libplplot-dev 5.10.0+dfsg2-0.1ubuntu2 / usr / share / doc / libplplot12 / examples / c / x17c.c

// $Id: x17c.c 12832 2013-12-09 14:39:59Z andrewross $
//
// Plots a simple stripchart with four pens.
//

#include "plcdemos.h"
#include <stdlib.h>
#ifdef PL_HAVE_NANOSLEEP
# include <time.h>
#endif
#ifdef PL_HAVE_UNISTD_H
# include <unistd.h>
#else
# ifdef PL_HAVE_POLL
#  include <poll.h>
# endif
#endif



// Variables for holding error return info from PLplot

static PLINT pl_errcode;
static char  errmsg[160];

//--------------------------------------------------------------------------
// main program
//--------------------------------------------------------------------------

int
main( int argc, const char *argv[] )
{
    PLINT           id1, n, autoy, acc, nsteps = 1000;
    PLFLT           y1, y2, y3, y4, ymin, ymax, xlab, ylab;
    PLFLT           t, tmin, tmax, tjump, dt, noise;
    PLINT           colbox, collab, colline[4], styline[4];
    const char      *legline[4];
#ifdef PL_HAVE_NANOSLEEP
    struct timespec ts;
#endif

// plplot initialization
// Parse and process command line arguments

    (void) plparseopts( &argc, argv, PL_PARSE_FULL );

// If db is used the plot is much more smooth. However, because of the
// async X behaviour, one does not have a real-time scripcharter.
// This is now disabled since it does not significantly improve the
// performance on new machines and makes it difficult to use this
// example non-interactively since it requires an extra pleop call after
// each call to plstripa.
//
    //plsetopt("db", "");
    //plsetopt("np", "");

// User sets up plot completely except for window and data
// Eventually settings in place when strip chart is created will be
// remembered so that multiple strip charts can be used simultaneously.
//

// Specify some reasonable defaults for ymin and ymax
// The plot will grow automatically if needed (but not shrink)

    ymin = -0.1;
    ymax = 0.1;

// Specify initial tmin and tmax -- this determines length of window.
// Also specify maximum jump in t
// This can accomodate adaptive timesteps

    tmin  = 0.;
    tmax  = 10.;
    tjump = 0.3;        // percentage of plot to jump

// Axes options same as plbox.
// Only automatic tick generation and label placement allowed
// Eventually I'll make this fancier

    colbox     = 1;
    collab     = 3;
    styline[0] = colline[0] = 2;        // pens color and line style
    styline[1] = colline[1] = 3;
    styline[2] = colline[2] = 4;
    styline[3] = colline[3] = 5;

    legline[0] = "sum";                         // pens legend
    legline[1] = "sin";
    legline[2] = "sin*noi";
    legline[3] = "sin+noi";

    xlab = 0.; ylab = 0.25;     // legend position

    autoy = 1;                  // autoscale y
    acc   = 1;                  // don't scrip, accumulate

// Initialize plplot

    plinit();

    pladv( 0 );
    plvsta();

// Register our error variables with PLplot
// From here on, we're handling all errors here

    plsError( &pl_errcode, errmsg );

    plstripc( &id1, "bcnst", "bcnstv",
        tmin, tmax, tjump, ymin, ymax,
        xlab, ylab,
        autoy, acc,
        colbox, collab,
        colline, styline, legline,
        "t", "", "Strip chart demo" );

    if ( pl_errcode )
    {
        fprintf( stderr, "%s\n", errmsg );
        exit( 1 );
    }

// Let plplot handle errors from here on

    plsError( NULL, NULL );

    autoy = 0;  // autoscale y
    acc   = 1;  // accumulate

// This is to represent a loop over time
// Let's try a random walk process

    y1 = y2 = y3 = y4 = 0.0;
    dt = 0.1;

#ifdef PL_HAVE_NANOSLEEP
    ts.tv_sec  = 0;
    ts.tv_nsec = 10000000;
#endif
    for ( n = 0; n < nsteps; n++ )
    {
#ifdef PL_HAVE_NANOSLEEP
        nanosleep( &ts, NULL );  // wait a little (10 ms) to simulate time elapsing
#else
# ifdef PL_HAVE_POLL
        poll( 0, 0, 10 );
# else
        { int i; for ( i = 0; i < 1000000; i++ )
              ;
        }
# endif
#endif
        t     = (double) n * dt;
        noise = plrandd() - 0.5;
        y1    = y1 + noise;
        y2    = sin( t * M_PI / 18. );
        y3    = y2 * noise;
        y4    = y2 + noise / 3.;

        // There is no need for all pens to have the same number of
        // points or beeing equally time spaced.

        if ( n % 2 )
            plstripa( id1, 0, t, y1 );
        if ( n % 3 )
            plstripa( id1, 1, t, y2 );
        if ( n % 4 )
            plstripa( id1, 2, t, y3 );
        if ( n % 5 )
            plstripa( id1, 3, t, y4 );

        // needed if using double buffering (-db on command line)
        //pleop();
    }

// Destroy strip chart and it's memory

    plstripd( id1 );
    plend();
    exit( 0 );
}