rect_tree_area_contains_point()

static int rect_tree_area_contains_point ( RECT_NODE *  node, const POINT2D *  pt  )

static

Definition at line 344 of file lwtree.c.

{
        /* Can't do anything with a leaf node, makes no sense */
        if (rect_node_is_leaf(node))
                return 0;
 
        /* Iterate into area until we find ring heads */
        if (node->i.ring_type == RECT_NODE_RING_NONE)
        {
                int i, sum = 0;
                for (i = 0; i < node->i.num_nodes; i++)
                        sum += rect_tree_area_contains_point(node->i.nodes[i], pt);
                return sum;
        }
        /* See if the ring encloses the point */
        else
        {
                int on_boundary = 0;
                int edge_crossing_count = rect_tree_ring_contains_point(node, pt, &on_boundary);
                /* Odd number of crossings => contained */
                int contained = (edge_crossing_count % 2 == 1);
                /* External rings return positive containment, interior ones negative, */
                /* so that a point-in-hole case nets out to zero (contained by both */
                /* interior and exterior rings. */
                if (node->i.ring_type == RECT_NODE_RING_INTERIOR)
                {
                        return on_boundary ? 0 : -1 * contained;
                }
                else
                {
                        return contained || on_boundary;
                }
 
        }
}

References rect_node::i, RECT_NODE_INTERNAL::nodes, RECT_NODE_INTERNAL::num_nodes, rect_node_is_leaf(), RECT_NODE_RING_INTERIOR, RECT_NODE_RING_NONE, rect_tree_ring_contains_point(), and RECT_NODE_INTERNAL::ring_type.

Referenced by rect_tree_contains_point().

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