/usr/share/doc/libplplot12/examples/lua/x04.lua is in libplplot-dev 5.10.0+dfsg-1.
This file is owned by root:root, with mode 0o644.
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Log plot demo.
Simple line plot and multiple windows 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 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
--]]
-- initialise Lua bindings for PLplot examples.
dofile("plplot_examples.lua")
----------------------------------------------------------------------------
-- plot1
--
-- Log-linear plot.
----------------------------------------------------------------------------
-- return single bit (for OR)
function bit(x,b)
return ((x % 2^b) - (x % 2^(b-1)) > 0)
end
-- logic OR for number values
function lor(x,y)
result = 0
for p=1,8 do result = result + (((bit(x,p) or bit(y,p)) == true) and 2^(p-1) or 0) end
return result
end
function plot1(type)
freql = {}
ampl = {}
phase = {}
pl.adv(0)
-- Set up data for log plot
f0 = 1
for i=1, 101 do
freql[i] = -2 + (i-1) / 20
freq = 10^freql[i]
ampl[i] = 20 * math.log10(1 / math.sqrt(1 + (freq / f0)^2))
phase[i] = -(180 / math.pi) * math.atan(freq / f0)
end
pl.vpor(0.15, 0.85, 0.1, 0.9)
pl.wind(-2, 3, -80, 0)
-- Try different axis and labelling styles.
pl.col0(1)
if type == 0 then
pl.box("bclnst", 0, 0, "bnstv", 0, 0)
elseif type == 1 then
pl.box("bcfghlnst", 0, 0, "bcghnstv", 0, 0)
else
print("error: type must be either 0 or 1")
end
-- Plot ampl vs freq
pl.col0(2)
pl.line(freql, ampl)
pl.col0(2)
pl.ptex(1.6, -30, 1, -20, 0.5, "-20 dB/decade")
-- Put labels on
pl.col0(1)
pl.mtex("b", 3.2, 0.5, 0.5, "Frequency")
pl.mtex("t", 2, 0.5, 0.5, "Single Pole Low-Pass Filter")
pl.col0(2)
pl.mtex("l", 5, 0.5, 0.5, "Amplitude (dB)")
-- For the gridless case, put phase vs freq on same plot
if type == 0 then
pl.col0(1)
pl.wind(-2, 3, -100, 0)
pl.box("", 0, 0, "cmstv", 30, 3)
pl.col0(3)
pl.line(freql, phase)
pl.string(freql, phase, "*")
pl.col0(3)
pl.mtex("r", 5, 0.5, 0.5, "Phase shift (degrees)")
nlegend = 2
else
nlegend = 1
end
-- Draw a legend.
opt_array = {}
text_colors = {}
text = {}
box_colors = {}
box_patterns = {}
box_scales = {}
box_line_widths = {}
line_colors = {}
line_styles = {}
line_widths = {}
symbol_colors = {}
symbol_scales = {}
symbol_numbers = {}
symbols = {}
-- Data for the first legend entry.
opt_array[1] = pl.PL_LEGEND_LINE
text_colors[1] = 2
text[1] = "Amplitude"
-- box data unused so initialize to arbitrary values.
box_colors[1] = 0
box_patterns[1] = 0
box_scales[1] = 0
box_line_widths[1] = 0.
line_colors[1] = 2
line_styles[1] = 1
line_widths[1] = 1.
-- unused arbitrary data
symbol_colors[1] = 0
symbol_scales[1] = 0
symbol_numbers[1] = 0
symbols[1] = ""
-- Data for the second legend entry.
if nlegend > 1 then
opt_array[2] = lor(pl.PL_LEGEND_LINE, pl.PL_LEGEND_SYMBOL)
text_colors[2] = 3
text[2] = "Phase shift"
-- box data unused so initialize to arbitrary values.
box_colors[2] = 0
box_patterns[2] = 0
box_scales[2] = 0
box_line_widths[2] = 0.
line_colors[2] = 3
line_styles[2] = 1
line_widths[2] = 1.
symbol_colors[2] = 3
symbol_scales[2] = 1.
symbol_numbers[2] = 4
symbols[2] = "*"
end
pl.scol0a( 15, 32, 32, 32, 0.70 )
legend_width, legend_height = pl.legend(
lor(pl.PL_LEGEND_BACKGROUND, pl.PL_LEGEND_BOUNDING_BOX), 0, 0.0, 0.0,
0.1, 15, 1, 1, 0, 0, opt_array, 1.0, 1.0, 2.0,
1., text_colors, text,
box_colors, box_patterns, box_scales, box_line_widths,
line_colors, line_styles, line_widths,
symbol_colors, symbol_scales, symbol_numbers, symbols )
end
----------------------------------------------------------------------------
-- main
--
-- Illustration of logarithmic axes, and redefinition of window.
----------------------------------------------------------------------------
-- Parse and process command line arguments
pl.parseopts(arg, pl.PL_PARSE_FULL)
-- Initialize plplot
pl.init()
pl.font(2)
-- Make log plots using two different styles.
plot1(0)
plot1(1)
pl.plend()
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