info.c

Go to the documentation of this file.

/*************************************************************************
 * Copyright (c) 2011 AT&T Intellectual Property 
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors: Details at https://graphviz.org
 *************************************************************************/
 
#include <neatogen/neato.h>
#include <stdio.h>
#include <neatogen/mem.h>
#include <neatogen/info.h>
 
 
Info_t *nodeInfo;               /* Array of node info */
static Freelist pfl;
 
void infoinit(void)
{
    freeinit(&pfl, sizeof(PtItem));
}
 
/* compare:
 * returns -1 if p < q
 *          0 if p = q
 *          1 if p > q
 * if q if NULL, returns -1
 * Ordering is by angle from -pi/2 to 3pi/4.
 * For equal angles (which should not happen in our context)
 * ordering is by closeness to origin.
 */
static int compare(Point * o, PtItem * p, PtItem * q)
{
    double x0;
    double y0;
    double x1;
    double y1;
    double a, b;
 
    if (q == NULL)
        return -1;
    if (p->p.x == q->p.x && p->p.y == q->p.y)
        return 0;
 
    x0 = (double)p->p.x - (double)o->x;
    y0 = (double)p->p.y - (double)o->y;
    x1 = (double)q->p.x - (double)o->x;
    y1 = (double)q->p.y - (double)o->y;
    if (x0 >= 0.0) {
        if (x1 < 0.0)
            return -1;
        else if (x0 > 0.0) {
            if (x1 > 0.0) {
                a = y1 / x1;
                b = y0 / x0;
                if (b < a)
                    return -1;
                else if (b > a)
                    return 1;
                else if (x0 < x1)
                    return -1;
                else
                    return 1;
            } else {            /* x1 == 0.0 */
                if (y1 > 0.0)
                    return -1;
                else
                    return 1;
            }
        } else {                /* x0 == 0.0 */
            if (x1 > 0.0) {
                if (y0 <= 0.0)
                    return -1;
                else
                    return 1;
            } else {            /* x1 == 0.0 */
                if (y0 < y1) {
                    if (y1 <= 0.0)
                        return 1;
                    else
                        return -1;
                } else {
                    if (y0 <= 0.0)
                        return -1;
                    else
                        return 1;
                }
            }
        }
    } else {
        if (x1 >= 0.0)
            return 1;
        else {
            a = y1 / x1;
            b = y0 / x0;
            if (b < a)
                return -1;
            else if (b > a)
                return 1;
            else if (x0 > x1)
                return -1;
            else
                return 1;
        }
    }
}
 
void addVertex(Site * s, double x, double y)
{
    Info_t *ip;
    PtItem *p;
    PtItem *curr;
    PtItem *prev;
    Point *origin_point = &s->coord;
    PtItem tmp;
    int cmp;
 
    ip = nodeInfo + s->sitenbr;
    curr = ip->verts;
 
    tmp.p.x = x;
    tmp.p.y = y;
 
    cmp = compare(origin_point, &tmp, curr);
    if (cmp == 0)
        return;
    else if (cmp < 0) {
        p = getfree(&pfl);
        p->p.x = x;
        p->p.y = y;
        p->next = curr;
        ip->verts = p;
        return;
    }
 
    prev = curr;
    curr = curr->next;
    while ((cmp = compare(origin_point, &tmp, curr)) > 0) {
        prev = curr;
        curr = curr->next;
    }
    if (cmp == 0)
        return;
    p = getfree(&pfl);
    p->p.x = x;
    p->p.y = y;
    prev->next = p;
    p->next = curr;
}