@quartic/bokehjs/test/core/util/math.coffee

Interactive, novel data visualization

{expect} = require "chai"
utils = require "../../utils"

math = utils.require("core/util/math")

describe "math module", ->

  it "should return angle normalized between 0 and 2*Math.PI inclusive", ->
    expect(math.angle_norm(3*Math.PI)).to.be.closeTo(Math.PI, 0.000001)
    expect(math.angle_norm(-3*Math.PI)).to.be.closeTo(Math.PI, 0.000001)
    expect(math.angle_norm(0)).to.be.closeTo(0, 0.000001)

  it "should return the distance between two angles as a positive radian", ->
    expect(math.angle_dist(2.5*Math.PI, -2.5*Math.PI)).to.be.closeTo(Math.PI, 0.000001)
    expect(math.angle_dist(-2.5*Math.PI, 2.5*Math.PI)).to.be.closeTo(Math.PI, 0.000001)

  it "should return true if `mid` angle between `lhs` and `rhs`", ->
    expect(math.angle_between(0, -1, 1, "anticlock")).to.be.equal(false)
    expect(math.angle_between(0, -1, 1, "clock")).to.be.equal(true)

  it "should return the arctangent between 2 (x,y) points", ->
    expect(math.atan2([0,0],[0,1])).to.be.closeTo(Math.PI/2, 0.0000001) # vertical up
    expect(math.atan2([0,0],[0,-1])).to.be.closeTo(-Math.PI/2, 0.0000001) # vertical down
    expect(math.atan2([0,0],[1,0])).to.be.closeTo(0, 0.0000001) # horizontal right
    expect(math.atan2([0,0],[-1,0])).to.be.closeTo(Math.PI, 0.0000001) # horizontal left
    expect(math.atan2([1,1],[2,2])).to.be.closeTo(Math.PI/4, 0.0000001)

  it "should clamp between min and max values", ->
    expect(math.clamp(0, -1, 1)).to.be.equal(0)
    expect(math.clamp(1, -1, 1)).to.be.equal(1)
    expect(math.clamp(2, -1, 1)).to.be.equal(1)
    expect(math.clamp(-1, -1, 1)).to.be.equal(-1)
    expect(math.clamp(-2, -1, 1)).to.be.equal(-1)

    expect(math.clamp(0, 1, 2)).to.be.equal(1)
    expect(math.clamp(1, 1, 2)).to.be.equal(1)
    expect(math.clamp(-1, 1, 2)).to.be.equal(1)
    expect(math.clamp(1.5, 1, 2)).to.be.equal(1.5)
    expect(math.clamp(2, 1, 2)).to.be.equal(2)
    expect(math.clamp(3, 1, 2)).to.be.equal(2)