It seems the existing getScaleX/getScaleY method in AffineTransform.java only returns the m00/m11 element of the 3x3 affine transformation matrix which controls the contribution of input X coordinates to the output X coordinates.
This value is not the entire scaling factor applied to X coordinates since it ignores any contribution from the input Y coordinates under rotations
We need to use
{getScalingFactorX} to compute how much X coordinates are stretched or contracted by the full transformation matrix.