DimensioningLink.js

"use strict";
/*
*  Copyright (C) 1998-2016 by Northwoods Software Corporation. All Rights Reserved.
*/

// A custom routed Link for showing the distances between a point on one node and a point on another node.

// Note that because this is a Link, the points being measured must be on Nodes, not simple Parts.
// The exact point on each Node is determined by the Link.fromSpot and Link.toSpot.

// Several properties of the DimensioningLink customize the appearance of the dimensioning:
// direction, for orientation of the dimension line and which side it is on,
// extension, for how far the dimension line is from the measured points,
// inset, for leaving room for a text label, and
// gap, for distance that the extension line starts from the measured points

/**
* @constructor
* @extends Link
* @class
*/
function DimensioningLink() {
  go.Link.call(this);
  this.routing = go.Link.Orthogonal;
  /** @type {number} */
  this._direction = 0;
  /** @type {number} */
  this._extension = 30;
  /** @type {number} */
  this._inset = 10;
  /** @type {number} */
  this._gap = 10;
}
go.Diagram.inherit(DimensioningLink, go.Link);

/*
* The general angle at which the measurement should be made.
* The default value is 0, meaning to go measure only along the X axis,
* with the dimension line and label above the two nodes (at lower Y coordinates).
* New values must be one of: 0, 90, 180, 270, or NaN.
* The value NaN indicates that the measurement is point-to-point and not orthogonal.
* @name DimensioningLink#direction
* @function.
* @return {number}
*/
Object.defineProperty(DimensioningLink.prototype, "direction", {
  get: function() { return this._direction; },
  set: function(value) {
    if (isNaN(value) || value === 0 || value === 90 || value === 180 || value === 270) {
      this._direction = value;
    } else {
      throw new Error("DimensioningLink: invalid new direction: " + value);
    }
  }
});

/*
* The distance at which the dimension line should be from the points being measured.
* The default value is 30.
* Larger values mean further away from the nodes.
* The new value must be greater than or equal to zero.
* @name DimensioningLink#extension
* @function.
* @return {number}
*/
Object.defineProperty(DimensioningLink.prototype, "extension", {
  get: function() { return this._extension; },
  set: function(value) { this._extension = value; }
});

/*
* The distance that the dimension line should be "indented" from the ends of the
* extension lines that are orthogonal to the dimension line.
* The default value is 10.
* @name DimensioningLink#inset
* @function.
* @return {number}
*/
Object.defineProperty(DimensioningLink.prototype, "inset", {
  get: function() { return this._inset; },
  set: function(value) {
    if (value >= 0) {
      this._inset = value;
    } else {
      throw new Error("DimensioningLink: invalid new inset: " + value);
    }
  }
});

/*
* The distance that the extension lines should come short of the measured points.
* The default value is 10.
* @name DimensioningLink#gap
* @function.
* @return {number}
*/
Object.defineProperty(DimensioningLink.prototype, "gap", {
  get: function() { return this._gap; },
  set: function(value) {
    if (value >= 0) {
      this._gap = value;
    } else {
      throw new Error("DimensioningLink: invalid new gap: " + value);
    }
  }
});

/**
* @override
* @return {boolean} true if it computed a route of points
*/
DimensioningLink.prototype.computePoints = function() {
  var fromnode = this.fromNode;
  if (!fromnode) return false;
  var fromport = this.fromPort;
  var fromspot = this.computeSpot(true);
  var tonode = this.toNode;
  if (!tonode) return false;
  var toport = this.toPort;
  var tospot = this.computeSpot(false);
  var frompoint = this.getLinkPoint(fromnode, fromport, fromspot, true, true, tonode, toport);
  if (!frompoint.isReal()) return false;
  var topoint = this.getLinkPoint(tonode, toport, tospot, false, true, fromnode, fromport);
  if (!topoint.isReal()) return false;

  this.clearPoints();

  var ang = this.direction;
  if (isNaN(ang)) {
    ang = frompoint.directionPoint(topoint);
    var p = new go.Point(this.extension, 0);
    p.rotate(ang + 90);
    var q = new go.Point(this.extension - this.inset, 0);
    q.rotate(ang + 90);
    var g = new go.Point(this.gap, 0);
    g.rotate(ang + 90);
    this.addPointAt(frompoint.x + g.x, frompoint.y + g.y);
    this.addPointAt(frompoint.x + p.x, frompoint.y + p.y);
    this.addPointAt(frompoint.x + q.x, frompoint.y + q.y);
    this.addPointAt(topoint.x + q.x, topoint.y + q.y);
    this.addPointAt(topoint.x + p.x, topoint.y + p.y);
    this.addPointAt(topoint.x + g.x, topoint.y + g.y);
  } else {
    var dist = this.extension;
    var r = 0.0;
    var s = 0.0;
    var t0 = 0.0;
    var t1 = 0.0;
    if (ang === 0 || ang === 180) {
      if (ang === 0) {
        r = Math.min(frompoint.y, topoint.y) - this.extension;
        s = r + this.inset;
        t0 = frompoint.y - this.gap;
        t1 = topoint.y - this.gap;
      } else {
        r = Math.max(frompoint.y, topoint.y) + this.extension;
        s = r - this.inset;
        t0 = frompoint.y + this.gap;
        t1 = topoint.y + this.gap;
      }
      this.addPointAt(frompoint.x, t0);
      this.addPointAt(frompoint.x + 0.01, r);
      this.addPointAt(frompoint.x, s);
      this.addPointAt(topoint.x, s);
      this.addPointAt(topoint.x - 0.01, r);
      this.addPointAt(topoint.x, t1);
    } else if (ang === 90 || ang === 270) {
      if (ang === 90) {
        r = Math.max(frompoint.x, topoint.x) + this.extension;
        s = r - this.inset;
        t0 = frompoint.x + this.gap;
        t1 = topoint.x + this.gap;
      } else {
        r = Math.min(frompoint.x, topoint.x) - this.extension;
        s = r + this.inset;
        t0 = frompoint.x - this.gap;
        t1 = topoint.x - this.gap;
      }
      this.addPointAt(t0, frompoint.y);
      this.addPointAt(r, frompoint.y + 0.01);
      this.addPointAt(s, frompoint.y);
      this.addPointAt(s, topoint.y);
      this.addPointAt(r, topoint.y - 0.01);
      this.addPointAt(t1, topoint.y);
    }
  }

  this.updateTargetBindings();
  return true;
};