d3-dag
Version:
Layout algorithms for visualizing directed acylic graphs.
62 lines (61 loc) • 2.35 kB
TypeScript
/**
* {@link Coord}s assign `x` coordinates to every node, while
* respecting the {@link SugiSeparation}.
*
* @packageDocumentation
*/
import { SugiNode, SugiSeparation } from "../sugify";
/**
* an operator that assigns coordinates to layered {@link SugiNode}s
*
* This function must assign each node an `x` coordinate, and return the width
* of the layout. The `x` coordinates should satisfy the
* {@link SugiSeparation}, and all be between zero and the returned width.
*
* @example
*
* In order to illustrate what it might look like, below we demonstrate a
* coordinate operator that assigns an x attached to the nodes themselves. If
* the node is a dummy node (e.g. a point on an edge between two nodes), then
* instead we average the coordinate. Note that this isn't compliant since it
* might not respect `sep`, and is therefore only an illustration.
*
* ```ts
* customCoord<N extends { x: number }, L>(layers: SugiNode<N, L>[][], sep: SugiSeparation<N, L>): number {
* // determine span of xs
* let min = Infinity;
* let max = -Infinity;
* for (const layer of layers) {
* for (const node of layer) {
* const { data } = node;
* const x = node.x = data.role === "node" ? data.node.data.x : (data.link.source.data.x + data.link.target.data.x) / 2;
* min = Math.min(min, x - sep(undefined, node));
* max = Math.max(max, x + sep(node, undefined));
* }
* }
* // assign xs
* for (const node of dag) {
* node.x = -= min;
* }
* return max - min;
* }
* ```
*/
export interface Coord<in NodeDatum = never, in LinkDatum = never> {
/**
* assign coordinates to a layered graph
*
* @param layers - a layered graph of sugiyama nodes
* @param sep - how much horizontal separation should exist between nodes
* @returns width - the total width of the layout
*/
<N extends NodeDatum, L extends LinkDatum>(layers: SugiNode<N, L>[][], sep: SugiSeparation<N, L>): number;
/**
* This sentinel field is so that typescript can infer the types of NodeDatum
* and LinkDatum, because the extra generics make it otherwise hard to infer.
* It's a function to keep the same variance.
*
* @internal
*/
__sentinel__?: (_: NodeDatum, __: LinkDatum) => void;
}