lwgeom_clip_by_rect()

LWGEOM* lwgeom_clip_by_rect	(	const LWGEOM *	geom1,
		double	x0,
		double	y0,
		double	x1,
		double	y1
	)

Definition at line 1074 of file liblwgeom/lwgeom_geos.c.

References LWGEOM::flags, FLAGS_GET_Z, GEOS2LWGEOM(), LWDEBUG, LWDEBUGF, lwerror(), LWGEOM2GEOS(), lwgeom_clone_deep(), lwgeom_geos_errmsg, lwgeom_geos_error(), lwgeom_is_empty(), lwnotice(), POSTGIS_GEOS_VERSION, and LWGEOM::srid.

Referenced by lwgeom_subdivide_recursive(), mvt_geom(), ST_ClipByBox2d(), and test_lwgeom_clip_by_rect().

{
#if POSTGIS_GEOS_VERSION < 35
        lwerror("The GEOS version this postgis binary "
                "was compiled against (%d) doesn't support "
                "'GEOSClipByRect' function (3.5.0+ required)",
                POSTGIS_GEOS_VERSION);
        return NULL;
#else /* POSTGIS_GEOS_VERSION >= 35 */
        LWGEOM *result ;
        GEOSGeometry *g1, *g3 ;
        int is3d ;

        /* A.Intersection(Empty) == Empty */
        if ( lwgeom_is_empty(geom1) )
                return lwgeom_clone_deep(geom1);

        is3d = FLAGS_GET_Z(geom1->flags);

        initGEOS(lwnotice, lwgeom_geos_error);

        LWDEBUG(3, "clip_by_rect() START");

        g1 = LWGEOM2GEOS(geom1, 1); /* auto-fix structure */
        if ( 0 == g1 )   /* exception thrown at construction */
        {
                lwerror("First argument geometry could not be converted to GEOS: %s", lwgeom_geos_errmsg);
                return NULL ;
        }

        LWDEBUG(3, " constructed geometrys - calling geos");
        LWDEBUGF(3, " g1 = %s", GEOSGeomToWKT(g1));
        /*LWDEBUGF(3, "g1 is valid = %i",GEOSisvalid(g1)); */

        g3 = GEOSClipByRect(g1,x0,y0,x1,y1);
        GEOSGeom_destroy(g1);

        LWDEBUG(3, " clip_by_rect finished");

        if (g3 == NULL)
        {
                lwnotice("Error performing rectangular clipping: %s", lwgeom_geos_errmsg);
                return NULL;
        }

        LWDEBUGF(3, "result: %s", GEOSGeomToWKT(g3) ) ;

        result = GEOS2LWGEOM(g3, is3d);
        GEOSGeom_destroy(g3);

        if (result == NULL)
        {
                lwerror("Error performing intersection: GEOS2LWGEOM: %s", lwgeom_geos_errmsg);
                return NULL ; /* never get here */
        }

        result->srid = geom1->srid;

        return result ;
#endif /* POSTGIS_GEOS_VERSION >= 35 */
}

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