Lines Matching +full:multi +full:- +full:slot
4 Multi-touch (MT) Protocol
7 :Copyright: |copy| 2009-2010 Henrik Rydberg <[email protected]>
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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
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34 packet. Since these events are ignored by current single-touch (ST)
44 input_mt_slot(), with a slot as argument, at the beginning of each packet.
46 prepare for updates of the given slot.
48 All drivers mark the end of a multi-touch transfer by calling the usual
54 type B slot protocol lies in the usage of identifiable contacts to reduce
55 the amount of data sent to userspace. The slot protocol requires the use of
64 For type B devices, the kernel driver should associate a slot with each
65 identified contact, and use that slot to propagate changes for the contact.
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
73 attribute of the current slot.
76 driver. A driver for such a device should associate one type B slot with each
78 contact associated with a slot changes, the driver should invalidate that
79 slot by changing its ABS_MT_TRACKING_ID. If the hardware signals that it is
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95 Here is what a minimal event sequence for a two-contact touch would look
125 zero-contact event reaching userland.
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131 Here is what a minimal event sequence for a two-contact touch would look
150 Here is the sequence after lifting the contact in slot 0::
152 ABS_MT_TRACKING_ID -1
155 The slot being modified is already 0, so the ABS_MT_SLOT is omitted. The
156 message removes the association of slot 0 with contact 45, thereby
157 destroying contact 45 and freeing slot 0 to be reused for another contact.
162 ABS_MT_TRACKING_ID -1
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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).
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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,
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
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378 ellipse should align with the vector (T - C), so the diameter must
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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.