In this mode, delta values are measured in line heights. The height of a line is supplied as an argument to the PointerWheelEvent#getDeltaPixels method.
In this mode, delta values are measured in Widget dimensions, minus a few lines or a percentage of the dimensions, whichever is smaller. Both line height and dimensions are supplied as arguments to the PointerWheelEvent#getDeltaPixels method.
In this mode, delta values are measured in pixels.
The scrolling mode that determines how the PointerWheelEvent#deltaX, PointerWheelEvent#deltaY and PointerWheelEvent#deltaZ values are interpreted.