flatten-js
Version:
Javascript library for 2d geometry
296 lines (256 loc) • 10.8 kB
JavaScript
/**
* Created by Alex Bol on 2/18/2017.
*/
/**
*
* @param Flatten
*/
module.exports = function(Flatten) {
/**
*
* Class representing a point
* @type {Point}
*/
Flatten.Point = class Point {
/**
* 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) {
/**
* 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 Flatten.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);
}
/**
* Method clone returns new copied 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.y <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;
}
/**
* Returns new point rotated by given angle around given center point.
* If center point is omitted, rotates around zero point (0,0).
* Positive value of angle defines rotation in counter clockwise direction,
* negative angle defines rotation in clockwise clockwise direction
* @param {number} angle - angle in radians
* @param {Point} [center=(0,0)] center
* @returns {Point}
*/
rotate(angle, center = {x:0, y:0}) {
var x_rot = center.x + (this.x - center.x) * Math.cos(angle) - (this.y - center.y) * Math.sin(angle);
var y_rot = center.y + (this.x - center.x) * Math.sin(angle) + (this.y - center.y) * Math.cos(angle);
return new Flatten.Point(x_rot, y_rot);
}
/**
* Returns new point translated by given vector.
* Translation vector may by also defined by a pair of numbers.
* @param {Vector} vector - Translation vector defined as Flatten.Vector or
* @param {number|number} - Translation vector defined as pair of numbers
* @returns {Point}
*/
translate(...args) {
if (args.length == 1 && (args[0] instanceof Flatten.Vector)) {
return new Flatten.Point(this.x + args[0].x, this.y + args[0].y);
}
if (args.length == 2 && typeof(args[0]) == "number" && typeof(args[1]) == "number") {
return new Flatten.Point(this.x + args[0], this.y + args[1]);
}
throw Flatten.Errors.ILLEGAL_PARAMETERS;
}
/**
* Return new point transformed by affine transformation matrix m
* @param {Matrix} m - affine transformation matrix (a,b,c,d,tx,ty)
* @returns {Point}
*/
transform(m) {
// let [x,y] = m.transform([this.x,this.y]);
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) {
let {Distance} = Flatten;
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 Distance.point2line(this, shape);
}
if (shape instanceof Flatten.Circle) {
return Distance.point2circle(this, shape);
}
if (shape instanceof Flatten.Segment) {
return Distance.point2segment(this, shape);
}
if (shape instanceof Flatten.Arc) {
// let [dist, ...rest] = Distance.point2arc(this, shape);
// return dist;
return Distance.point2arc(this, shape);
}
if (shape instanceof Flatten.Polygon) {
// let [dist, ...rest] = Distance.point2polygon(this, shape);
// return dist;
return Distance.point2polygon(this, shape);
}
if (shape instanceof Flatten.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 Flatten.Point) {
return this.equalTo(shape);
}
if (shape instanceof Flatten.Line) {
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);
}
}
/**
* 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 = {}) {
let {r, stroke, strokeWidth, fill, id, className} = attrs;
// let rest_str = Object.keys(rest).reduce( (acc, key) => acc += ` ${key}="${rest[key]}"`, "");
let id_str = (id && id.length > 0) ? `id="${id}"` : "";
let class_str = (className && className.length > 0) ? `class="${className}"` : "";
return `\n<circle cx="${this.x}" cy="${this.y}" r="${r || 3}" stroke="${stroke || "black"}" stroke-width="${strokeWidth || 1}" fill="${fill || "red"}" ${id_str} ${class_str} />`;
}
/**
* This method returns an object that defines how data will be
* serialized when called JSON.stringify() method
* @returns {Object}
*/
toJSON() {
return Object.assign({},this,{name:"point"});
}
};
/**
* Function to create point equivalent to "new" constructor
* @param args
*/
Flatten.point = (...args) => new Flatten.Point(...args);
};