Function snap_graph_node

generative/snap.rs:256–300

Snap the given node to the closest other node within the given tolerance Returns the NodeIndex that was snapped to, if the given node was snapped.

(
    graph: &mut GeometryGraph<D>,
    node_idx: NodeIndex<usize>,
    index: &mut GraphKdTree,
    tolerance: f64,
)

///
/// Returns the NodeIndex that was snapped to, if the given node was snapped.
fn snap_graph_node<D>(
    graph: &mut GeometryGraph<D>,
    node_idx: NodeIndex<usize>,
    index: &mut GraphKdTree,
    tolerance: f64,
) -> Option<NodeIndex<usize>>
where
    D: EdgeType,
{
    let coords = [graph[node_idx].0.x, graph[node_idx].0.y];
    let nearest_coords = index
        .within(&coords, tolerance, &squared_euclidean)
        .unwrap();

    // There's no node close enough to snap to
    if nearest_coords.is_empty() {
        return None;
    }

    // Find the closest node that isn't the query node itself
    let mut snap_to = None;
    for (_distance, found_idx) in nearest_coords {
        if *found_idx != node_idx {
            snap_to = Some(*found_idx);
            break;
        }
    }

    // We found a node to snap to
    if let Some(found_idx) = snap_to {
        // Remove the snapped from node from the index, but we have to be careful to only remove it
        // if we know the coordinates are actually in the index (duplicate coordinates are filtered
        // out ahead of time because they would otherwise cause infinite loops here)
        if graph[found_idx] != graph[node_idx] {
            // Remove the node we're snapping from
            index.remove(&coords, &node_idx).unwrap();
        }

        // Snap the two nodes together, updating the adjacencies
        snap_graph_nodes(graph, node_idx, found_idx);
        Some(found_idx)
    } else {
        None
    }
}

/// Snap `snap_from` to `snap_to`, and update all of `snap_from`s adjacencies
fn snap_graph_nodes<D>(