isIdentity = m =>
  m.a === 1 && m.b === 0 && m.c === 0 && m.d === 1 && m.e === 0 && m.f === 0
Checks if a matrix is the identity matrix.
@function isIdentity
@param {SVGMatrix} m - The matrix to check
@returns {boolean} True if it's an identity matrix (1,0,0,1,0,0)