libplplot-java 5.10.0+dfsg2-0.1ubuntu2 / usr / share / doc / libplplot12 / examples / java / x04.java

//--------------------------------------------------------------------------
// $Id: x04.java 12329 2013-05-02 22:44:50Z airwin $
//--------------------------------------------------------------------------

//--------------------------------------------------------------------------
// Copyright (C) 2001  Geoffrey Furnish
// Copyright (C) 2001, 2002  Alan W. Irwin
// Copyright (C) 2004  Andrew Ross
//
// 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; version 2 of the License.
//
// 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
//--------------------------------------------------------------------------

//--------------------------------------------------------------------------
// Implementation of PLplot example 4 in Java.
//--------------------------------------------------------------------------

package plplot.examples;

import plplot.core.*;
import static plplot.core.plplotjavacConstants.*;

import java.lang.Math;

class x04 {
    PLStream pls = new PLStream();

    public static void main( String[] args )
    {
        new x04( args );
    }

    public x04( String[] args )
    {
        // Parse and process command line arguments.

        pls.parseopts( args, PL_PARSE_FULL | PL_PARSE_NOPROGRAM );

        // Initialize plplot.

        pls.init();
        pls.font( 2 );

        // Make log plots using two different styles.

        plot1( 0 );
        plot1( 1 );

        pls.end();
    }

// Log-linear plot.

    void plot1( int type )
    {
        int i;
        double[] freql = new double[101];
        double[] ampl  = new double[101];
        double[] phase = new double[101];
        double f0, freq;
        int    nlegend;
        String[] text;
        String[] symbols;
        int[] opt_array;
        int[] text_colors;
        int[] line_colors;
        int[] line_styles;
        double[] line_widths;
        int[] symbol_numbers;
        int[] symbol_colors;
        double[] symbol_scales;
        double[] legend_width  = new double[1];
        double[] legend_height = new double[1];

        pls.adv( 0 );

        // Set up data for log plot.

        f0 = 1.0;
        for ( i = 0; i <= 100; i++ )
        {
            freql[i] = -2.0 + i / 20.0;
            freq     = Math.pow( 10.0, freql[i] );
            // Unbelievably, Java has no log10() that I can find...
            ampl[i]  = 20.0 * Math.log( 1.0 / Math.sqrt( 1.0 + Math.pow( ( freq / f0 ), 2. ) ) ) / Math.log( 10. );
            phase[i] = -( 180.0 / Math.PI ) * Math.atan( freq / f0 );
        }

        pls.vpor( 0.15, 0.85, 0.1, 0.9 );
        pls.wind( -2.0, 3.0, -80.0, 0.0 );

        // Try different axis and labelling styles.

        pls.col0( 1 );
        switch ( type )
        {
        case 0:
            pls.box( "bclnst", 0.0, 0, "bnstv", 0.0, 0 );
            break;
        case 1:
            pls.box( "bcfghlnst", 0.0, 0, "bcghnstv", 0.0, 0 );
            break;
        }

        // Plot ampl vs freq.

        pls.col0( 2 );
        pls.line( freql, ampl );
        pls.col0( 2 );
        pls.ptex( 1.6, -30.0, 1.0, -20.0, 0.5, "-20 dB/decade" );

        // Put labels on.

        pls.col0( 1 );
        pls.mtex( "b", 3.2, 0.5, 0.5, "Frequency" );
        pls.mtex( "t", 2.0, 0.5, 0.5, "Single Pole Low-Pass Filter" );
        pls.col0( 2 );
        pls.mtex( "l", 5.0, 0.5, 0.5, "Amplitude (dB)" );
        nlegend = 1;

        // For the gridless case, put phase vs freq on same plot.

        if ( type == 0 )
        {
            pls.col0( 1 );
            pls.wind( -2.0, 3.0, -100.0, 0.0 );
            pls.box( "", 0.0, 0, "cmstv", 30.0, 3 );
            pls.col0( 3 );
            pls.line( freql, phase );
            pls.string( freql, phase, "*" );
            pls.col0( 3 );
            pls.mtex( "r", 5.0, 0.5, 0.5, "Phase shift (degrees)" );
            nlegend = 2;
        }
        text           = new String[nlegend];
        symbols        = new String[nlegend];
        opt_array      = new int[nlegend];
        text_colors    = new int[nlegend];
        line_colors    = new int[nlegend];
        line_styles    = new int[nlegend];
        line_widths    = new double[nlegend];
        symbol_numbers = new int[nlegend];
        symbol_colors  = new int[nlegend];
        symbol_scales  = new double[nlegend];

        // Draw a legend
        // First legend entry.
        opt_array[0]   = PL_LEGEND_LINE;
        text_colors[0] = 2;
        text[0]        = "Amplitude";
        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 EXCEPT for symbols.
        // Although this is unused, it can't be undefined as the String
        // array is copied as part of the java bindings.
        symbols[0] = " ";

        // Second legend entry.
        if ( nlegend == 2 )
        {
            opt_array[1]      = PL_LEGEND_LINE | PL_LEGEND_SYMBOL;
            text_colors[1]    = 3;
            text[1]           = "Phase shift";
            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.

        pls.scol0a( 15, 32, 32, 32, 0.70 );
        pls.legend( legend_width, legend_height,
            PL_LEGEND_BACKGROUND | 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,
            null, null, null, null,
            line_colors, line_styles, line_widths,
            symbol_colors, symbol_scales, symbol_numbers, symbols );
    }
}

//--------------------------------------------------------------------------
//                              End of x04.java
//--------------------------------------------------------------------------