plotboilerplate
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A simple javascript plotting boilerplate for 2d stuff.
135 lines • 4.74 kB
JavaScript
/**
* @author Ikaros Kappler
* @date 2016-03-12
* @modified 2018-12-05 Refactored the code from the morley-triangle script.
* @modified 2019-03-20 Added JSDoc tags.
* @modified 2019-04-28 Fixed a bug in the Line.sub( Vertex ) function (was not working).
* @modified 2019-09-02 Added the Line.add( Vertex ) function.
* @modified 2019-09-02 Added the Line.denominator( Line ) function.
* @modified 2019-09-02 Added the Line.colinear( Line ) function.
* @modified 2019-09-02 Fixed an error in the Line.intersection( Line ) function (class Point was renamed to Vertex).
* @modified 2019-12-15 Added the Line.moveTo(Vertex) function.
* @modified 2020-03-16 The Line.angle(Line) parameter is now optional. The baseline (x-axis) will be used if not defined.
* @modified 2020-03-23 Ported to Typescript from JS.
* @modified 2020-12-04 The `intersection` function returns undefined if both lines are parallel.
* @modified 2022-02-02 Added the `destroy` method.
* @modified 2022-10-09 Changed the actual return value of the `intersection` function to null (was undefined before).
* @modified 2022-10-17 Adding these methods from the `PathSegment` interface: getStartPoint, getEndPoint, revert.
* @modified 2023-09-25 Changed param type of `intersection()` from Line to VertTuple.
* @version 2.3.0
*
* @file Line
* @public
**/
import { VertTuple } from "./VertTuple";
import { Vertex } from "./Vertex";
/**
* @classdesc A line consists of two vertices a and b.<br>
* <br>
* This is some refactored code from my 'Morley Triangle' test<br>
* https://github.com/IkarosKappler/morleys-trisector-theorem
*
* @requires Vertex
*/
export class Line extends VertTuple {
/**
* Creates an instance of Line.
*
* @constructor
* @name Line
* @param {Vertex} a The line's first point.
* @param {Vertex} b The line's second point.
**/
constructor(a, b) {
super(a, b, (a, b) => new Line(a, b));
/**
* Required to generate proper CSS classes and other class related IDs.
**/
this.className = "Line";
}
/**
* Get the intersection if this line and the specified line.
*
* @method intersection
* @param {Line} line The second line.
* @return {Vertex|undefined} The intersection (may lie outside the end-points) or `undefined` if both lines are parallel.
* @instance
* @memberof Line
**/
// !!! DO NOT MOVE TO VertTuple
intersection(line) {
const denominator = this.denominator(line);
if (denominator == 0) {
return null;
}
let a = this.a.y - line.a.y;
let b = this.a.x - line.a.x;
const numerator1 = (line.b.x - line.a.x) * a - (line.b.y - line.a.y) * b;
const numerator2 = (this.b.x - this.a.x) * a - (this.b.y - this.a.y) * b;
a = numerator1 / denominator; // NaN if parallel lines
b = numerator2 / denominator;
// Catch NaN?
const x = this.a.x + a * (this.b.x - this.a.x);
const y = this.a.y + a * (this.b.y - this.a.y);
if (isNaN(a) || isNaN(x) || isNaN(y)) {
return null;
}
// if we cast these lines infinitely in both directions, they intersect here:
return new Vertex(x, y);
}
//--- Implement PathSegment ---
/**
* Get the start point of this path segment.
*
* @method getStartPoint
* @memberof PathSegment
* @return {Vertex} The start point of this path segment.
*/
getStartPoint() {
return this.a;
}
/**
* Get the end point of this path segment.
*
* @method getEndPoint
* @memberof PathSegment
* @return {Vertex} The end point of this path segment.
*/
getEndPoint() {
return this.b;
}
/**
* Get the tangent's end point at the start point of this segment.
*
* @method getStartTangent
* @memberof PathSegment
* @return {Vertex} The end point of the starting point's tangent.
*/
getStartTangent() {
return this.b;
}
/**
* Get the tangent's end point at the end point of this segment.
*
* @method getEndTangent
* @memberof PathSegment
* @return {Vertex} The end point of the ending point's tangent.
*/
getEndTangent() {
return this.a;
}
/**
* Inverse this path segment (in-place) and return this same instance (useful for chaining).
*
* @method reverse
* @memberof PathSegment
* @return {PathSegment} This path segment instance (for chaining).
*/
reverse() {
var tmp = this.a;
this.a = this.b;
this.b = tmp;
return this;
}
}
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