public abstract Rectangle get_swipe_area (NavigationDirection navigation_direction, bool is_drag)
Gets the area this can start a swipe from for the given direction and gesture type.
This can be used to restrict swipes to only be possible from a certain area, for example, to only allow edge swipes, or to have a draggable element and ignore swipes elsewhere.
Swipe area is only considered for direct swipes (as in, not initiated by SwipeGroup ).
If not implemented, the default implementation returns the allocation of this, allowing swipes from anywhere.
the direction of the swipe
whether the swipe is caused by a dragging gesture
a pointer to a Rectangle to store the swipe area