#! /usr/bin/env perl
#
# Demo x04 for the PLplot PDL binding
#
# Log plot demo
# (inspired from t/x04.t of module Graphics::PLplot, by Tim Jenness)
#
# Copyright (C) 2004 Rafael Laboissiere
#
# 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
# SYNC: x04c.c 1.17
use PDL;
use PDL::Graphics::PLplot;
use Math::Trig qw [pi];
# Parse and process command line arguments
plParseOpts (\@ARGV, PL_PARSE_SKIP | PL_PARSE_NOPROGRAM);
# Initialize plplot
plinit ();
plfont (2);
&plot1 (0);
&plot1 (1);
plend ();
sub plot1 {
my $type = shift;
pladv (0);
# Set up data for log plot
my $f0 = 1.0;
my ($freql, $ampl, $phase);
my $i = sequence (101);
$freql = -2.0 + $i / 20.0;
my $freq = 10 ** $freql;
$ampl = 20 * log10 (1 / sqrt (1 + ($freq / $f0) ** 2 ));
$phase = -(180/pi) * atan2 ($freq, $f0);
plvpor (0.15, 0.85, 0.1, 0.9);
plwind (-2, 3, -80, 0);
# Try different axis and labelling styles
plcol0 (1);
if ($type == 0) {
plbox (0, 0, 0, 0, "bclnst", "bnstv");
} else {
plbox (0, 0, 0, 0, "bcfghlnst", "bcghnstv");
}
# Plot ampl vs freq
plcol0 (2);
plline ($freql, $ampl);
plcol0 (2);
plptex (1.6, -30, 1, -20, 0.5, "-20 dB/decade");
# Put labels on
plcol0 (1);
plmtex (3.2, 0.5, 0.5, "b", "Frequency");
plmtex (2, 0.5, 0.5, "t", "Single Pole Low-Pass Filter");
plcol0 (2);
plmtex (5, 0.5, 0.5, "l", "Amplitude (dB)");
my $nlegend = 1;
# For the gridless case, put phase vs freq on same plot
if ($type == 0) {
plcol0 (1);
plwind (-2, 3, -100, 0);
plbox (0, 0, 30, 3, "", "cmstv");
plcol0 (3);
plline ($freql, $phase);
plstring($freql, $phase, "*");
plcol0 (3);
plmtex (5, 0.5, 0.5, "r", "Phase shift (degrees)");
$nlegend = 2;
}
# Draw a legend
my @opt_array = (PL_LEGEND_LINE, PL_LEGEND_LINE | PL_LEGEND_SYMBOL);
my @text_colors = (2, 3);
my @text = ("Amplitude", "Phase shift");
my @line_colors = (2, 3);
my @line_styles = (1, 1);
my @line_widths = (1, 1);
my @symbol_colors = (3, 3); # ???
my @symbol_scales = (1, 1); # ???
my @symbol_numbers = (4, 4);# ???
my @symbols = ('*', '*'); # ???
plscol0a(15, 32, 32, 32, 0.70);
my ($legend_width, $legend_height) = pllegend(
PL_LEGEND_BACKGROUND | PL_LEGEND_BOUNDING_BOX, 0,
0.0, 0.0, 0.1, 15,
1, 1, 0, 0,
$nlegend, \@opt_array,
1.0, 1.0, 2.0,
1., \@text_colors, \@text,
0, 0, 0, 0,
\@line_colors, \@line_styles, \@line_widths,
\@symbol_colors, \@symbol_scales, \@symbol_numbers, \@symbols);
}