lwgeom_wrapx()

LWGEOM * lwgeom_wrapx	(	const LWGEOM *	lwgeom_in,
		double	cutx,
		double	amount
	)

wrap geometry on given cut x value

For a positive amount, shifts anything that is on the left of "cutx" to the right by the given amount.

For a negative amount, shifts anything that is on the right of "cutx" to the left by the given absolute amount.

Parameters

cutx	the X value to perform wrapping on
amount	shift amount and wrapping direction

Definition at line 169 of file lwgeom_wrapx.c.

{
        /* Nothing to wrap in an empty geom */
        if ( lwgeom_is_empty(lwgeom_in) )
        {
                LWDEBUG(2, "geom is empty, cloning");
                return lwgeom_clone_deep(lwgeom_in);
        }
 
        /* Nothing to wrap if shift amount is zero */
        if ( amount == 0 )
        {
                LWDEBUG(2, "amount is zero, cloning");
                return lwgeom_clone_deep(lwgeom_in);
        }
 
        switch (lwgeom_in->type)
        {
        case LINETYPE:
        case POLYGONTYPE:
                LWDEBUG(2, "split-wrapping line or polygon");
                return lwgeom_split_wrapx(lwgeom_in, cutx, amount);
 
        case POINTTYPE:
        {
                const LWPOINT *pt = lwgeom_as_lwpoint(lwgeom_clone_deep(lwgeom_in));
                POINT4D pt4d;
                getPoint4d_p(pt->point, 0, &pt4d);
 
                LWDEBUGF(2, "POINT X is %g, cutx:%g, amount:%g", pt4d.x, cutx, amount);
 
                if ( ( amount < 0 && pt4d.x > cutx ) || ( amount > 0 && pt4d.x < cutx ) )
                {
                        pt4d.x += amount;
                        ptarray_set_point4d(pt->point, 0, &pt4d);
                }
                return lwpoint_as_lwgeom(pt);
        }
 
        case MULTIPOINTTYPE:
        case MULTIPOLYGONTYPE:
        case MULTILINETYPE:
        case COLLECTIONTYPE:
                LWDEBUG(2, "collection-wrapping multi");
                return lwcollection_as_lwgeom(
                                                lwcollection_wrapx((const LWCOLLECTION*)lwgeom_in, cutx, amount)
                                         );
 
        default:
                lwerror("Wrapping of %s geometries is unsupported",
                        lwtype_name(lwgeom_in->type));
                return NULL;
        }
 
}

References COLLECTIONTYPE, getPoint4d_p(), LINETYPE, lwcollection_as_lwgeom(), lwcollection_wrapx(), LWDEBUG, LWDEBUGF, lwerror(), lwgeom_as_lwpoint(), lwgeom_clone_deep(), lwgeom_is_empty(), lwgeom_split_wrapx(), lwpoint_as_lwgeom(), lwtype_name(), MULTILINETYPE, MULTIPOINTTYPE, MULTIPOLYGONTYPE, LWPOINT::point, POINTTYPE, POLYGONTYPE, ptarray_set_point4d(), LWGEOM::type, LWCOLLECTION::type, and POINT4D::x.

Referenced by lwcollection_wrapx(), ST_WrapX(), and test_lwgeom_wrapx().

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