This class represents a tranformation matrix.
Transformation matrices can be used to produce affine transforms
such as translations, scales, rotations and skews.
A transformation matrix consists of an array of six values.
Coordinates are expressed as a three element matrix:.
[x, y, 1].
The transformation matrix is expressed as a three by three
[a, b, 0].
[c, d, 0].
[e, f, 1].
So to apply a matrix to a point or set of points one simply
multiplies the point matrix by the transformation matrix.
This is definitively detailed in:.
The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; page 119.