create-gojs-kit/dist/extensionsJSM/ResizeMultipleTool.ts

A CLI for downloading GoJS samples, extensions, and docs

/*
 *  Copyright 1998-2025 by Northwoods Software Corporation. All Rights Reserved.
 */

/*
 * This is an extension and not part of the main GoJS library.
 * The source code for this is at extensionsJSM/ResizeMultipleTool.ts.
 * 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 extensionsJSM folders.
 * See the Extensions intro page (https://gojs.net/latest/intro/extensions.html) for more information.
 */

import * as go from 'gojs';

/**
 * The ResizeMultipleTool class lets the user resize multiple objects at once.
 *
 * If you want to experiment with this extension, try the <a href="../../samples/ResizeMultiple.html">Resize Multiple</a> sample.
 * @category Tool Extension
 */
export class ResizeMultipleTool extends go.ResizingTool {
  /**
   * Constructs a ResizeMultipleTool and sets the name for the tool.
   */
  constructor(init?: Partial<ResizeMultipleTool>) {
    super();
    this.name = 'ResizeMultiple';
    if (init) Object.assign(this, init);
  }

  /**
   * Overrides {@link go.ResizingTool.resize} to resize all selected objects to the same size.
   * @param newr - the intended new rectangular bounds for each Part's {@link go.Part.resizeObject}.
   */
  override resize(newr: go.Rect): void {
    const diagram = this.diagram;
    diagram.selection.each((part) => {
      if (part instanceof go.Link) return; // only Nodes and simple Parts
      const obj = part.resizeObject;

      // calculate new location
      const pos = part.position.copy();
      const angle = obj.getDocumentAngle();
      const sc = obj.getDocumentScale();

      const radAngle = (Math.PI * angle) / 180;
      const angleCos = Math.cos(radAngle);
      const angleSin = Math.sin(radAngle);

      const deltaWidth = newr.width - obj.naturalBounds.width;
      const deltaHeight = newr.height - obj.naturalBounds.height;

      const angleBottom = angle > 0 && angle < 180 ? 1 : 0;
      const angleLeft = angle > 90 && angle < 270 ? 1 : 0;
      const angleTop = angle > 180 && angle < 360 ? 1 : 0;

      pos.x +=
        sc *
        ((newr.x + deltaWidth * angleLeft) * angleCos -
          (newr.y + deltaHeight * angleBottom) * angleSin);
      pos.y +=
        sc *
        ((newr.x + deltaWidth * angleTop) * angleSin +
          (newr.y + deltaHeight * angleLeft) * angleCos);

      obj.desiredSize = newr.size;
      part.move(pos);
    });
  }
}