Allows you access to the transform as a string.

The format of the string must be "m11, m12, m21, m22, mX, mY".

To transform a point x, y to another point x', y' the following formula is used:

  x' = (x * m11) + (y * m12) + mX
  y' = (x * m21) + (y * m22) + mY

None.