void setTo(num a, num b, num c, num d, num tx, num ty)

Source 

void setTo(num a, num b, num c, num d, num tx, num ty) {
  _data[0] = a.toDouble();
  _data[1] = b.toDouble();
  _data[2] = c.toDouble();
  _data[3] = d.toDouble();
  _data[4] = tx.toDouble();
  _data[5] = ty.toDouble();
}