lwpoly_simplify()

LWPOLY* lwpoly_simplify	(	const LWPOLY *	ipoly,
		double	dist,
		int	preserve_collapsed
	)

Definition at line 464 of file lwpoly.c.

References LWPOLY::flags, FLAGS_GET_M, FLAGS_GET_Z, LW_FAILURE, LWDEBUGF, lwpoly_add_ring(), lwpoly_construct_empty(), lwpoly_free(), lwpoly_is_empty(), POINTARRAY::npoints, LWPOLY::nrings, ovdump::opts, ptarray_free(), ptarray_simplify(), LWPOLY::rings, LWPOLY::srid, and LWPOLY::type.

Referenced by lwgeom_simplify().

{
        int i;
        LWPOLY *opoly = lwpoly_construct_empty(ipoly->srid, FLAGS_GET_Z(ipoly->flags), FLAGS_GET_M(ipoly->flags));

        LWDEBUGF(2, "%s: simplifying polygon with %d rings", __func__, ipoly->nrings);

        if ( lwpoly_is_empty(ipoly) )
        {
                lwpoly_free(opoly);
                return NULL;
        }

        for ( i = 0; i < ipoly->nrings; i++ )
        {
                POINTARRAY *opts;
                int minvertices = 0;

                /* We'll still let holes collapse, but if we're preserving */
                /* and this is a shell, we ensure it is kept */
                if ( preserve_collapsed && i == 0 )
                        minvertices = 4;

                opts = ptarray_simplify(ipoly->rings[i], dist, minvertices);

                LWDEBUGF(3, "ring%d simplified from %d to %d points", i, ipoly->rings[i]->npoints, opts->npoints);

                /* Less points than are needed to form a closed ring, we can't use this */
                if ( opts->npoints < 4 )
                {
                        LWDEBUGF(3, "ring%d skipped (% pts)", i, opts->npoints);
                        ptarray_free(opts);
                        if ( i ) continue;
                        else break; /* Don't scan holes if shell is collapsed */
                }

                /* Add ring to simplified polygon */
                if( lwpoly_add_ring(opoly, opts) == LW_FAILURE )
                {
                        lwpoly_free(opoly);
                        return NULL;
                }
        }

        LWDEBUGF(3, "simplified polygon with %d rings", ipoly->nrings);
        opoly->type = ipoly->type;

        if( lwpoly_is_empty(opoly) )
        {
                lwpoly_free(opoly);
                return NULL;
        }

        return opoly;
}

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