Different pen flags.
The different kind of flag states, these are flags, and can be combined.
|Indicates the pen is still in range of the pad.|
|Indicates the pen is in contact with the pad.|
|The pen is inverted.|
|Eraser is pressed.|
|The pen's 1st barrel button is held down.|
|The pen's 2nd barrel button is held down.|
|One of the physical pen's tips is touching the surface.|
|A double-click has been fired by one of the pen's barrel buttons.|