Geografic-Information-System/vector/v.voronoi/vo_write.c

#include <stdio.h>
#include <math.h>
#include <float.h>
#include <grass/gis.h>
#include <grass/vector.h>
#include <grass/display.h>
#include "sw_defs.h"
#include "defs.h"
#include "write.h"

int write_ep(struct Edge *e)
{
    static struct line_pnts *Points = NULL;
    static struct line_cats *Cats = NULL;

    if (!Points) {
	Points = Vect_new_line_struct();
	Cats = Vect_new_cats_struct();
    }

    if (!triangulate) {
	double x1, y1, x2, y2;

	if (e->ep[le] != NULL && e->ep[re] != NULL) {	/* both end defined */
	    x1 = e->ep[le]->coord.x;
	    y1 = e->ep[le]->coord.y;
	    x2 = e->ep[re]->coord.x;
	    y2 = e->ep[re]->coord.y;

	    if (!Vect_point_in_box(x1, y1, 0.0, &Box) ||
		!Vect_point_in_box(x2, y2, 0.0, &Box)) {
		Vect_box_clip(&x1, &y1, &x2, &y2, &Box);
	    }

	    /* Don't write zero length */
	    if (x1 == x2 && y1 == y2)
		return 0;

	    Vect_reset_line(Points);
	    Vect_append_point(Points, x1, y1, 0.0);
	    Vect_append_point(Points, x2, y2, 0.0);
	    Vect_write_line(&Out, Type, Points, Cats);
	}
	else {
	    int knownPointAtLeft;

	    if (e->ep[le] != NULL) {
		x1 = e->ep[le]->coord.x;
		y1 = e->ep[le]->coord.y;
		knownPointAtLeft = 1;
	    }
	    else {
		x1 = e->ep[re]->coord.x;
		y1 = e->ep[re]->coord.y;
		knownPointAtLeft = 0;
	    }

	    if (extend_line(Box.S, Box.N, Box.W, Box.E,
			    e->a, e->b, e->c, x1, y1, &x2, &y2,
			    knownPointAtLeft)
		) {
		/* Don't write zero length */
		if (x1 == x2 && y1 == y2)
		    return 0;

		Vect_reset_line(Points);
		Vect_append_point(Points, x1, y1, 0.0);
		Vect_append_point(Points, x2, y2, 0.0);
		Vect_write_line(&Out, Type, Points, Cats);
	    }
	}
    }

    return 0;
}