@zenghawtin/graph2d
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Javascript library for 2d geometry
258 lines (222 loc) • 7.6 kB
JavaScript
/**
* Created by Alex Bol on 2/18/2017.
*/
import Flatten from '../flatten';
import {convertToString} from "../utils/attributes";
import {Matrix} from "./matrix";
import {Shape} from "./shape";
import {Errors} from "../utils/errors";
/**
*
* Class representing a point
* @type {Point}
*/
export class Point extends Shape {
/**
* Point may be constructed by two numbers, or by array of two numbers
* @param {number} x - x-coordinate (float number)
* @param {number} y - y-coordinate (float number)
*/
constructor(...args) {
super()
/**
* x-coordinate (float number)
* @type {number}
*/
this.x = 0;
/**
* y-coordinate (float number)
* @type {number}
*/
this.y = 0;
if (args.length === 0) {
return;
}
if (args.length === 1 && args[0] instanceof Array && args[0].length === 2) {
let arr = args[0];
if (typeof (arr[0]) == "number" && typeof (arr[1]) == "number") {
this.x = arr[0];
this.y = arr[1];
return;
}
}
if (args.length === 1 && args[0] instanceof Object && args[0].name === "point") {
let {x, y} = args[0];
this.x = x;
this.y = y;
return;
}
if (args.length === 2) {
if (typeof (args[0]) == "number" && typeof (args[1]) == "number") {
this.x = args[0];
this.y = args[1];
return;
}
}
throw Errors.ILLEGAL_PARAMETERS;
}
/**
* Returns bounding box of a point
* @returns {Box}
*/
get box() {
return new Flatten.Box(this.x, this.y, this.x, this.y);
}
/**
* Return new cloned instance of point
* @returns {Point}
*/
clone() {
return new Flatten.Point(this.x, this.y);
}
get vertices() {
return [this.clone()];
}
/**
* Returns true if points are equal up to [Flatten.Utils.DP_TOL]{@link DP_TOL} tolerance
* @param {Point} pt Query point
* @returns {boolean}
*/
equalTo(pt) {
return Flatten.Utils.EQ(this.x, pt.x) && Flatten.Utils.EQ(this.y, pt.y);
}
/**
* Defines predicate "less than" between points. Returns true if the point is less than query points, false otherwise <br/>
* By definition point1 < point2 if {point1.y < point2.y || point1.y == point2.y && point1.x < point2.x <br/>
* Numeric values compared with [Flatten.Utils.DP_TOL]{@link DP_TOL} tolerance
* @param {Point} pt Query point
* @returns {boolean}
*/
lessThan(pt) {
if (Flatten.Utils.LT(this.y, pt.y))
return true;
if (Flatten.Utils.EQ(this.y, pt.y) && Flatten.Utils.LT(this.x, pt.x))
return true;
return false;
}
/**
* Return new point transformed by affine transformation matrix
* @param {Matrix} m - affine transformation matrix (a,b,c,d,tx,ty)
* @returns {Point}
*/
transform(m) {
return new Flatten.Point(m.transform([this.x, this.y]))
}
/**
* Returns projection point on given line
* @param {Line} line Line this point be projected on
* @returns {Point}
*/
projectionOn(line) {
if (this.equalTo(line.pt)) // this point equal to line anchor point
return this.clone();
let vec = new Flatten.Vector(this, line.pt);
if (Flatten.Utils.EQ_0(vec.cross(line.norm))) // vector to point from anchor point collinear to normal vector
return line.pt.clone();
let dist = vec.dot(line.norm); // signed distance
let proj_vec = line.norm.multiply(dist);
return this.translate(proj_vec);
}
/**
* Returns true if point belongs to the "left" semi-plane, which means, point belongs to the same semi plane where line normal vector points to
* Return false if point belongs to the "right" semi-plane or to the line itself
* @param {Line} line Query line
* @returns {boolean}
*/
leftTo(line) {
let vec = new Flatten.Vector(line.pt, this);
let onLeftSemiPlane = Flatten.Utils.GT(vec.dot(line.norm), 0);
return onLeftSemiPlane;
}
/**
* Calculate distance and shortest segment from point to shape and return as array [distance, shortest segment]
* @param {Shape} shape Shape of the one of supported types Point, Line, Circle, Segment, Arc, Polygon or Planar Set
* @returns {number} distance from point to shape
* @returns {Segment} shortest segment between point and shape (started at point, ended at shape)
*/
distanceTo(shape) {
if (shape instanceof Point) {
let dx = shape.x - this.x;
let dy = shape.y - this.y;
return [Math.sqrt(dx * dx + dy * dy), new Flatten.Segment(this, shape)];
}
if (shape instanceof Flatten.Line) {
return Flatten.Distance.point2line(this, shape);
}
if (shape instanceof Flatten.Circle) {
return Flatten.Distance.point2circle(this, shape);
}
if (shape instanceof Flatten.Segment) {
return Flatten.Distance.point2segment(this, shape);
}
if (shape instanceof Flatten.Arc) {
return Flatten.Distance.point2arc(this, shape);
}
if (shape instanceof Flatten.Polygon) {
return Flatten.Distance.point2polygon(this, shape);
}
if (shape instanceof Flatten.PlanarSet) {
return Flatten.Distance.shape2planarSet(this, shape);
}
}
/**
* Returns true if point is on a shape, false otherwise
* @param {Shape} shape
* @returns {boolean}
*/
on(shape) {
if (shape instanceof Flatten.Point) {
return this.equalTo(shape);
}
if (shape instanceof Flatten.Box) {
return shape.contains(this);
}
if (shape instanceof Flatten.Line) {
return shape.contains(this);
}
if (shape instanceof Flatten.Ray) {
return shape.contains(this)
}
if (shape instanceof Flatten.Circle) {
return shape.contains(this);
}
if (shape instanceof Flatten.Segment) {
return shape.contains(this);
}
if (shape instanceof Flatten.Arc) {
return shape.contains(this);
}
if (shape instanceof Flatten.Polygon) {
return shape.contains(this);
}
}
get name() {
return "point"
}
/**
* Return string to draw point in svg as circle with radius "r" <br/>
* Accept any valid attributes of svg elements as svg object
* Defaults attribues are: <br/>
* {
* r:"3",
* stroke:"black",
* strokeWidth:"1",
* fill:"red"
* }
* @param {Object} attrs - Any valid attributes of svg circle element, like "r", "stroke", "strokeWidth", "fill"
* @returns {String}
*/
svg(attrs = {}) {
const r = attrs.r ?? 3 // default radius - 3
return `\n<circle cx="${this.x}" cy="${this.y}" r="${r}"
${convertToString({fill: "red", ...attrs})} />`;
}
}
Flatten.Point = Point;
/**
* Function to create point equivalent to "new" constructor
* @param args
*/
export const point = (...args) => new Flatten.Point(...args);
Flatten.point = point;
// export {Point};