A wheel_data is the event<-detail
of the wheel and horizontal_wheel events. event<-rotation
reports whole notches in the dominant direction. A wheel_data holds the
precise scroll distance in both directions since the previous wheel
event, as reported by trackpads and high resolution wheels. As the event
delegates to its detail, the methods below are normally called on the
event:
get(Ev, dy, DY)
The distances use the same sign as event<-rotation
and the unit is a notch: positive dy scrolls up (the wheel
is rotated away from the user) and positive dx scrolls
right.
<-dx
and wheel_data<-dy
are as reported by the system; negate them to obtain the physical
direction of the movement.
flipped defaults to @off.