lwcompound.c

Go to the documentation of this file.

/**********************************************************************
 *
 * PostGIS - Spatial Types for PostgreSQL
 * http://postgis.net
 *
 * PostGIS is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * PostGIS is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with PostGIS.  If not, see <http://www.gnu.org/licenses/>.
 *
 **********************************************************************
 *
 * Copyright (C) 2001-2006 Refractions Research Inc.
 *
 **********************************************************************/
 
 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "liblwgeom_internal.h"
#include "lwgeom_log.h"
 
 
 
int
lwcompound_is_closed(const LWCOMPOUND *compound)
{
        size_t size;
        int npoints=0;
 
        if ( lwgeom_has_z((LWGEOM*)compound) )
        {
                size = sizeof(POINT3D);
        }
        else
        {
                size = sizeof(POINT2D);
        }
 
        if ( compound->geoms[compound->ngeoms - 1]->type == CIRCSTRINGTYPE )
        {
                npoints = ((LWCIRCSTRING *)compound->geoms[compound->ngeoms - 1])->points->npoints;
        }
        else if (compound->geoms[compound->ngeoms - 1]->type == LINETYPE)
        {
                npoints = ((LWLINE *)compound->geoms[compound->ngeoms - 1])->points->npoints;
        }
 
        if ( memcmp(getPoint_internal( (POINTARRAY *)compound->geoms[0]->data, 0),
                    getPoint_internal( (POINTARRAY *)compound->geoms[compound->ngeoms - 1]->data,
                                       npoints - 1),
                    size) )
        {
                return LW_FALSE;
        }
 
        return LW_TRUE;
}
 
double lwcompound_length(const LWCOMPOUND *comp)
{
        return lwcompound_length_2d(comp);
}
 
double lwcompound_length_2d(const LWCOMPOUND *comp)
{
        uint32_t i;
        double length = 0.0;
        if ( lwgeom_is_empty((LWGEOM*)comp) )
                return 0.0;
 
        for (i = 0; i < comp->ngeoms; i++)
        {
                length += lwgeom_length_2d(comp->geoms[i]);
        }
        return length;
}
 
int lwcompound_add_lwgeom(LWCOMPOUND *comp, LWGEOM *geom)
{
        LWCOLLECTION *col = (LWCOLLECTION*)comp;
 
        /* Empty things can't continuously join up with other things */
        if ( lwgeom_is_empty(geom) )
        {
                LWDEBUG(4, "Got an empty component for a compound curve!");
                return LW_FAILURE;
        }
 
        if( col->ngeoms > 0 )
        {
                POINT4D last, first;
                /* First point of the component we are adding */
                LWLINE *newline = (LWLINE*)geom;
                /* Last point of the previous component */
                LWLINE *prevline = (LWLINE*)(col->geoms[col->ngeoms-1]);
 
                getPoint4d_p(newline->points, 0, &first);
                getPoint4d_p(prevline->points, prevline->points->npoints-1, &last);
 
                if ( !(FP_EQUALS(first.x,last.x) && FP_EQUALS(first.y,last.y)) )
                {
                        LWDEBUG(4, "Components don't join up end-to-end!");
                        LWDEBUGF(4, "first pt (%g %g %g %g) last pt (%g %g %g %g)", first.x, first.y, first.z, first.m, last.x, last.y, last.z, last.m);
                        return LW_FAILURE;
                }
        }
 
        col = lwcollection_add_lwgeom(col, geom);
        return LW_SUCCESS;
}
 
LWCOMPOUND *
lwcompound_construct_empty(int32_t srid, char hasz, char hasm)
{
        LWCOMPOUND *ret = (LWCOMPOUND*)lwcollection_construct_empty(COMPOUNDTYPE, srid, hasz, hasm);
        return ret;
}
 
int lwgeom_contains_point(const LWGEOM *geom, const POINT2D *pt)
{
        switch( geom->type )
        {
                case LINETYPE:
                        return ptarray_contains_point(((LWLINE*)geom)->points, pt);
                case CIRCSTRINGTYPE:
                        return ptarrayarc_contains_point(((LWCIRCSTRING*)geom)->points, pt);
                case COMPOUNDTYPE:
                        return lwcompound_contains_point((LWCOMPOUND*)geom, pt);
        }
        lwerror("lwgeom_contains_point failed");
        return LW_FAILURE;
}
 
 
/*
 * Use a ray-casting count to determine if the point
 * is inside or outside of the compound curve. Ray-casting
 * is run against each component of the overall arc, and
 * the even/odd test run against the total of all components.
 * Returns LW_INSIDE / LW_BOUNDARY / LW_OUTSIDE
 */
int
lwcompound_contains_point(const LWCOMPOUND *comp, const POINT2D *pt)
{
        int intersections = 0;
 
        if (lwgeom_is_empty(lwcompound_as_lwgeom(comp)))
                return LW_OUTSIDE;
 
        for (uint32_t j = 0; j < comp->ngeoms; j++)
        {
                int on_boundary = LW_FALSE;
                const LWGEOM *sub = comp->geoms[j];
                if (sub->type == LINETYPE)
                {
                        LWLINE *lwline = lwgeom_as_lwline(sub);
                        intersections += ptarray_raycast_intersections(lwline->points, pt, &on_boundary);
                }
                else if (sub->type == CIRCSTRINGTYPE)
                {
                        LWCIRCSTRING *lwcirc = lwgeom_as_lwcircstring(sub);
                        intersections += ptarrayarc_raycast_intersections(lwcirc->points, pt, &on_boundary);
                }
                else
                {
                        lwerror("%s: unsupported type %s", __func__, lwtype_name(sub->type));
                }
                if (on_boundary)
                        return LW_BOUNDARY;
        }
 
        /*
         * Odd number of intersections means inside.
         * Even means outside.
         */
        return (intersections % 2) ? LW_INSIDE : LW_OUTSIDE;
}
 
LWCOMPOUND *
lwcompound_construct_from_lwline(const LWLINE *lwline)
{
  LWCOMPOUND* ogeom = lwcompound_construct_empty(lwline->srid, FLAGS_GET_Z(lwline->flags), FLAGS_GET_M(lwline->flags));
  lwcompound_add_lwgeom(ogeom, lwgeom_clone((LWGEOM*)lwline));
        /* ogeom->bbox = lwline->bbox; */
  return ogeom;
}
 
LWPOINT*
lwcompound_get_lwpoint(const LWCOMPOUND *lwcmp, uint32_t where)
{
        uint32_t i;
        uint32_t count = 0;
        uint32_t npoints = 0;
        if ( lwgeom_is_empty((LWGEOM*)lwcmp) )
                return NULL;
 
        npoints = lwgeom_count_vertices((LWGEOM*)lwcmp);
        if ( where >= npoints )
        {
                lwerror("%s: index %d is not in range of number of vertices (%d) in input", __func__, where, npoints);
                return NULL;
        }
 
        for ( i = 0; i < lwcmp->ngeoms; i++ )
        {
                LWGEOM* part = lwcmp->geoms[i];
                uint32_t npoints_part = lwgeom_count_vertices(part);
                if ( where >= count && where < count + npoints_part )
                {
                        return lwline_get_lwpoint((LWLINE*)part, where - count);
                }
                else
                {
                        count += npoints_part;
                }
        }
 
        return NULL;
}
 
 
 
LWPOINT *
lwcompound_get_startpoint(const LWCOMPOUND *lwcmp)
{
        return lwcompound_get_lwpoint(lwcmp, 0);
}
 
LWPOINT *
lwcompound_get_endpoint(const LWCOMPOUND *lwcmp)
{
        LWLINE *lwline;
        if ( lwcmp->ngeoms < 1 )
        {
                return NULL;
        }
 
        lwline = (LWLINE*)(lwcmp->geoms[lwcmp->ngeoms-1]);
 
        if ( (!lwline) || (!lwline->points) || (lwline->points->npoints < 1) )
        {
                return NULL;
        }
 
        return lwline_get_lwpoint(lwline, lwline->points->npoints-1);
}