// -*- coding: utf-8; -*-
//
// $Id: x26c.c 12319 2013-05-01 21:51:24Z airwin $
//
// Multi-lingual version of the first page of example 4.
//
// Copyright (C) 2006 Alan Irwin
// Copyright (C) 2006 Andrew Ross
//
// Thanks to the following for providing translated strings for this example:
// Valery Pipin (Russian)
//
// 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
//
//
//
// This example designed just for devices (e.g., psttfc and the
// cairo-related devices) that use the pango and fontconfig libraries. The
// best choice of glyph is selected by fontconfig and automatically rendered
// by pango in way that is sensitive to complex text layout (CTL) language
// issues for each unicode character in this example. Of course, you must
// have the appropriate TrueType fonts installed to have access to all the
// required glyphs.
//
// Translation instructions: The strings to be translated are given by
// x_label, y_label, alty_label, title_label, and line_label below. The
// encoding used must be UTF-8.
//
// The following strings to be translated involve some scientific/mathematical
// jargon which is now discussed further to help translators.
//
// (1) dB is a decibel unit, see http://en.wikipedia.org/wiki/Decibel .
// (2) degrees is an angular measure, see
// http://en.wikipedia.org/wiki/Degree_(angle) .
// (3) low-pass filter is one that transmits (passes) low frequencies.
// (4) pole is in the mathematical sense, see
// http://en.wikipedia.org/wiki/Pole_(complex_analysis) . "Single Pole"
// means a particular mathematical transformation of the filter function has
// a single pole, see
// http://ccrma.stanford.edu/~jos/filters/Pole_Zero_Analysis_I.html .
// Furthermore, a single-pole filter must have an inverse square decline
// (or -20 db/decade). Since the filter plotted here does have that
// characteristic, it must by definition be a single-pole filter, see also
// http://www-k.ext.ti.com/SRVS/Data/ti/KnowledgeBases/analog/document/faqs/1p.htm
// (5) decade represents a factor of 10, see
// http://en.wikipedia.org/wiki/Decade_(log_scale) .
//
#include "plcdemos.h"
static const char *x_labels[] = {
"Frequency",
"Частота",
NULL
};
static const char *y_labels[] = {
"Amplitude (dB)",
"Амплитуда (dB)",
NULL
};
static const char *alty_labels[] = {
"Phase shift (degrees)",
"Фазовый сдвиг (градусы)",
NULL
};
// Short rearranged versions of y_label and alty_label.
static const char *legend_texts[][2] = {
{ "Amplitude", "Phase shift" },
{ "Амплитуда", "Фазовый сдвиг" }
};
static const char *title_labels[] = {
"Single Pole Low-Pass Filter",
"Однополюсный Низко-Частотный Фильтр",
NULL
};
static const char *line_labels[] = {
"-20 dB/decade",
"-20 dB/десяток",
NULL
};
void plot1( int type, const char *x_label, const char *y_label,
const char *alty_label, const char * legend_text[],
const char *title_label, const char *line_label );
//--------------------------------------------------------------------------
// main
//
// Illustration of logarithmic axes, and redefinition of window.
//--------------------------------------------------------------------------
int
main( int argc, const char *argv[] )
{
int i;
// Parse and process command line arguments
(void) plparseopts( &argc, argv, PL_PARSE_FULL );
// Initialize plplot
plinit();
plfont( 2 );
// Make log plots using two different styles.
i = 0;
while ( x_labels[i] != NULL )
{
plot1( 0, x_labels[i], y_labels[i], alty_labels[i],
legend_texts[i], title_labels[i], line_labels[i] );
i++;
}
plend();
exit( 0 );
}
//--------------------------------------------------------------------------
// plot1
//
// Log-linear plot.
//--------------------------------------------------------------------------
void
plot1( int type, const char *x_label, const char *y_label, const char *alty_label,
const char * legend_text[], const char *title_label, const char *line_label )
{
int i;
static PLFLT freql[101], ampl[101], phase[101];
PLFLT f0, freq;
PLINT nlegend = 2;
PLINT opt_array[2];
PLINT text_colors[2];
PLINT line_colors[2];
PLINT line_styles[2];
PLFLT line_widths[2];
PLINT symbol_numbers[2], symbol_colors[2];
PLFLT symbol_scales[2];
const char *symbols[2];
PLFLT legend_width, legend_height;
pladv( 0 );
// Set up data for log plot
f0 = 1.0;
for ( i = 0; i <= 100; i++ )
{
freql[i] = -2.0 + i / 20.0;
freq = pow( 10.0, freql[i] );
ampl[i] = 20.0 * log10( 1.0 / sqrt( 1.0 + pow( ( freq / f0 ), 2. ) ) );
phase[i] = -( 180.0 / M_PI ) * atan( freq / f0 );
}
plvpor( 0.15, 0.85, 0.1, 0.9 );
plwind( -2.0, 3.0, -80.0, 0.0 );
// Try different axis and labelling styles.
plcol0( 1 );
switch ( type )
{
case 0:
plbox( "bclnst", 0.0, 0, "bnstv", 0.0, 0 );
break;
case 1:
plbox( "bcfghlnst", 0.0, 0, "bcghnstv", 0.0, 0 );
break;
}
// Plot ampl vs freq
plcol0( 2 );
plline( 101, freql, ampl );
plcol0( 2 );
plptex( 1.6, -30.0, 1.0, -20.0, 0.5, line_label );
// Put labels on
plcol0( 1 );
plmtex( "b", 3.2, 0.5, 0.5, x_label );
plmtex( "t", 2.0, 0.5, 0.5, title_label );
plcol0( 2 );
plmtex( "l", 5.0, 0.5, 0.5, y_label );
// For the gridless case, put phase vs freq on same plot
if ( type == 0 )
{
plcol0( 1 );
plwind( -2.0, 3.0, -100.0, 0.0 );
plbox( "", 0.0, 0, "cmstv", 30.0, 3 );
plcol0( 3 );
plline( 101, freql, phase );
plstring( 101, freql, phase, "*" );
plcol0( 3 );
plmtex( "r", 5.0, 0.5, 0.5, alty_label );
}
// Draw a legend
// First legend entry.
opt_array[0] = PL_LEGEND_LINE;
text_colors[0] = 2;
line_colors[0] = 2;
line_styles[0] = 1;
line_widths[0] = 1.;
// note from the above opt_array the first symbol (and box) indices
// do not have to be specified
// Second legend entry.
opt_array[1] = PL_LEGEND_LINE | PL_LEGEND_SYMBOL;
text_colors[1] = 3;
line_colors[1] = 3;
line_styles[1] = 1;
line_widths[1] = 1.;
symbol_colors[1] = 3;
symbol_scales[1] = 1.;
symbol_numbers[1] = 4;
symbols[1] = "*";
// from the above opt_arrays we can completely ignore everything
// to do with boxes.
plscol0a( 15, 32, 32, 32, 0.70 );
pllegend( &legend_width, &legend_height,
PL_LEGEND_BACKGROUND | PL_LEGEND_BOUNDING_BOX, 0,
0.0, 0.0, 0.10, 15,
1, 1, 0, 0,
nlegend, opt_array,
1.0, 1.0, 2.0,
1., text_colors, (const char **) legend_text,
NULL, NULL, NULL, NULL,
line_colors, line_styles, line_widths,
symbol_colors, symbol_scales, symbol_numbers, (const char **) symbols );
}