chtype.c

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/*!
   \file vector/vedit/chtype.c
 
   \brief Vedit library - change primitives type
 
   (C) 2008 by the GRASS Development Team
 
   This program is free software under the GNU General Public License
   (>=v2).  Read the file COPYING that comes with GRASS for details.
 
   \author Martin Landa <landa.martin gmail.com>
 */
 
#include <grass/vedit.h>
 
/*!
   \brief Change primitive type
 
   Supported conversions:
   - point <-> centroid
   - line <-> boundary
 
   \param Map pointer to Map_info
   \param List list of selected primitives
 
   \return number of modified primitives
   \return -1 on error
 */
int Vedit_chtype_lines(struct Map_info *Map, struct ilist *List)
{
    int i;
    int nret, line;
    int type, newtype;
    struct line_pnts *Points;
    struct line_cats *Cats;
 
    nret = 0;
 
    Points = Vect_new_line_struct();
    Cats = Vect_new_cats_struct();
 
    for (i = 0; i < List->n_values; i++) {
        line = List->value[i];
        if (!Vect_line_alive(Map, line))
            continue;
        type = Vect_read_line(Map, Points, Cats, line);
        if (type < 0) {
            return -1;
        }
        switch (type) {
        case GV_POINT:
            newtype = GV_CENTROID;
            break;
        case GV_CENTROID:
            newtype = GV_POINT;
            break;
        case GV_LINE:
            newtype = GV_BOUNDARY;
            break;
        case GV_BOUNDARY:
            newtype = GV_LINE;
            break;
        default:
            newtype = -1;
            break;
        }
 
        G_debug(3, "Vedit_chtype_lines(): line=%d, from_type=%d, to_type=%d",
                line, type, newtype);
 
        if (newtype > 0) {
            if (Vect_rewrite_line(Map, line, newtype, Points, Cats) < 0) {
                return -1;
            }
            nret++;
        }
    }
 
    Vect_destroy_line_struct(Points);
    Vect_destroy_cats_struct(Cats);
 
    return nret;
}