2010/3/20 Ping Cheng <[email protected]>: > 2010/3/20 Rafi Rubin <[email protected]>: >>>> The reporting is always for the whole group, since the contacts are >>>> interdependent. I do not see what argument stands because of this, nor the >>>> rationale behind it. Could you clarify, please? >>> >>> If we consider to filter the data in the kernel, reporting ID from the >>> kernel is unavoidable. Otherwise we would have to either filter the >>> whole group or report the whole group even if there is only one point >>> in the group changed significantly. >> >> Henrik expressed the assumption that the whole group would be transmitted >> together. I had some thoughts about keeping or not keeping ID, but I have >> another idea. >> >> Why don't we just report delta(ID). > > I might have mistaken the definition of tracking ID here.
After reading the Multi-touch (MT) Protocol again, I think combining ABS_MT_TRACKING_ID with ABS_MT_BLOB_ID resolves my ID issue. So, I withdraw my support to add a software tracking ID in the kernel. I think ABS_MT_BLOB_ID serves as the software tracking ID, if I don't misunderstand the use of ABS_MT_BLOB_ID here. But, I reserve the request for a contact count in the kernel until I understand the definition of "the whole group". Henrik, by "the whole group", do you mean: 1. all the contacts/fingers on the screen/surface at a certain time, or 2. all the touch points supported by the hardware, or 3. all the contacts defined in a blob? If it is case 1, it would be nice if we (X driver or contact driver in your term :) know the total contacts the hardware support (if there is a limit) and how many contacts we are getting; if it is case 2, it would be nice if we know the total touches. Reporting it only once in the kernel would be enough since it would be a constant during its life time (my concern is we would need to repeat the unchanged touches in this case); if it is case 3, I think we could consider each blob as an finger/touch group. Then reporting the number of blob/fingers as well as number of contacts in the blob would make sense too. The Multi-touch (MT) Protocol might have already provided everything I need. But I have to understand it to use it appropriately. Thank you, Henrik. Ping _______________________________________________ [email protected]: X.Org development Archives: http://lists.x.org/archives/xorg-devel Info: http://lists.x.org/mailman/listinfo/xorg-devel
