On Tue, May 08, 2012 at 08:40:52PM +0200, Henrik Rydberg wrote: > > > 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. problem I see with "outer position" is that I'd associate it with the top/left position of whatever "outer" is, not with the center of said envelope. that's why I'd argue that "center" should be somewhere in the name. Cheers, Peter -- 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
