#include <stdio.h>
#include <math.h>
#include <g2.h>
#include <g2_X11.h>
#define PI 3.1415926
/* gcc g2_animation.c -lm -lg2 -lX11 */
/* simple animation trubasic style */
int n,m;
float x,dt,t,y,sx,sy,X0,Y0;

int main()
{
    int d;  /* a g2-object file handle */
    dt=0.01;
    /* open a 400 by 400 pixel window */
    /* lower left is (0,0), upper right is (400,400) */
    d=g2_open_X11(400, 400);
    /* draw a bounding box */
    g2_rectangle(d,4,4,396,396);
    /* draw in some coordinate axes */
    g2_line(d, 200,4, 200, 396); /* y axis */
    g2_line(d, 4, 200, 396, 200); /* x axis */
    /* draw tick-marks */
    for(n=1; n<20;n++){
	g2_line(d,20*n,196,20*n,204);
	g2_line(d,196,20*n,204,20*n);
    }
    /* create a curve, but scale it */
    g2_move(d,200,200); /* go to origin */
    sx=396.0/(2.0*PI); /* horizontal and vertical scale factors */
    sy=396.0/2.0;
    X0=0.0;
    Y0=0.0;
    for(n=0;n<628;n++){
	/* create an  x; 0 < x < 2PI */
	t=(float)n*dt;
	/* create Lissojou data */
	x=sin(3.0*t+PI/4.0);
	y=0.7*sin(5.0*t);
	/* map this into pixel interval from 0 to 400 */
     g2_pen(d,1);
    /* draw in some coordinate axes */
    g2_line(d, 200,4, 200, 396); /* y axis */
    g2_line(d, 4, 200, 396, 200); /* x axis */
    /* draw tick-marks */
    for(m=1; m<20;m++){
	g2_line(d,20*m,196,20*m,204);
	g2_line(d,196,20*m,204,20*m);
    }
    /* draw object as a circle */
        g2_circle(d,sx*x+200.0,sy*y+200.0, 5.0);
	g2_rectangle(d,4,4,396,396);
	g2_string(d,10,350,"A Lissojou figure");
	usleep(5000);
	g2_flush(d);
	/* erase the circle */
	g2_pen(d,0);
        g2_filled_circle(d,sx*x+200.0,sy*y+200.0, 6.0);
    }

    
    /* wait until a character is entered, then exit */
    getchar();
    g2_close(d);
    return 0;
}