Lines Matching +full:event +full:- +full:tap
4 Multi-touch (MT) Protocol
7 :Copyright: |copy| 2009-2010 Henrik Rydberg <rydberg@euromail.se>
11 ------------
13 In order to utilize the full power of the new multi-touch and multi-user
16 document describes the multi-touch (MT) protocol which allows kernel
23 describes how to send updates for individual contacts via event slots.
30 --------------
34 packet. Since these events are ignored by current single-touch (ST)
40 event, which instructs the receiver to accept the data for the current
45 This generates an ABS_MT_SLOT event, which instructs the receiver to
48 All drivers mark the end of a multi-touch transfer by calling the usual
61 surface. The order in which the packets appear in the event stream is not
62 important. Event filtering and finger tracking is left to user space [#f3]_.
67 the ABS_MT_TRACKING_ID of the associated slot. A non-negative tracking id
68 is interpreted as a contact, and the value -1 denotes an unused slot. A
72 end. Upon receiving an MT event, one simply updates the appropriate
81 a BTN_TOOL_*TAP event to inform userspace of the total number of contacts
83 explicitly sending the corresponding BTN_TOOL_*TAP event and setting
87 by noting that the largest supported BTN_TOOL_*TAP event is larger than the
93 ------------------
95 Here is what a minimal event sequence for a two-contact touch would look
123 ABS_MT events, the last SYN_MT_REPORT event may be omitted. Otherwise, the
125 zero-contact event reaching userland.
129 ------------------
131 Here is what a minimal event sequence for a two-contact touch would look
152 ABS_MT_TRACKING_ID -1
162 ABS_MT_TRACKING_ID -1
166 Event Usage
167 -----------
186 than unity, is related to the contact pressure. For pressure-based devices,
217 direction of the finger ellipse is given by the vector (a - b).
223 finger or a pen or something else. Finally, the ABS_MT_TRACKING_ID event
231 Event Semantics
232 ---------------
241 contact is circular, this event can be omitted [#f4]_.
260 of TOUCH and WIDTH for pressure-based devices or any device with a spatial
264 If the resolution is non-zero, the pressure data is in units/gram. See
265 :ref:`input-event-codes` for details.
280 direction, the range -max should be returned.
284 indicate more than a quarter of a revolution. For an upside-down finger,
317 event should be omitted. The protocol currently mainly supports
319 For type B devices, this event is handled by input core; drivers should
327 the contact. This is a low-level anonymous grouping for type A devices, and
328 should not be confused with the high-level trackingID [#f5]_. Most type A
329 devices do not have blob capability, so drivers can safely omit this event.
335 time. For type B devices, this event is handled by input core; drivers
339 Event Computation
340 -----------------
378 ellipse should align with the vector (T - C), so the diameter must
383 ---------------
387 problem. At each event synchronization, the set of actual contacts is
393 --------
403 -----
406 in a finger packet must not be recognized as single-touch events.
411 .. [#f1] Also, the difference (TOOL_X - POSITION_X) can be used to model tilt.
414 .. [#f4] See the section on event computation.