/**
@page tablet-support Tablet support

This page provides details about the graphics tablet
support in libinput. Note that the term "tablet" in libinput refers to
graphics tablets only (e.g. Wacom Intuos), not to tablet devices like the
Apple iPad.

@section fake-proximity Handling of proximity events

libinput's @ref LIBINPUT_EVENT_TABLET_PROXIMITY events represent the
physical proximity limits of the device. In some cases the caller should
emulate proximity based on the distance events. For example, the Wacom mouse
and lens cursor tools are usually used in relative mode, lying flat on the
tablet. A user typically expects that lifting the tool off the tablet to a
different location has the same effect as with a normal mouse. The proximity
detection on Wacom tablets however extends further than the user may lift
the mouse, i.e. the tool may not be lifted out of physical proximity.

To enable normal use as a mouse it is recommended that the caller treats
proximity separate from libinput's proximity events. There is no simple way
to detect the proximity motion threshold, it is different on each tablet and
differs between tools. The recommended algorithm is to remember the minimum
distance value seen on the tool and assume a proximity out when the distance
exceeds a threshold above this minimum value. In pseudo-code:

@code
const double threshold = ...;
static double min;
static bool in_proximity;

double value;

value = libinput_event_pointer_get_axis_value(device,
					      LIBINPUT_TABLET_AXIS_DISTANCE);

if (value < min) {
	min = value;
	return;
} else if (in_proximity &&
	   value > min + threshold) {
	   in_proximity = false;
} else if (!in_proximity &&
	   value < min + threshold) {
	   in_proximity = true;
}
@endcode

*/