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openwrt-packages/nanonote-files/example-files/data/Examples/lua-plplot-examples/x03.lua

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2011-01-18 10:21:06 +02:00
--[[ $Id: x03.lua 10613 2009-11-19 12:05:09Z andrewross $
Polar plot demo.
Copyright (C) 2008 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 General Library 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
--]]
-- initialise Lua bindings for PLplot examples.
dofile("plplot_examples.lua")
----------------------------------------------------------------------------
-- main
--
-- Generates polar plot, with 1-1 scaling.
----------------------------------------------------------------------------
x0 = {}
y0 = {}
x = {}
y = {}
dtr = math.pi/180
for i = 1, 361 do
x0[i] = math.cos(dtr * (i-1))
y0[i] = math.sin(dtr * (i-1))
end
-- Parse and process command line arguments
pl.parseopts(arg, pl.PL_PARSE_FULL)
-- Set orientation to portrait - note not all device drivers
-- support this, in particular most interactive drivers do not
pl.sori(1)
-- Initialize plplot
pl.init()
-- Set up viewport and window, but do not draw box
pl.env(-1.3, 1.3, -1.3, 1.3, 1, -2)
-- Draw circles for polar grid
for i = 1, 10 do
pl.arc(0, 0, 0.1*i, 0.1*i, 0, 360, 0);
end
pl.col0(2)
for i=1, 12 do
theta = 30 * (i-1)
dx = math.cos(dtr * theta)
dy = math.sin(dtr * theta)
-- Draw radial spokes for polar grid
pl.join(0, 0, dx, dy)
-- Write labels for angle
if theta < 9.99 then
offset = 0.45
else
if theta < 99.9 then
offset = 0.30
else
offset = 0.15
end
end
-- Slightly off zero to avoid floating point logic flips at 90 and 270 deg.
if dx >= -0.00001 then
pl.ptex(dx, dy, dx, dy, -offset, tostring(math.floor(theta)))
else
pl.ptex(dx, dy, -dx, -dy, 1.+offset, tostring(math.floor(theta)))
end
end
-- Draw the graph
for i=1, 361 do
r = math.sin(dtr * (5*(i-1)))
x[i] = x0[i] * r
y[i] = y0[i] * r
end
pl.col0(3)
pl.line(x, y)
pl.col0(4)
pl.mtex("t", 2, 0.5, 0.5, "#frPLplot Example 3 - r(#gh)=sin 5#gh")
-- Close the plot at end
pl.plend()