d3-sankey-diagram/src/assignRanks/index.js

Sankey diagram d3 plugin

import groupedGraph from './grouped-graph.js'
import makeAcyclic from './make-acyclic.js'
import assignInitialRanks from './initial-ranks.js'
import { min } from 'd3-array'

/**
 * Assign ranks to the nodes in G, according to rankSets.
 */
export default function assignRanks (G, rankSets) {
  // Group nodes together, and add additional edges from Smin to sources
  const GG = groupedGraph(G, rankSets)
  if (GG.nodeCount() === 0) return

  // Add additional edges from Smin to sources
  addTemporaryEdges(GG)

  // Make the graph acyclic
  makeAcyclic(GG, '0')

  // Assign the initial ranks
  assignInitialRanks(GG)

  // XXX improve initial ranking...
  moveSourcesRight(GG)

  // Apply calculated ranks to original graph
  // const ranks = []
  GG.nodes().forEach(u => {
    const groupedNode = GG.node(u)
    // while (node.rank >= ranks.length) ranks.push([])
    groupedNode.nodes.forEach(v => {
      G.node(v).rank = groupedNode.rank
    })
  })
  // return ranks
}

// export function nodeBackwards (link) {
//   if (link.source.direction === 'l') {
//     return link.target.direction === 'l' ? 1 : 0
//   } else {
//     return link.target.direction === 'l' ? 0 : 1
//   }
// }

function addTemporaryEdges (GG) {
  // Add temporary edges between Smin and sources
  GG.sources().forEach(u => {
    if (u !== '0') {
      GG.setEdge('0', u, { temp: true, delta: 0 })
    }
  })

  // XXX Should also add edges from sinks to Smax

  // G.nodes().forEach(u => {
  //   if (!nodeSets.has(u)) {
  //     GG.
  //   }
  // });
}

function moveSourcesRight (GG) {
  GG.edges().forEach(e => {
    const edge = GG.edge(e)
    if (edge.temp) moveRight(e.w)
  })

  function moveRight (v) {
    const V = GG.node(v)
    const rank = min(GG.outEdges(v), e => GG.node(e.w).rank - GG.edge(e).delta)
    if (rank !== undefined) V.rank = rank
  }
}