vector/vedit/select.c

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/*!
   \file lib/vector/vedit/select.c
 
   \brief Vedit library - select primitives by query
 
   (C) 2007-2008 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 <math.h>
#include <grass/glocale.h>
#include <grass/vedit.h>
 
static int select_by_query(struct Map_info *, int, int, double, int,
                           struct line_pnts *, struct line_cats *);
 
static int merge_lists(struct ilist *alist, struct ilist *blist);
 
/*!
   \brief Select primitives by query (based on geometry properties)
 
   Currently supported:
   - QUERY_LENGTH, select all lines longer than threshold (or shorter if
   threshold is < 0)
   - QUERY_DANGLE, select all dangles longer than threshold (or shorter if
   threshold is < 0)
 
   Perform global query if <i>List</i> is empty otherwise query only
   selected vector objects.
 
   \param Map pointer to Map_info
   \param type feature type
   \param layer layer number (unused)
   \param thresh threshold value (< 0 for 'shorter', > 0 for 'longer')
   \param query query (length, dangle, ...)
   \param[in,out] List list of selected features
 
   \return number of selected primitives
 */
int Vedit_select_by_query(struct Map_info *Map, int type, int layer UNUSED,
                          double thresh, int query, struct ilist *List)
{
    int num, line, i;
    double thresh_tmp;
    struct line_pnts *Points;
    struct line_cats *Cats;
    struct ilist *List_query;
 
    Points = Vect_new_line_struct();
    Cats = Vect_new_cats_struct();
 
    if (List->n_values == 0) {
        List_query = List;
    }
    else {
        List_query = Vect_new_list();
    }
 
    switch (query) {
    case QUERY_LENGTH: {
        if (List->n_values == 0) {
            /* query all vector objects in vector map */
            num = Vect_get_num_lines(Map);
            for (line = 1; line <= num; line++) {
                if (select_by_query(Map, line, type, thresh, query, Points,
                                    Cats))
                    Vect_list_append(List_query, line);
            }
        }
        else {
            for (i = 0; i < List->n_values; i++) {
                line = List->value[i];
                if (select_by_query(Map, line, type, thresh, query, Points,
                                    Cats)) {
                    Vect_list_append(List_query, line);
                }
            }
        }
        break;
    }
    case QUERY_DANGLE: {
        struct ilist *List_dangle;
 
        List_dangle = Vect_new_list();
        thresh_tmp = fabs(thresh);
 
        /* select dangles shorter than 'thresh_tmp' */
        Vect_select_dangles(Map, type, thresh_tmp, List_dangle);
 
        if (thresh <= 0.0) { /* shorter than */
            for (i = 0; i < List_dangle->n_values; i++) {
                Vect_list_append(List_query, List_dangle->value[i]);
            }
        }
        else { /* longer than */
            for (i = 1; i <= Vect_get_num_lines(Map); i++) {
                if (!Vect_val_in_list(List_dangle, i))
                    Vect_list_append(List_query, i);
            }
        }
 
        Vect_destroy_list(List_dangle);
        break;
    }
    default:
        break;
    }
 
    if (List != List_query) {
        merge_lists(List, List_query);
        Vect_destroy_list(List_query);
    }
 
    G_debug(3, "Vedit_select_by_query(): %d lines selected (by query %d)",
            List->n_values, query);
 
    Vect_destroy_line_struct(Points);
    Vect_destroy_cats_struct(Cats);
 
    return List->n_values;
}
 
/*!
   \brief Query selected primitive
 
   \return 1 line test positive
   \return 0 line test negative
   \return -1 on error (line is dead)
 */
int select_by_query(struct Map_info *Map, int line, int type, double thresh,
                    int query, struct line_pnts *Points, struct line_cats *Cats)
{
    int ltype;
    double length;
    int i, cat_curr;
    int node1, node2, node;        /* nodes */
    int nnode1, nnode2;            /* number of line in node */
    double nx, ny, nz;             /* node coordinates */
    struct ilist *exclude, *found; /* line id of nearest lines */
    struct line_cats *Cats_curr;
 
    if (!Vect_line_alive(Map, line))
        return -1;
 
    ltype = Vect_read_line(Map, Points, Cats, line);
 
    if (!(ltype & type))
        return -1;
 
    if (query == QUERY_LENGTH) {
        length = Vect_line_length(Points);
        if (thresh <= 0.0) { /* shorter then */
            if (length <= fabs(thresh))
                return 1;
        }
        else { /* longer then */
            if (length > thresh)
                return 1;
        }
    }
    else if (query == QUERY_DANGLE) {
        /*
           this code is currently replaced by Vect_select_dangle()
           not used by v.edit
         */
        int layer, cat;
 
        layer = 1;
        Vect_cat_get(Cats, layer, &cat); /* get first category from layer */
        if (!(type & GV_LINES))
            return -1;
        /* check if line is dangle */
 
        Vect_get_line_nodes(Map, line, &node1, &node2);
 
        node = -1;
        nnode1 = Vect_get_node_n_lines(Map, node1);
        nnode2 = Vect_get_node_n_lines(Map, node2);
 
        if ((nnode1 == 4 && nnode2 == 1) || (nnode1 == 1 && nnode2 == 4)) {
            if (nnode1 == 4)
                node = node1;
            else
                node = node2;
        }
 
        /* no dangle ? */
        if (node == -1)
            return -1;
 
        length = Vect_line_length(Points);
        if (thresh <= 0.0) { /* shorter then */
            if (length > fabs(thresh))
                return -1;
        }
        else { /* longer then */
            if (length <= thresh)
                return -1;
        }
 
        /* at least one of the lines need to have same category number */
        exclude = Vect_new_list();
        found = Vect_new_list();
 
        Vect_get_node_coor(Map, node, &nx, &ny, &nz);
 
        Vect_list_append(exclude, line);
        Vect_find_line_list(Map, nx, ny, nz, GV_LINES, 0.0, WITHOUT_Z, exclude,
                            found);
 
        Cats_curr = Vect_new_cats_struct();
 
        for (i = 0; i < found->n_values; i++) {
            Vect_read_line(Map, NULL, Cats_curr, found->value[i]);
            if (Vect_cat_get(Cats_curr, layer, &cat_curr) > -1) {
                if (cat == cat_curr)
                    return 1;
            }
        }
 
        Vect_destroy_cats_struct(Cats_curr);
        Vect_destroy_list(exclude);
        Vect_destroy_list(found);
    }
    else {
        /* this shouldn't happen */
        G_fatal_error("Vedit_select_by_query(): %s", _("Unknown query tool"));
    }
 
    return 0;
}
 
/*!
   \brief Merge two lists, i.e. store only duplicate items
 
   \param[in,out] alist list to be merged
   \param blist list used for merging
 
   \return result number of items
 */
int merge_lists(struct ilist *alist, struct ilist *blist)
{
    int i;
 
    struct ilist *list_del;
 
    list_del = Vect_new_list();
 
    for (i = 0; i < alist->n_values; i++) {
        if (!Vect_val_in_list(blist, alist->value[i]))
            Vect_list_append(list_del, alist->value[i]);
    }
 
    Vect_list_delete_list(alist, list_del);
 
    Vect_destroy_list(list_del);
 
    return alist->n_values;
}