gojs/extensionsJSM/RescalingTool.ts

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

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

// A custom Tool to change the scale of an object in a Part.

/*
* 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.
*/

/**
* A custom tool for rescaling an object.
*
* Install the RescalingTool as a mouse-down tool by calling:
* myDiagram.toolManager.mouseDownTools.add(new RescalingTool());
*
* Normally it would not make sense for the same object to be both resizable and rescalable.
*
* Note that there is no <code>Part.rescaleObjectName</code> property and there is no <code>Part.rescalable</code> property.
* So although you cannot customize any Node to affect this tool, you can set
* <a>RescalingTool.rescaleObjectName</a> and set <a>RescalingTool.isEnabled</a> to control
* whether objects are rescalable and when.
*
* If you want to experiment with this extension, try the <a href="../../extensionsJSM/Rescaling.html">Rescaling</a> sample.
* @category Tool Extension
*/
export class RescalingTool extends go.Tool {
  private _rescaleObjectName: string = "";
  private _handleArchetype: go.GraphObject;

  // internal state
  private _adornedObject: go.GraphObject | null = null;

  private _handle: go.GraphObject | null = null;

  private originalPoint = new go.Point();
  private originalTopLeft = new go.Point();
  private originalScale = 1.0;

  constructor() {
    super();
    this.name = "Rescaling";

    var h = new go.Shape();
    h.desiredSize = new go.Size(8, 8);
    h.fill = "lightblue";
    h.stroke = "dodgerblue";
    h.strokeWidth = 1;
    h.cursor = "nwse-resize";
    this._handleArchetype = h;
  }
  /**
   * Gets the {@link GraphObject} that is being rescaled.
   * This may be the same object as the selected {@link Part} or it may be contained within that Part.
   *
   * This property is also settable, but should only be set when overriding functions
   * in RescalingTool, and not during normal operation.
   */
  get adornedObject(): go.GraphObject | null { return this._adornedObject; }
  set adornedObject(val: go.GraphObject | null) { this._adornedObject = val; }

  /**
   * Gets or sets a small GraphObject that is copied as a rescale handle for the selected part.
   * By default this is a {@link Shape} that is a small blue square.
   * Setting this property does not raise any events.
   *
   * Here is an example of changing the default handle to be green "X":
   * ```js
   *   tool.handleArchetype =
   *     $(go.Shape, "XLine",
   *       { width: 8, height: 8, stroke: "green", fill: "transparent" });
   * ```
   */
  get handleArchetype(): go.GraphObject { return this._handleArchetype; }
  set handleArchetype(val: go.GraphObject ) { this._handleArchetype = val; }

  /**
   * This property returns the {@link GraphObject} that is the tool handle being dragged by the user.
   * This will be contained by an {@link Adornment} whose category is "RescalingTool".
   * Its {@link Adornment#adornedObject} is the same as the {@link #adornedObject}.
   *
   * This property is also settable, but should only be set either within an override of {@link #doActivate}
   * or prior to calling {@link #doActivate}.
   */
  get handle(): go.GraphObject | null { return this._handle; }
  set handle(val: go.GraphObject | null) { this._handle = val; }

  /**
   * This property returns the name of the GraphObject that identifies the object to be rescaled by this tool.
   *
   * The default value is the empty string, resulting in the whole Node being rescaled.
   * This property is used by findRescaleObject when calling {@link Panel#findObject}.
   */
  get rescaleObjectName(): string { return this._rescaleObjectName; }
  set rescaleObjectName(val: string) { this._rescaleObjectName = val; }

  /**
  * @this {RescalingTool}
  * @param {Part} part
  */
  updateAdornments(part: go.Part | null) {
    if (part === null || part instanceof go.Link) return;
    if (part.isSelected && !this.diagram.isReadOnly) {
      var rescaleObj = this.findRescaleObject(part);
      if (rescaleObj !== null && part.actualBounds.isReal() && part.isVisible() &&
          rescaleObj.actualBounds.isReal() && rescaleObj.isVisibleObject()) {
        var adornment = part.findAdornment(this.name);
        if (adornment === null || adornment.adornedObject !== rescaleObj) {
          adornment = this.makeAdornment(rescaleObj);
        }
        if (adornment !== null) {
          adornment.location = rescaleObj.getDocumentPoint(go.Spot.BottomRight);
          part.addAdornment(this.name, adornment);
          return;
        }
      }
    }
    part.removeAdornment(this.name);
  }

  /**
  * @this {RescalingTool}
  * @param {GraphObject} rescaleObj
  * @return {Adornment}
  */
  makeAdornment(rescaleObj: go.GraphObject | null): go.Adornment {
    var adornment = new go.Adornment();
    adornment.type = go.Panel.Position;
    adornment.locationSpot = go.Spot.Center;
    adornment.add(this._handleArchetype.copy());
    adornment.adornedObject = rescaleObj;
    return adornment;
  }

  /**
  * Return the GraphObject to be rescaled by the user.
  * @this {RescalingTool}
  * @return {GraphObject}
  */
  findRescaleObject(part: go.Part): go.GraphObject {
    var obj = part.findObject(this.rescaleObjectName);
    if (obj) return obj;
    return part;
  }

  /**
  * This tool can start running if the mouse-down happens on a "Rescaling" handle.
  * @this {RescalingTool}
  * @return {boolean}
  */
  canStart(): boolean {
    var diagram = this.diagram;
    if (diagram === null || diagram.isReadOnly) return false;
    if (!diagram.lastInput.left) return false;
    var h = this.findToolHandleAt(diagram.firstInput.documentPoint, this.name);
    return (h !== null);
  }

  /**
  * Activating this tool remembers the {@link #handle} that was dragged,
  * the {@link #adornedObject} that is being rescaled,
  * starts a transaction, and captures the mouse.
  * @this {RescalingTool}
  */
  doActivate(): void {
    var diagram = this.diagram;
    if (diagram === null) return;
    this._handle = this.findToolHandleAt(diagram.firstInput.documentPoint, this.name);
    if (this._handle === null) return;
    var ad = this._handle.part;
    this._adornedObject = (ad instanceof go.Adornment) ? ad.adornedObject : null;
    if (!this._adornedObject) return;
    this.originalPoint = this._handle.getDocumentPoint(go.Spot.Center);
    this.originalTopLeft = this._adornedObject.getDocumentPoint(go.Spot.TopLeft);
    this.originalScale = this._adornedObject.scale;
    diagram.isMouseCaptured = true;
    diagram.delaysLayout = true;
    this.startTransaction(this.name);
    this.isActive = true;
  }

  /**
  * Stop the current transaction, forget the {@link #handle} and {@link #adornedObject}, and release the mouse.
  * @this {RescalingTool}
  */
  doDeactivate(): void {
    var diagram = this.diagram;
    if (diagram === null) return;
    this.stopTransaction();
    this._handle = null;
    this._adornedObject = null;
    diagram.isMouseCaptured = false;
    this.isActive = false;
  };

  /**
  * Restore the original {@link GraphObject#scale} of the adorned object.
  * @this {RescalingTool}
  */
  doCancel(): void {
    var diagram = this.diagram;
    if (diagram !== null) diagram.delaysLayout = false;
    this.scale(this.originalScale);
    this.stopTool();
  }

  /**
  * Call {@link #scale} with a new scale determined by the current mouse point.
  * This determines the new scale by calling {@link #computeScale}.
  * @this {RescalingTool}
  */
  doMouseMove(): void {
    var diagram = this.diagram;
    if (this.isActive && diagram !== null) {
      var newScale = this.computeScale(diagram.lastInput.documentPoint);
      this.scale(newScale);
    }
  }

  /**
  * Call {@link #scale} with a new scale determined by the most recent mouse point,
  * and commit the transaction.
  * @this {RescalingTool}
  */
  doMouseUp(): void {
    var diagram = this.diagram;
    if (this.isActive && diagram !== null) {
      diagram.delaysLayout = false;
      var newScale = this.computeScale(diagram.lastInput.documentPoint);
      this.scale(newScale);
      this.transactionResult = this.name;
    }
    this.stopTool();
  }

  /**
  * Set the {@link GraphObject#scale} of the {@link #findRescaleObject}.
  * @this {RescalingTool}
  * @param {number} newScale
  */
  scale(newScale: number): void {
    if (this._adornedObject !== null) {
      this._adornedObject.scale = newScale;
    }
  }

  /**
  * Compute the new scale given a point.
  *
  * This method is called by both {@link #doMouseMove} and {@link #doMouseUp}.
  * This method may be overridden.
  * Please read the Introduction page on <a href="../../intro/extensions.html">Extensions</a> for how to override methods and how to call this base method.
  * @this {RescalingTool}
  * @param {Point} newPoint in document coordinates
  */
  computeScale(newPoint: go.Point): number {
    var scale = this.originalScale;
    var origdist = Math.sqrt(this.originalPoint.distanceSquaredPoint(this.originalTopLeft));
    var newdist = Math.sqrt(newPoint.distanceSquaredPoint(this.originalTopLeft));
    return scale * (newdist/origdist);
  }
}