/* $Id: x17c.c,v 1.14 2001/06/07 22:07:17 airwin Exp $

 * Plots a simple stripchart with four pens.
 */

#include "plplot/plcdemos.h"
#ifdef HAS_POLL
#include <poll.h>
#else
#include <unistd.h>
#endif

/* Variables for holding error return info from PLplot */

static PLINT errcode;
static char errmsg[160];

/*--------------------------------------------------------------------------*\
 * main program
\*--------------------------------------------------------------------------*/

int
main(int argc, char *argv[])
{
    PLINT id1, id2, 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];
    char *legline[4], toplab[20];
    double drand48(void);

/* 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.
*/
    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(&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 (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;

    for (n = 0; n < nsteps; n++) {
#ifdef HAS_POLL
	poll(0,0,10);
#else
	usleep(10000);	/* wait a little (10 ms) to simulate time elapsing */
#endif
	t = (double)n * dt;
	noise = drand48() - 0.5;
	y1 = y1 + noise;
	y2 = sin(t*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);
	pleop();  /* use double buffer (-db on command line) */
    }

/* Destroy strip chart and it's memory */

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