-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 05/19/10 20:13, Ping Cheng wrote: > On Wed, May 19, 2010 at 4:34 PM, Rafi Rubin <rafi@xxxxxxxxxxxxxx> wrote: >> My understanding is that it would be more like >> + SYN_MT_SLOT 0 >> + ABS_MT_POSITION_X x >> + ABS_MT_POSITION_Y y >> + SYN_REPORT >> + SYN_MT_SLOT 0 >> + ABS_MT_POSITION_X x >> + ABS_MT_POSITION_Y y >> + SYN_REPORT >> + SYN_MT_SLOT 0 >> + ABS_MT_POSITION_X x >> + ABS_MT_POSITION_Y y >> + SYN_MT_SLOT 1 >> + ABS_MT_POSITION_X x >> + ABS_MT_POSITION_Y y >> + SYN_REPORT > > You are right if one slot only has or is only allowed to have one > point. My scenario is that one slot can have more than one point. > Basically, my intention is to utilize the MT_SLOT and MT_TRACKING_ID > in such a way that it avoids as much overlap as possible. > > And hopefully it makes sesne in the reality too. Please clarify by what you mean by more than one point. I may be misunderstanding, but I thought that these slots are basically a superior replacement to tracking id. one finger -> one slot But with slots we can use the filtering that input provides, which we've been by-passing with the existing MT protocol (at least that's what I think Henrik's goal is). Rafi >> (2 events from 1 finger, followed by 1 event with both). >> >> >> On 05/19/2010 06:43 PM, Ping Cheng wrote: >>> >>> Hi Henrik, >>> >>> I am trying to link the protocol to the actual multi-touch devices in >>> my "mind". Hope it helps you to point out the mismatch between my >>> imagination and the protocol. Please see details in line. >>> >>> Ping >>> >>> On Tue, May 18, 2010 at 1:10 PM, Henrik Rydberg<rydberg@xxxxxxxxxxx> >>> wrote: >>>> >>>> This patch adds documentation for the SYN_MT_SLOT event and >>>> gives examples of how to use the event slot protocol. >>> >>> Am I right in thinking that SYN_MT_SLOT represents to the actual touch >>> area/finger on the surface? There could be more than one (x,y) (a few >>> points that form an irregular shape) that represents one finger. The >>> following example shows that slot 0 (finger 1) touched three points on >>> the surface while slot 1 (finger 2) only has one point reported: >>> >>> + SYN_MT_SLOT 0 >>> + ABS_MT_TRACKING_ID 45 >>> + ABS_MT_POSITION_X x[0] >>> + ABS_MT_POSITION_Y y[0] >>> + ABS_MT_TRACKING_ID 46 >>> + ABS_MT_POSITION_X x[1] >>> + ABS_MT_POSITION_Y y[1] >>> + ABS_MT_TRACKING_ID 47 >>> + ABS_MT_POSITION_X x[2] >>> + ABS_MT_POSITION_Y y[2] >>> + SYN_MT_SLOT 1 >>> + ABS_MT_TRACKING_ID 30 >>> + ABS_MT_POSITION_X x[3] >>> + ABS_MT_POSITION_Y y[3] >>> + SYN_REPORT >>> >>> If my assumption is correct, i.e., one slot can have more than one >>> point, I would think ABS_MT_TRACKING_ID may not have to be a required >>> entry inside SYN_MT_SLOT. To the user land clients/drivers, >>> SYN_MT_SLOT itself could serve as an ID. So, the following case is >>> also a type B ( we know there are two touch areas. But we don't keep >>> track of the points inside the areas): >>> >>> + SYN_MT_SLOT 0 >>> + ABS_MT_POSITION_X x[0] >>> + ABS_MT_POSITION_Y y[0] >>> + ABS_MT_POSITION_X x[1] >>> + ABS_MT_POSITION_Y y[1] >>> + ABS_MT_POSITION_X x[2] >>> + ABS_MT_POSITION_Y y[2] >>> + SYN_MT_SLOT 1 >>> + ABS_MT_POSITION_X x[3] >>> + ABS_MT_POSITION_Y y[3] >>> + SYN_REPORT >>> >>> So, an EVIO for X driver to retrieve the number of SLOTs would be very >>> helpful. Something like the following would do the work: >>> >>> input_set_abs_params(input_dev, ABS_MT_SLOT, 0, 12, 0, 0); >>> >>> which tells the user land clients that they can expect up to 13 touch >>> areas. >>> >>>> +The main difference between the raw type A protocol and the higher level >>>> +type B slot protocol lies in the usage of identifiable contacts. The >>>> slot >>>> +protocol requires the use of the ABS_MT_TRACKING_ID, >>> >>> With what I said above, I think ABS_MT_TRACKING_ID is not the unique >>> identifier for type B protocol. It is the fact that we can identify >>> individual touch areas and use ABS_MT_SLOT to report them that makes >>> it a type B event. >>> >>>> ABS_MT_TRACKING_ID, either provided by the >>>> +hardware of computed from the raw data [5]. >>> >>> ^^ or (is it?) >>> >>> I agree with this ABS_MT_TRACKING_ID definition. I would think something >>> like: >>> >>> input_set_abs_params(input_dev, ABS_MT_TRACKING_ID, 0, 47, 0, 0); >>> >>> which tells the clients that total of 48 points are tracked, would be >>> helpful. >>> >>> Another topic that may be irrelevant to this patch is the filter. With >>> the use of ABS_MT_TRACKING_ID, a filter can be applied to discard the >>> useless repeated points or less than a certain number of points >>> movement. >>> >> > -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkv0gZgACgkQwuRiAT9o60/v5QCguYH/eGD4R12cIPGc/AF3Xz6Y RXgAoIfEYSVqekbLRU4NXHo0bnG323vA =OUmf -----END PGP SIGNATURE----- -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
