@jscad/modeling/src/geometries/path2/appendArc.test.js

Constructive Solid Geometry (CSG) Library for JSCAD

const test = require('ava')

const { TAU } = require('../../maths/constants')

const { appendArc, fromPoints, toPoints } = require('./index')

const { comparePoints } = require('../../../test/helpers/')

test('appendArc: appending to an empty path produces an error', (t) => {
  const p1 = fromPoints({}, [])
  t.throws(() => appendArc({ endpoint: [12, 12] }, p1),
    { message: 'the given path must contain one or more points (as the starting point for the arc)' })
})

test('appendArc: appending to a path produces a new path', (t) => {
  const p1 = fromPoints({}, [[1, 1], [2, 2]])
  let obs = appendArc({ endpoint: [-2, 2] }, p1)
  let pts = toPoints(obs)
  t.is(pts.length, 3)

  // test radius
  const p2 = fromPoints({}, [[27, -22], [27, -3]])
  obs = appendArc({ endpoint: [12, -22], radius: [15, -20] }, p2)
  pts = toPoints(obs)
  t.is(pts.length, 7)

  // test segments
  obs = appendArc({ endpoint: [12, -22], radius: [15, -20], segments: 64 }, p2)
  pts = toPoints(obs)
  t.is(pts.length, 19)

  // test clockwise
  obs = appendArc({ endpoint: [12, -22], radius: [15, -20], clockwise: true }, p2)
  pts = toPoints(obs)
  let exp = [
    [27, -22],
    [27, -3],
    [26.086451657912605, -8.941047736250177],
    [23.87938869625451, -14.243872270248309],
    [20.58174906029909, -18.420882475791835],
    [16.49674848226545, -21.0880050920699],
    [11.999999999999998, -22]
  ]
  t.is(pts.length, 7)
  t.true(comparePoints(pts, exp))

  // test large
  obs = appendArc({ endpoint: [12, -22], radius: [15, -20], large: true }, p2)
  pts = toPoints(obs)
  t.is(pts.length, 16)

  // test xaxisrotation
  obs = appendArc({ endpoint: [12, -22], radius: [15, -20], xaxisrotation: TAU / 4 }, p2)
  pts = toPoints(obs)
  exp = [
    [27, -22],
    [27, -3],
    [21.830323320631795, -4.401628923214028],
    [17.364704977487236, -6.805886946199115],
    [13.940501387124588, -10.031143708098092],
    [11.816394990371812, -13.833746263211978],
    [11.15285201325494, -17.926425912558045],
    [12, -22.000000000000004]
  ]
  t.is(pts.length, 8)
  t.true(comparePoints(pts, exp))

  // test small arc between far points
  obs = appendArc({ endpoint: [120, -220], radius: [5, -5] }, p2)
  pts = toPoints(obs)
  t.is(pts.length, 2)
})

test('appendArc: appending to a path produces exact endpoint', (t) => {
  let p1 = fromPoints({}, [[18, 1.8], [1, 3]])
  const endpoint = [1, -3]

  p1 = appendArc({
    endpoint,
    radius: [4, 4],
    segments: 36,
    large: true
  }, p1)

  const pts = toPoints(p1)

  t.deepEqual(pts[pts.length - 1], endpoint)
})