state_mask(?State, ?Mask)

Translates between events state fields that consist of button and modifier specifications and the corresponding integer bitmasks.

State is unified with a term of the form state(Buttons, Modifiers), where Buttons is the buttons specification used by buttons_mask/2 and Modifiers is the modifiers specification used by modifiers_mask/2.

Mask is the integer bitmask representing the given set of buttons and modifiers.