transformation-matrix/src/inverse.js

2d transformation matrix functions written in ES6 syntax. Tree shaking ready!

/**
 * Calculate a matrix that is the inverse of the provided matrix
 * @param matrix {Matrix} Affine Matrix
 * @returns {Matrix} Inverted Affine Matrix
 */
export function inverse (matrix) {
  // http://www.wolframalpha.com/input/?i=Inverse+%5B%7B%7Ba,c,e%7D,%7Bb,d,f%7D,%7B0,0,1%7D%7D%5D

  const { a, b, c, d, e, f } = matrix

  const denom = a * d - b * c

  return {
    a: d / denom,
    b: b / -denom,
    c: c / -denom,
    d: a / denom,
    e: (d * e - c * f) / -denom,
    f: (b * e - a * f) / denom
  }
}