gojs
Version:
Interactive diagrams, charts, and graphs, such as trees, flowcharts, orgcharts, UML, BPMN, or business diagrams
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JavaScript
/*
* Copyright (C) 1998-2020 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';
/**
* This custom {@link Link} class customizes its {@link Shape} to surround the comment node (the from node).
* If the Shape is filled, it will obscure the comment itself unless the Link is behind the comment node.
* Thus the default layer for BalloonLinks is "Background".
*
* If you want to experiment with this extension, try the <a href="../../extensionsTS/BalloonLink.html">Balloon Links</a> sample.
* @category Part Extension
*/
export class BalloonLink extends go.Link {
/**
* Constructs a BalloonLink and sets the {@link Part#layerName} property to "Background".
*/
constructor() {
super();
this._base = 10;
this.layerName = 'Background';
}
/**
* Copies properties to a cloned BalloonLink.
*/
cloneProtected(copy) {
super.cloneProtected(copy);
copy._base = this._base;
}
/**
* Gets or sets width of the base of the triangle at the center point of the {@link Link#fromNode}.
*
* The default value is 10.
*/
get base() { return this._base; }
set base(value) { this._base = value; }
/**
* Produce a Geometry from the Link's route that draws a "balloon" shape around the {@link Link#fromNode}
* and has a triangular shape with the base at the fromNode and the top at the toNode.
*/
makeGeometry() {
const fromnode = this.fromNode;
const tonode = this.toNode;
if (fromnode === null || tonode === null)
return super.makeGeometry();
// assume the fromNode is the comment and the toNode is the commented-upon node
const bb = fromnode.actualBounds;
const nb = tonode.actualBounds;
const p0 = bb.center;
let pn = this.getPoint(this.pointsCount - 1);
if (bb.intersectsRect(nb)) {
pn = nb.center;
}
const pos = this.routeBounds;
// compute the intersection points for the triangular arrow
const ang = pn.directionPoint(p0);
const L = new go.Point(this.base, 0).rotate(ang - 90).add(p0);
const R = new go.Point(this.base, 0).rotate(ang + 90).add(p0);
this.getLinkPointFromPoint(fromnode, fromnode, L, pn, true, L);
this.getLinkPointFromPoint(fromnode, fromnode, R, pn, true, R);
// form a triangular arrow from the comment to the commented node
const fig = new go.PathFigure(pn.x - pos.x, pn.y - pos.y, true); // filled; start at arrow point at commented node
fig.add(new go.PathSegment(go.PathSegment.Line, R.x - pos.x, R.y - pos.y)); // a triangle base point on comment's edge
let side = 0;
if (L.y >= bb.bottom || R.y >= bb.bottom)
side = 2;
else if (L.x <= bb.x && R.x <= bb.x)
side = 1;
else if (L.x >= bb.right && R.x >= bb.right)
side = 3;
this.pathToCorner(side, bb, fig, pos, L, R);
this.pathToCorner(side + 1, bb, fig, pos, L, R);
this.pathToCorner(side + 2, bb, fig, pos, L, R);
this.pathToCorner(side + 3, bb, fig, pos, L, R);
fig.add(new go.PathSegment(go.PathSegment.Line, L.x - pos.x, L.y - pos.y).close()); // the other triangle base point on comment's edge
// return a Geometry
return new go.Geometry().add(fig);
}
/**
* Draw a line to a corner, but not if the comment arrow encompasses that corner.
*/
pathToCorner(side, bb, fig, pos, L, R) {
switch (side % 4) {
case 0:
if (!(L.y <= bb.y && R.x <= bb.x))
fig.add(new go.PathSegment(go.PathSegment.Line, bb.x - pos.x, bb.y - pos.y));
break;
case 1:
if (!(L.x <= bb.x && R.y >= bb.bottom))
fig.add(new go.PathSegment(go.PathSegment.Line, bb.x - pos.x, bb.bottom - pos.y));
break;
case 2:
if (!(L.y >= bb.bottom && R.x >= bb.right))
fig.add(new go.PathSegment(go.PathSegment.Line, bb.right - pos.x, bb.bottom - pos.y));
break;
case 3:
if (!(L.x >= bb.right && R.y <= bb.y))
fig.add(new go.PathSegment(go.PathSegment.Line, bb.right - pos.x, bb.y - pos.y));
break;
}
}
}