
| 70 | |
| 71 | pl.join(0, 0, dx, dy) |
| 72 | |
| 73 | -- Write labels for angle |
| 74 | if theta < 9.99 then |
| 75 | offset = 0.45 |
| 76 | else |
| 77 | if theta < 99.9 then |
| 78 | offset = 0.30 |
| 79 | else |
| 80 | offset = 0.15 |
| 81 | end |
| 82 | end |
| 83 | |
| 84 | -- Slightly off zero to avoid floating point logic flips at 90 and 270 deg. |
| 85 | if dx >= -0.00001 then |
| 86 | pl.ptex(dx, dy, dx, dy, -offset, tostring(math.floor(theta))) |
| 87 | else |
| 88 | pl.ptex(dx, dy, -dx, -dy, 1.+offset, tostring(math.floor(theta))) |
| 89 | end |
| 90 | end |
| 91 | |
| 92 | -- Draw the graph |
| 93 | for i=1, 361 do |
| 94 | r = math.sin(dtr * (5*(i-1))) |
| 95 | x[i] = x0[i] * r |
| 96 | y[i] = y0[i] * r |
| 97 | end |
| 98 | pl.col0(3) |
| 99 | pl.line(x, y) |
| 100 | |
| 101 | pl.col0(4) |
| 102 | pl.mtex("t", 2, 0.5, 0.5, "#frPLplot Example 3 - r(#gh)=sin 5#gh") |
| 103 | |
| 104 | -- Close the plot at end |
| 105 | pl.plend() |
| 106 |
