Hi,

Attached files show a severe bug in calculation of a simple Type2 (exponential interpolation) function in all Acrobat versions, including the latest DC beta.

The only difference between the 2 files is the type of function used to implement the simple function ‘y = 1 – x’ to accomplish a TR function on a SoftMask that inverts the values.

The one that is correctly rendered is InvertingTRasType4.pdf which uses a Type 4 (PS) calculator function type with operators:
{ 1 exch sub }

The one that is completely wrong is InvertingTRasType2.pdf which uses a Type 2 exponential interpolation function with C0=1, C1=0 and N=1

Both function should be equivalent in the domain [0 1].