lwtriangle_clip_to_ordinate_range()

static LWCOLLECTION* lwtriangle_clip_to_ordinate_range ( const LWTRIANGLE *  tri, char  ordinate, double  from, double  to  )

inlinestatic

Clip an input LWTRIANGLE between two values, on any ordinate input.

Definition at line 751 of file lwlinearreferencing.c.

{
        assert(tri);
        char hasz = FLAGS_GET_Z(tri->flags), hasm = FLAGS_GET_M(tri->flags);
        LWCOLLECTION *lwgeom_out = lwcollection_construct_empty(TINTYPE, tri->srid, hasz, hasm);
        POINTARRAY *pa = ptarray_clamp_to_ordinate_range(tri->points, ordinate, from, to, LW_TRUE);
 
        if (!pa)
                return NULL;
 
        if (pa->npoints >= 4)
        {
                POINT4D first = getPoint4d(pa, 0);
                for (uint32_t i = 1; i < pa->npoints - 2; i++)
                {
                        POINT4D p;
                        POINTARRAY *tpa = ptarray_construct_empty(hasz, hasm, 4);
                        ptarray_append_point(tpa, &first, LW_TRUE);
                        getPoint4d_p(pa, i, &p);
                        ptarray_append_point(tpa, &p, LW_TRUE);
                        getPoint4d_p(pa, i + 1, &p);
                        ptarray_append_point(tpa, &p, LW_TRUE);
                        ptarray_append_point(tpa, &first, LW_TRUE);
                        LWTRIANGLE *otri = lwtriangle_construct(tri->srid, NULL, tpa);
                        lwgeom_out = lwcollection_add_lwgeom(lwgeom_out, (LWGEOM *)otri);
                }
        }
        ptarray_free(pa);
        return lwgeom_out;
}

References LWTRIANGLE::flags, FLAGS_GET_M, FLAGS_GET_Z, getPoint4d(), getPoint4d_p(), LW_TRUE, lwcollection_add_lwgeom(), lwcollection_construct_empty(), lwtriangle_construct(), POINTARRAY::npoints, LWTRIANGLE::points, ptarray_append_point(), ptarray_clamp_to_ordinate_range(), ptarray_construct_empty(), ptarray_free(), LWTRIANGLE::srid, and TINTYPE.

Referenced by lwgeom_clip_to_ordinate_range().

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