svgedit/cypress/e2e/unit/math.cy.js

import { NS } from '../../../packages/svgcanvas/core/namespaces.js'
import * as math from '../../../packages/svgcanvas/core/math.js'

describe('math', function () {
  const svg = document.createElementNS(NS.SVG, 'svg')

  it('Test svgedit.math package', function () {
    assert.ok(math)
    assert.ok(math.transformPoint)
    assert.ok(math.isIdentity)
    assert.ok(math.matrixMultiply)
    assert.equal(typeof math.transformPoint, typeof function () { /* empty fn */ })
    assert.equal(typeof math.isIdentity, typeof function () { /* empty fn */ })
    assert.equal(typeof math.matrixMultiply, typeof function () { /* empty fn */ })
  })

  it('Test svgedit.math.transformPoint() function', function () {
    const { transformPoint } = math

    const m = svg.createSVGMatrix()
    m.a = 1; m.b = 0
    m.c = 0; m.d = 1
    m.e = 0; m.f = 0
    let pt = transformPoint(100, 200, m)
    assert.equal(pt.x, 100)
    assert.equal(pt.y, 200)

    m.e = 300; m.f = 400
    pt = transformPoint(100, 200, m)
    assert.equal(pt.x, 400)
    assert.equal(pt.y, 600)

    m.a = 0.5; m.b = 0.75
    m.c = 1.25; m.d = 2
    pt = transformPoint(100, 200, m)
    assert.equal(pt.x, 100 * m.a + 200 * m.c + m.e)
    assert.equal(pt.y, 100 * m.b + 200 * m.d + m.f)
  })

  it('Test svgedit.math.isIdentity() function', function () {
    assert.ok(math.isIdentity(svg.createSVGMatrix()))

    const m = svg.createSVGMatrix()
    m.a = 1; m.b = 0
    m.c = 0; m.d = 1
    m.e = 0; m.f = 0
    assert.ok(math.isIdentity(m))
  })

  it('Test svgedit.math.matrixMultiply() function', function () {
    const mult = math.matrixMultiply
    const { isIdentity } = math

    // translate there and back
    const tr1 = svg.createSVGMatrix().translate(100, 50)
    const tr2 = svg.createSVGMatrix().translate(-90, 0)
    const tr3 = svg.createSVGMatrix().translate(-10, -50)
    let I = mult(tr1, tr2, tr3)
    assert.ok(isIdentity(I), 'Expected identity matrix when translating there and back')

    // rotate there and back
    // TODO: currently Mozilla fails this when rotating back at -50 and then -40 degrees
    // (b and c are *almost* zero, but not zero)
    const rotThere = svg.createSVGMatrix().rotate(90)
    const rotBack = svg.createSVGMatrix().rotate(-90) // TODO: set this to -50
    const rotBackMore = svg.createSVGMatrix().rotate(0) // TODO: set this to -40
    I = mult(rotThere, rotBack, rotBackMore)
    assert.ok(isIdentity(I), 'Expected identity matrix when rotating there and back')

    // scale up and down
    const scaleUp = svg.createSVGMatrix().scale(4)
    const scaleDown = svg.createSVGMatrix().scaleNonUniform(0.25, 1)
    const scaleDownMore = svg.createSVGMatrix().scaleNonUniform(1, 0.25)
    I = mult(scaleUp, scaleDown, scaleDownMore)
    assert.ok(isIdentity(I), 'Expected identity matrix when scaling up and down')

    // test multiplication with its inverse
    I = mult(rotThere, rotThere.inverse())
    assert.ok(isIdentity(I), 'Expected identity matrix when multiplying a matrix by its inverse')
    I = mult(rotThere.inverse(), rotThere)
    assert.ok(isIdentity(I), 'Expected identity matrix when multiplying a matrix by its inverse')
  })

  it('Test svgedit.math.transformBox() function', function () {
    const { transformBox } = math

    const m = svg.createSVGMatrix()
    m.a = 1; m.b = 0
    m.c = 0; m.d = 1
    m.e = 0; m.f = 0

    const r = transformBox(10, 10, 200, 300, m)
    assert.equal(r.tl.x, 10)
    assert.equal(r.tl.y, 10)
    assert.equal(r.tr.x, 210)
    assert.equal(r.tr.y, 10)
    assert.equal(r.bl.x, 10)
    assert.equal(r.bl.y, 310)
    assert.equal(r.br.x, 210)
    assert.equal(r.br.y, 310)
    assert.equal(r.aabox.x, 10)
    assert.equal(r.aabox.y, 10)
    assert.equal(r.aabox.width, 200)
    assert.equal(r.aabox.height, 300)
  })
})