gojs/extensionsJSM/TreeMapLayout.ts

/*
*  Copyright (C) 1998-2021 by Northwoods Software Corporation. All Rights Reserved.
*/

/*
* This is an extension and not part of the main GoJS library.
* Note that the API for this class may change with any version, even point releases.
* If you intend to use an extension in production, you should copy the code to your own source directory.
* Extensions can be found in the GoJS kit under the extensions or extensionsTS folders.
* See the Extensions intro page (https://gojs.net/latest/intro/extensions.html) for more information.
*/

import * as go from '../release/go-module.js';

/**
 * A custom {@link Layout} that lays out hierarchical data using nested rectangles.
 *
 * If you want to experiment with this extension, try the <a href="../../extensionsJSM/TreeMap.html">Tree Map Layout</a> sample.
 * @category Layout Extension
 */
export class TreeMapLayout extends go.Layout {
  private _isTopLevelHorizontal: boolean = false;

  /**
   * Gets or sets whether top level Parts are laid out horizontally.
   */
  get isTopLevelHorizontal(): boolean { return this._isTopLevelHorizontal; }
  set isTopLevelHorizontal(val: boolean) {
    if (this._isTopLevelHorizontal !== val) {
      this._isTopLevelHorizontal = val;
      this.invalidateLayout();
    }
  }

  /**
   * Copies properties to a cloned Layout.
   */
  public cloneProtected(copy: this): void {
    super.cloneProtected(copy);
    copy._isTopLevelHorizontal = this._isTopLevelHorizontal;
  }

  /**
   * This method actually positions all of the nodes by determining total area and then recursively tiling nodes from the top-level down.
   * @param {Diagram|Group|Iterable.<Part>} coll A {@link Diagram} or a {@link Group} or a collection of {@link Part}s.
   */
  public doLayout(coll: go.Diagram | go.Group | go.Iterable<go.Part>): void {
    if (!(coll instanceof go.Diagram)) throw new Error('TreeMapLayout only works as the Diagram.layout');
    const diagram = coll;
    this.computeTotals(diagram);  // make sure data.total has been computed for every node
    // figure out how large an area to cover;
    // perhaps this should be a property that could be set, rather than depending on the current viewport
    this.arrangementOrigin = this.initialOrigin(this.arrangementOrigin);
    const x = this.arrangementOrigin.x;
    const y = this.arrangementOrigin.y;
    let w = diagram.viewportBounds.width;
    let h = diagram.viewportBounds.height;
    if (isNaN(w)) w = 1000;
    if (isNaN(h)) h = 1000;
    // collect all top-level nodes, and sum their totals
    const tops = new go.Set<go.Node>();
    let total = 0;
    diagram.nodes.each((n) => {
      if (n.isTopLevel) {
        tops.add(n);
        total += n.data.total;
      }
    });
    const horiz = this.isTopLevelHorizontal;  // initially horizontal layout?
    // the following was copied from the layoutNode method
    let gx = x;
    let gy = y;
    const lay = this;
    tops.each((n: go.Node) => {
      const tot = n.data.total;
      if (horiz) {
        const pw = w * tot / total;
        lay.layoutNode(!horiz, n, gx, gy, pw, h);
        gx += pw;
      } else {
        const ph = h * tot / total;
        lay.layoutNode(!horiz, n, gx, gy, w, ph);
        gy += ph;
      }
    });
  }

  /**
   * @hidden @internal
   */
  public layoutNode(horiz: boolean, n: go.Panel, x: number, y: number, w: number, h: number): void {
    n.position = new go.Point(x, y);
    n.desiredSize = new go.Size(w, h);
    if (n instanceof go.Group) {
      const g = n;
      const total = g.data.total;
      let gx = x;
      let gy = y;
      const lay = this;
      g.memberParts.each((p) => {
        if (p instanceof go.Link) return;
        const tot = p.data.total;
        if (horiz) {
          const pw = w * tot / total;
          lay.layoutNode(!horiz, p, gx, gy, pw, h);
          gx += pw;
        } else {
          const ph = h * tot / total;
          lay.layoutNode(!horiz, p, gx, gy, w, ph);
          gy += ph;
        }
      });
    }
  }

  /**
   * Compute the `data.total` for each node in the Diagram, with a {@link Group}'s being a sum of its members.
   */
  public computeTotals(diagram: go.Diagram): void {
    if (!diagram.nodes.all((g: go.Node) => !(g instanceof go.Group) || g.data.total >= 0)) {
      let groups = new go.Set<go.Group>();
      diagram.nodes.each((n: go.Node) => {
        if (n instanceof go.Group) {  // collect all groups
          groups.add(n);
        } else {  // regular nodes just have their total == size
          n.data.total = n.data.size;
        }
      });
      // keep looking for groups whose total can be computed, until all groups have been processed
      while (groups.count > 0) {
        const grps = new go.Set<go.Group>();
        groups.each((g: go.Group) => {
          // for a group all of whose member nodes have an initialized data.total,
          if (g.memberParts.all((m) => !(m instanceof go.Group) || m.data.total >= 0)) {
            // compute the group's total as the sum of the sizes of all of the member nodes
            g.data.total = 0;
            g.memberParts.each((m) => { if (m instanceof go.Node) g.data.total += m.data.total; });
          } else {  // remember for the next iteration
            grps.add(g);
          }
        });
        groups = grps;
      }
    }
  }

}