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
  \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, 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;
}