> > to aid in the discussion, I have shared a drawing of the MT model > > and the (supposed) win8 model. > > > > https://docs.google.com/document/d/1KKu7kqPOsvE9tCmWhdGnmO8tgmN0Cd-Mv_crVaCZueY/view > > having an asciiart version of this in Documentation/ would be quite useful, > IMO Yep, that ought to be possible to arrange. > Insert a paragraph into the actual documentation. I think that's more > helpful than tacking it on (if not quite as nice in a diff) > > "The orientation of the ellipse. The value should describe a signed quarter > of a revolution clockwise around the touch center. The signed value range > is arbitrary, but zero should be returned for a finger aligned along the Y > axis of the surface, a negative value when finger is turned to the left, and > a positive value when finger turned to the right. When completely aligned > with the X axis, the range max should be returned. > > Touch ellipsis are symmetrical by default. For devices capable of true 360 > degree orientation, the reported orientation must exceed the range max to > indicate more than a quarter of a revolution. For an upside-down finger, > range max * 2 should be returned. > > Orientation can be omitted if the touching object is circular, or if the > information is not available in the kernel driver. Partial orientation > support is possible if the device can distinguish between the two axis, but > not (uniquely) any values in between. In such cases, the range of > ABS_MT_ORIENTATION should be [0, 1] [4]." Looks good, will copy that in its entirety. :-) > Not a big fan of reporting values above absmin/absmax, tbh. It means we > can't rely on the axis values and have to special-case it. Plus, there's no > way to detect this before you actually get a value. True, and I am open to other suggestions. However, I think the proposal integrates pretty well with the existing model and is likely to produce reasonable results without userland modifications. > > Looking at the figure, it is clear that the MT model has two centers, > > one for each ellipse. Thus, center is not discriminating > > enough. Perhaps ABS_MT_OUTER_X/Y is more appropriate, then? > > ABS_MT_OUTER_CENTER I appreciate the suggestion, but along two-word combinations, ABS_MT_OUTER_POSITION would integrate better with existing names. Both seem awfully long, though. Thanks for your input! Henrik -- 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
