// C-curve.c

#include <stdio.h>
#include <plot.h>
#define MAXORDER 13

void draw_c_curve (plPlotter *plotter, double dx, double dy, int order)
{
	if (order >= MAXORDER)
		/* continue path along (dx, dy) */
		pl_fcontrel_r (plotter, dx, dy);
	else
	{
		draw_c_curve (plotter,
				0.5 * (dx - dy), 0.5 * (dx + dy), order + 1);
		draw_c_curve (plotter,
				0.5 * (dx + dy), 0.5 * (dy - dx), order + 1);
	}
}

int main ()
{
	plPlotter *plotter;
	plPlotterParams *plotter_params;

	/* set a Plotter parameter */
	plotter_params = pl_newplparams ();
	pl_setplparam (plotter_params, "PAGESIZE", "letter");

      /* `X' -- X-window, change to `ps' -- write Postscript
          file to stdout
      */
	if ((plotter = pl_newpl_r ("X", stdin, stdout, stderr,
					plotter_params)) == NULL)
	{
		fprintf (stderr, "Couldn't create Plotter\n");
		return 1;
	}

	if (pl_openpl_r (plotter) < 0)      /* open Plotter */
	{
		fprintf (stderr, "Couldn't open Plotter\n");
		return 1;
	}
	pl_fspace_r (plotter, 0.0, 0.0, 1000.0, 1000.0); /* set coor system */
	pl_flinewidth_r (plotter, 0.25);    /* set line thickness */
	pl_pencolorname_r (plotter, "red"); /* use red pen */
	pl_erase_r (plotter);               /* erase graphics display */
	pl_fmove_r (plotter, 600.0, 300.0); /* position the graphics cursor */
	pl_fontname_r(plotter, "hersheysans");
	pl_alabel_r (plotter,'l', 'x', "this is\\spa\\ep label!!!");
	draw_c_curve (plotter, 0.0, 400.0, 0);
	if (pl_closepl_r (plotter) < 0)     /* close Plotter */
	{
		fprintf (stderr, "Couldn't close Plotter\n");
		return 1;
	}

	if (pl_deletepl_r (plotter) < 0)    /* delete Plotter */
	{
		fprintf (stderr, "Couldn't delete Plotter\n");
		return 1;
	}
	return 0;
}

# Makefile
LIB=/usr/X11R6/lib/
curve: C-curve.o
	gcc -o curve C-curve.o -L$(LIB) -lplot -lXaw -lXmu -lXt -lXext -lX11 -lpng -lz -lm
C-curve.o: C-curve.c
	gcc -c C-curve.c


clean:
	rm -f *.o curve