romgrk-2d-geometry
Version:
Javascript library for 2d geometry
209 lines (208 loc) • 7.27 kB
JavaScript
import Errors from "../utils/errors";
import { convertToString } from "../utils/attributes";
import * as Distance from '../algorithms/distance';
import * as Utils from "../utils/utils";
import * as geom from './index';
import { Shape } from "./Shape";
/**
* 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();
this.x = 0;
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) {
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 geom.Box(this.x, this.y, this.x, this.y);
}
/**
* Return new cloned instance of point
* @returns {Point}
*/
clone() {
return new Point(this.x, this.y);
}
get vertices() {
return [this.clone()];
}
/**
* Returns true if points are equal up to [Utils.DP_TOL]{@link DP_TOL} tolerance
* @param {Point} pt Query point
* @returns {boolean}
*/
equalTo(pt) {
return Utils.EQ(this.x, pt.x) && 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 [Utils.DP_TOL]{@link DP_TOL} tolerance
* @param {Point} pt Query point
* @returns {boolean}
*/
lessThan(pt) {
if (Utils.LT(this.y, pt.y))
return true;
if (Utils.EQ(this.y, pt.y) && 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 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 geom.Vector(this, line.pt);
if (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 geom.Vector(line.pt, this);
let onLeftSemiPlane = Utils.GT(vec.dot(line.norm), 0);
return onLeftSemiPlane;
}
snapToGrid(a = 1, b) {
const xGrid = a;
const yGrid = b === undefined ? a : b;
return new Point(Math.round(this.x / xGrid) * xGrid, Math.round(this.y / yGrid) * yGrid);
}
/**
* 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 geom.Segment(this, shape)];
}
if (shape instanceof geom.Line) {
return Distance.point2line(this, shape);
}
if (shape instanceof geom.Circle) {
return Distance.point2circle(this, shape);
}
if (shape instanceof geom.Segment) {
return Distance.point2segment(this, shape);
}
if (shape instanceof geom.Arc) {
return Distance.point2arc(this, shape);
}
if (shape instanceof geom.Polygon) {
return Distance.point2polygon(this, shape);
}
// TODO: enable
// if (shape instanceof PlanarSet) {
// return Distance.shape2planarSet(this, shape);
// }
}
/**
* Returns true if point is on a shape, false otherwise
* @param {Shape} shape Shape of the one of supported types Point, Line, Circle, Segment, Arc, Polygon
* @returns {boolean}
*/
on(shape) {
if (shape instanceof geom.Point) {
return this.equalTo(shape);
}
if (shape instanceof geom.Line) {
return shape.contains(this);
}
if (shape instanceof geom.Ray) {
return shape.contains(this);
}
if (shape instanceof geom.Circle) {
return shape.contains(this);
}
if (shape instanceof geom.Segment) {
return shape.contains(this);
}
if (shape instanceof geom.Arc) {
return shape.contains(this);
}
if (shape instanceof geom.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 attrs - Any valid attributes of svg circle element, like "r", "stroke", "strokeWidth", "fill"
*/
svg(attrs = {}) {
var _a;
const r = (_a = attrs.r) !== null && _a !== void 0 ? _a : 3; // default radius - 3
return `\n<circle cx="${this.x}" cy="${this.y}" r="${r}"
${convertToString({ fill: "red", ...attrs })} />`;
}
}
Point.EMPTY = Object.freeze(new Point(0, 0));
export const point = (...args) => new Point(...args);