gojs/extensionsJSM/PolygonDrawingTool.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 PolygonDrawingTool class lets the user draw a new polygon or polyline shape by clicking where the corners should go.
 * Right click or type ENTER to finish the operation.
 *
 * Set {@link #isPolygon} to false if you want this tool to draw open unfilled polyline shapes.
 * Set {@link #archetypePartData} to customize the node data object that is added to the model.
 * Data-bind to those properties in your node template to customize the appearance and behavior of the part.
 *
 * This tool uses a temporary {@link Shape}, {@link #temporaryShape}, held by a {@link Part} in the "Tool" layer,
 * to show interactively what the user is drawing.
 *
 * If you want to experiment with this extension, try the <a href="../../extensionsJSM/PolygonDrawing.html">Polygon Drawing</a> sample.
 * @category Tool Extension
 */
export class PolygonDrawingTool extends go.Tool {
  private _isPolygon: boolean = true;
  private _hasArcs: boolean = false;
  private _isOrthoOnly: boolean = false;
  private _isGridSnapEnabled: boolean = false;
  private _archetypePartData: go.ObjectData= {}; // the data to copy for a new polygon Part

  // this is the Shape that is shown during a drawing operation
  private _temporaryShape: go.Shape = go.GraphObject.make(go.Shape, { name: 'SHAPE', fill: 'lightgray', strokeWidth: 1.5 });
  // the Shape has to be inside a temporary Part that is used during the drawing operation
  private temp: go.Part = go.GraphObject.make(go.Part, { layerName: 'Tool' }, this._temporaryShape);

  /**
   * Constructs an PolygonDrawingTool and sets the name for the tool.
   */
  constructor() {
    super();
    this.name = 'PolygonDrawing';
  }

  /**
   * Gets or sets whether this tools draws a filled polygon or an unfilled open polyline.
   *
   * The default value is true.
   */
  get isPolygon(): boolean { return this._isPolygon; }
  set isPolygon(val: boolean) { this._isPolygon = val; }


  /**
   * Gets or sets whether this tool draws shapes with quadratic bezier curves for each segment, or just straight lines.
   *
   * The default value is false -- only use straight lines.
   */
  get hasArcs(): boolean { return this._hasArcs; }
  set hasArcs(val: boolean) { this._hasArcs = val; }

  /**
   * Gets or sets whether this tool draws shapes with only orthogonal segments, or segments in any direction.
   * The default value is false -- draw segments in any direction. This does not restrict the closing segment, which may not be orthogonal.
   */
  get isOrthoOnly(): boolean { return this._isOrthoOnly; }
  set isOrthoOnly(val: boolean) { this._isOrthoOnly = val; }

  /**
   * Gets or sets whether this tool only places the shape's corners on the Diagram's visible grid.
   * The default value is false
   */
  get isGridSnapEnabled(): boolean { return this._isGridSnapEnabled; }
  set isGridSnapEnabled(val: boolean) { this._isGridSnapEnabled = val; }

  /**
   * Gets or sets the node data object that is copied and added to the model
   * when the drawing operation completes.
   */
  get archetypePartData(): go.ObjectData { return this._archetypePartData; }
  set archetypePartData(val: go.ObjectData) { this._archetypePartData = val; }

  /**
   * Gets or sets the Shape that is used to hold the line as it is being drawn.
   *
   * The default value is a simple Shape drawing an unfilled open thin black line.
   */
  get temporaryShape(): go.Shape { return this._temporaryShape; }
  set temporaryShape(val: go.Shape) {
    if (this._temporaryShape !== val && val !== null) {
      val.name = 'SHAPE';
      const panel = this._temporaryShape.panel;
      if (panel !== null) {
        if (panel !== null) panel.remove(this._temporaryShape);
        this._temporaryShape = val;
        if (panel !== null) panel.add(this._temporaryShape);
      }
    }
  }

  /**
   * Don't start this tool in a mode-less fashion when the user's mouse-down is on an existing Part.
   * When this tool is a mouse-down tool, it requires using the left mouse button in the background of a modifiable Diagram.
   * Modal uses of this tool will not call this canStart predicate.
   */
  public canStart(): boolean {
    if (!this.isEnabled) return false;
    const diagram = this.diagram;
    if (diagram.isReadOnly || diagram.isModelReadOnly) return false;
    const model = diagram.model;
    if (model === null) return false;
    // require left button
    if (!diagram.firstInput.left) return false;
    // can't start when mouse-down on an existing Part
    const obj = diagram.findObjectAt(diagram.firstInput.documentPoint, null, null);
    return (obj === null);
  }

  /**
  * Start a transaction, capture the mouse, use a "crosshair" cursor,
  * and start accumulating points in the geometry of the {@link #temporaryShape}.
  * @this {PolygonDrawingTool}
  */
  public doStart() {
    super.doStart();
    var diagram = this.diagram;
    if (!diagram) return;
    this.startTransaction(this.name);
    diagram.currentCursor = diagram.defaultCursor = "crosshair";
    if (!diagram.lastInput.isTouchEvent) diagram.isMouseCaptured = true;
  }

  /**
   * Start a transaction, capture the mouse, use a "crosshair" cursor,
   * and start accumulating points in the geometry of the {@link #temporaryShape}.
   */
  public doActivate(): void {
    super.doActivate();
    var diagram = this.diagram;
    if (!diagram) return;
    // the first point
    if (!diagram.lastInput.isTouchEvent) this.addPoint(diagram.lastInput.documentPoint);
  }

  /**
   * Stop the transaction and clean up.
   */
  public doStop(): void {
    super.doStop();
    var diagram = this.diagram;
    if (!diagram) return;
    diagram.currentCursor = diagram.defaultCursor = "auto";
    if (this.temporaryShape !== null && this.temporaryShape.part !== null) {
      diagram.remove(this.temporaryShape.part);
    }
    if (diagram.isMouseCaptured) diagram.isMouseCaptured = false;
    this.stopTransaction();
  }

 /**
  * @hidden @internal
  * Given a potential Point for the next segment, return a Point it to snap to the grid, and remain orthogonal, if either is applicable.
  */
  public modifyPointForGrid(p: go.Point): go.Point {
    const pregrid = p.copy();
    const grid = this.diagram.grid;
    if (grid !== null && grid.visible && this.isGridSnapEnabled) {
      const cell = grid.gridCellSize;
      const orig = grid.gridOrigin;
      p = p.copy();
      p.snapToGrid(orig.x, orig.y, cell.width, cell.height); // compute the closest grid point (modifies p)
    }
    if (this.temporaryShape.geometry === null) return p;
    const geometry = this.temporaryShape.geometry;
    if (geometry === null) return p;
    const fig = geometry.figures.first();
    if (fig === null) return p;
    const segments = fig.segments;
    if (this.isOrthoOnly && segments.count > 0) {
      let lastPt = new go.Point(fig.startX, fig.startY); // assuming segments.count === 1
      if (segments.count > 1) {
        // the last segment is the current temporary segment, which we might be altering. We want the segment before
        const secondLastSegment = (segments.elt(segments.count - 2));
        lastPt = new go.Point(secondLastSegment.endX, secondLastSegment.endY);
      }
      if (pregrid.distanceSquared(lastPt.x, pregrid.y) < pregrid.distanceSquared(pregrid.x, lastPt.y)) { // closer to X coord
        return new go.Point(lastPt.x, p.y);
      } else { // closer to Y coord
        return new go.Point(p.x, lastPt.y);
      }
    }
    return p;
  }


  /**
   * @hidden @internal
   * This internal method adds a segment to the geometry of the {@link #temporaryShape}.
   */
  public addPoint(p: go.Point): void {
    const diagram = this.diagram;
    const shape = this.temporaryShape;
    if (shape === null) return;

    // for the temporary Shape, normalize the geometry to be in the viewport
    const viewpt = diagram.viewportBounds.position;
    const q = this.modifyPointForGrid(new go.Point(p.x - viewpt.x, p.y - viewpt.y));

    const part = shape.part;
    let geo: go.Geometry | null = null;
    // if it's not in the Diagram, re-initialize the Shape's geometry and add the Part to the Diagram
    if (part !== null && part.diagram === null) {
      const fig = new go.PathFigure(q.x, q.y, true);  // possibly filled, depending on Shape.fill
      geo = new go.Geometry().add(fig);  // the Shape.geometry consists of a single PathFigure
      this.temporaryShape.geometry = geo;
      // position the Shape's Part, accounting for the stroke width
      part.position = viewpt.copy().offset(-shape.strokeWidth / 2, -shape.strokeWidth / 2);
      diagram.add(part);
    } else if (shape.geometry !== null) {
      // must copy whole Geometry in order to add a PathSegment
      geo = shape.geometry.copy();
      const fig = geo.figures.first();
      if (fig !== null) {
        if (this.hasArcs) {
          const lastseg = fig.segments.last();
          if (lastseg === null) {
            fig.add(new go.PathSegment(go.PathSegment.QuadraticBezier, q.x, q.y, (fig.startX + q.x) / 2, (fig.startY + q.y) / 2));
          } else {
            fig.add(new go.PathSegment(go.PathSegment.QuadraticBezier, q.x, q.y, (lastseg.endX + q.x) / 2, (lastseg.endY + q.y) / 2));
          }
        } else {
          fig.add(new go.PathSegment(go.PathSegment.Line, q.x, q.y));
        }
      }
    }
    shape.geometry = geo;
  }

  /**
   * @hidden @internal
   * This internal method changes the last segment of the geometry of the {@link #temporaryShape} to end at the given point.
   */
  public moveLastPoint(p: go.Point): void {
    p = this.modifyPointForGrid(p);
    const diagram = this.diagram;
    // must copy whole Geometry in order to change a PathSegment
    const shape = this.temporaryShape;
    if (shape.geometry === null) return;
    const geo = shape.geometry.copy();
    const fig = geo.figures.first();
    if (fig === null) return;
    const segs = fig.segments;
    if (segs.count > 0) {
      // for the temporary Shape, normalize the geometry to be in the viewport
      const viewpt = diagram.viewportBounds.position;
      const seg = segs.elt(segs.count - 1);
      // modify the last PathSegment to be the given Point p
      seg.endX = p.x - viewpt.x;
      seg.endY = p.y - viewpt.y;
      if (seg.type === go.PathSegment.QuadraticBezier) {
        let prevx = 0.0;
        let prevy = 0.0;
        if (segs.count > 1) {
          const prevseg = segs.elt(segs.count - 2);
          prevx = prevseg.endX;
          prevy = prevseg.endY;
        } else {
          prevx = fig.startX;
          prevy = fig.startY;
        }
        seg.point1X = (seg.endX + prevx) / 2;
        seg.point1Y = (seg.endY + prevy) / 2;
      }
      shape.geometry = geo;
    }
  }

  /**
   * @hidden @internal
   * This internal method removes the last segment of the geometry of the {@link #temporaryShape}.
   */
  public removeLastPoint(): void {
    // must copy whole Geometry in order to remove a PathSegment
    const shape = this.temporaryShape;
    if (shape.geometry === null) return;
    const geo = shape.geometry.copy();
    const fig = geo.figures.first();
    if (fig === null) return;
    const segs = fig.segments;
    if (segs.count > 0) {
      segs.removeAt(segs.count - 1);
      shape.geometry = geo;
    }
  }

  /**
   * Add a new node data JavaScript object to the model and initialize the Part's
   * position and its Shape's geometry by copying the {@link #temporaryShape}'s {@link Shape#geometry}.
   */
  public finishShape(): void {
    const diagram = this.diagram;
    const shape: go.Shape = this.temporaryShape;
    if (shape !== null && this.archetypePartData !== null) {
      // remove the temporary point, which is last, except on touch devices
      if (!diagram.lastInput.isTouchEvent) this.removeLastPoint();
      const tempgeo = shape.geometry;
      // require 3 points (2 segments) if polygon; 2 points (1 segment) if polyline
      if (tempgeo !== null) {
        const tempfig = tempgeo.figures.first();
        if (tempfig !== null && tempfig.segments.count >= (this.isPolygon ? 2 : 1)) {
          // normalize geometry and node position
          const viewpt = diagram.viewportBounds.position;
          const copygeo = tempgeo.copy();
          const copyfig = copygeo.figures.first();
          if (this.isPolygon && copyfig !== null) {
            // if polygon, close the last segment
            const segs = copyfig.segments;
            const seg = segs.elt(segs.count - 1);
            seg.isClosed = true;
          }
          // create the node data for the model
          const d = diagram.model.copyNodeData(this.archetypePartData);
          if (d !== null) {
            // adding data to model creates the actual Part
            diagram.model.addNodeData(d);
            const part = diagram.findPartForData(d);
            if (part !== null) {
              // assign the position for the whole Part
              const pos = copygeo.normalize();
              pos.x = viewpt.x - pos.x - shape.strokeWidth / 2;
              pos.y = viewpt.y - pos.y - shape.strokeWidth / 2;
              part.position = pos;
              // assign the Shape.geometry
              const pShape: go.Shape = part.findObject('SHAPE') as go.Shape;
              if (pShape !== null) pShape.geometry = copygeo;
              this.transactionResult = this.name;
            }
          }
        }
      }
    }
    this.stopTool();
  }

  /**
   * Add another point to the geometry of the {@link #temporaryShape}.
   */
  public doMouseDown(): void {
    const diagram = this.diagram;
    if (!this.isActive) {
      this.doActivate();
    }
    // a new temporary end point, the previous one is now "accepted"
    this.addPoint(diagram.lastInput.documentPoint);
    if (!diagram.lastInput.left) {  // e.g. right mouse down
      this.finishShape();
    } else if (diagram.lastInput.clickCount > 1) {  // e.g. double-click
      this.removeLastPoint();
      this.finishShape();
    }
  }

  /**
   * Move the last point of the {@link #temporaryShape}'s geometry to follow the mouse point.
   */
  public doMouseMove(): void {
    const diagram = this.diagram;
    if (this.isActive) {
      this.moveLastPoint(diagram.lastInput.documentPoint);
    }
  }

  /**
   * Do not stop this tool, but continue to accumulate Points via mouse-down events.
   */
  public doMouseUp(): void {
    // don't stop this tool (the default behavior is to call stopTool)
  }

  /**
   * Typing the "ENTER" key accepts the current geometry (excluding the current mouse point)
   * and creates a new part in the model by calling {@link #finishShape}.
   *
   * Typing the "Z" key causes the previous point to be discarded.
   *
   * Typing the "ESCAPE" key causes the temporary Shape and its geometry to be discarded and this tool to be stopped.
   */
  public doKeyDown(): void {
    const diagram = this.diagram;
    if (!this.isActive) return;
    const e = diagram.lastInput;
    if (e.key === '\r') {  // accept
      this.finishShape();  // all done!
    } else if (e.key === 'Z') {  // undo
      this.undo();
    } else {
      super.doKeyDown();
    }
  }

  /**
   * Undo: remove the last point and continue the drawing of new points.
   */
  public undo(): void {
    const diagram = this.diagram;
    // remove a point, and then treat the last one as a temporary one
    this.removeLastPoint();
    const lastInput = diagram.lastInput;
    if (lastInput.event instanceof MouseEvent) this.moveLastPoint(lastInput.documentPoint);
  }
}