gojs/extensionsJSM/OverviewResizingTool.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';

/**
 * The OverviewResizingTool class lets the user resize the box within an overview.
 *
 * If you want to experiment with this extension, try the <a href="../../extensionsJSM/OverviewResizing.html">Overview Resizing</a> sample.
 * @category Tool Extension
 */
export class OverviewResizingTool extends go.ResizingTool {
  // Internal property used to keep track of changing handle size
  private _handleSize: go.Size;

  /**
   * Constructs an OverviewResizingTool and sets the name for the tool.
   */
  constructor() {
    super();
    this.name = 'OverviewResizing';
    this._handleSize = new go.Size(6, 6);
  }

  /**
   * @hidden @internal
   * @param {Shape} resizeBox
   * @return {Adornment}
   */
  public makeAdornment(resizeBox: go.Shape): go.Adornment {
    this._handleSize.setTo(resizeBox.strokeWidth * 3, resizeBox.strokeWidth * 3);
    // Set up the resize adornment
    const ad = new go.Adornment();
    ad.type = go.Panel.Spot;
    ad.locationSpot = go.Spot.Center;
    const ph = new go.Placeholder();
    ph.isPanelMain = true;
    ad.add(ph);
    const hnd = new go.Shape();
    hnd.name = 'RSZHND';
    hnd.figure = 'Rectangle';
    hnd.desiredSize = this._handleSize;
    hnd.cursor = 'se-resize';
    hnd.alignment = go.Spot.BottomRight;
    hnd.alignmentFocus = go.Spot.Center;
    ad.add(hnd);
    ad.adornedObject = resizeBox;
    return ad;
  }

  /**
   * @hidden @internal
   * Keep the resize handle properly sized as the scale is changing.
   * This overrides an undocumented method on the ResizingTool.
   * @param {Adornment} elt
   * @param {number} angle
   */
  public updateResizeHandles(elt: go.Adornment, angle: number) {
    if (elt === null) return;
    const handle = elt.findObject('RSZHND') as go.Shape;
    const box = elt.adornedObject as go.Shape;
    this._handleSize.setTo(box.strokeWidth * 3, box.strokeWidth * 3);
    handle.desiredSize = this._handleSize;
  }

  /**
   * Overrides {@link ResizingTool#resize} to resize the overview box via setting the observed diagram's scale.
   * @param {Rect} newr the intended new rectangular bounds the overview box.
   */
  public resize(newr: go.Rect): void {
    const overview = this.diagram as go.Overview;
    const observed = overview.observed;
    if (observed === null) return;
    const oldr = observed.viewportBounds.copy();
    const oldscale = observed.scale;
    if (oldr.width !== newr.width || oldr.height !== newr.height) {
      if (newr.width > 0 && newr.height > 0) {
        observed.scale = Math.min(oldscale * oldr.width / newr.width, oldscale * oldr.height / newr.height);
      }
    }
  }
}