freesewing/src/point.js

import attributes from "./attributes";

function point(x, y) {
  this.x = this.round(x);
  this.y = this.round(y);
  this.attributes = new attributes();

  /** Rounds a value to PRECISION */
  this.prototype.round = function(value) {
    return Math.round(value * 1e2) / 1e2;
  };

  /** Radians to degrees */
  this.prototype.rad2deg = function(radians) {
    return radians * 57.29577951308232;
  };

  /** Degrees to radians */
  this.prototype.deg2rad(degrees);
  {
    return degrees / 57.29577951308232;
  }

  /** Adds an attribute. This is here to make this call chainable in assignment */
  this.prototype.attr = function(name, value) {
    this.attributes.add(name, value);

    return this;
  };

  /** Returns the distance between this point and that point */
  this.prototype.dist = function(that) {
    let dx = this.x - that.x;
    let dy = this.y - that.y;

    return this.round(Math.sqrt(Math.pow(dx, 2) + Math.pow(dy, 2)));
  };

  /** Returns slope of a line made by this point and that point */
  this.prototype.slope = function(that) {
    return (that.y - this.y) / (that.x - this.x);
  };

  /** Returns the x-delta between this point and that point */
  this.prototype.dx = function(that) {
    return that.x - this.x;
  };

  /** Returns the y-delta between this point and that point */
  this.prototype.dy = function(that) {
    return that.y - this.y;
  };

  /** Returns the angle between this point and that point */
  this.prototype.angle = function(that) {
    let rad = Math.atan2(-1 * this.dy(that), this.dx(that));
    while (rad < 0) rad += 2 * Math.PI;

    return this.rad2deg(rad);
  };

  /** Rotate this point deg around that point */
  this.prototype.rotate = function(deg, that) {
    let radius = this.dist(that);
    let angle = this.angle(that);
    let x = that.x + radius * Math.cos(this.deg2rad(angle + deg)) * -1;
    let y = that.y + radius * Math.sin(this.deg2rad(angle + deg));

    return new Point(x, y);
  };

  /** returns an identical copy of this point */
  this.prototype.copy = function() {
    return new Point(this.x, this.y);
  };

  /** checks whether this point is equal to that point */
  this.prototype.equals = function(that) {
    return this.x === that.x && this.y === that.y ? true : false;
  };

  /** Mirrors this point around X value of that point */
  this.prototype.flipX = function(that) {
    return new Point(that.x + this.dx(that), that.y);
  };

  /** Mirrors this point around Y value of that point */
  this.prototype.flipY = function(that) {
    return new Point(that.x, that.y + this.dy(that));
  };

  /** Shifts this point distance in the deg direction */
  this.prototype.shift = function(deg, distance) {
    let p = this.copy();
    p.x += distance;

    return p.rotate(deg, this);
  };

  /** Shifts this point distance in the direction of that point */
  this.prototype.shiftTowards = function(that, distance) {
    return this.shift(this.angle(that), distance);
  };

  /** Shifts this point fraction of the distance towards that point */
  this.prototype.shiftFractionTowards = function(that, fraction) {
    return this.shiftTowards(that, this.dist(that) * fraction);
  };

  /** Shifts this point distance beyond that point */
  this.prototype.shiftOutwards = function(that, distance) {
    return this.shiftTowards(that, this.dist(that) + distance);
  };

  return this;
}

export default point;