On Wed, Dec 8, 2010 at 9:43 AM, Chase Douglas <chase.douglas@xxxxxxxxxxxxx> wrote: > On 12/07/2010 03:29 AM, Henrik Rydberg wrote: >> Some touch devices are capable of detecting the envelope or hull >> of the touches, but not the touches themselves. This patch adds >> the MT_TOOL_ENVELOPE touch type to be used for such devices. >> >> Signed-off-by: Henrik Rydberg <rydberg@xxxxxxxxxxx> >> --- >> Hi all, >> >> This patch represents an MT solution for those devices that can detect >> and report some effects of dual touch, but cannot report individual >> contacts. Synaptics and elantech are two examples. Having the drivers >> report the bounding rectangle of the touches is useful in userland, >> since the information makes it possible to implement zooming >> gestures. At the same time, it would be confusing to send these >> envelope points as fingers, since they clearly are not. As a remedy, >> introduce MT_TOOL_ENVELOPE, which tells applications that care about >> details that these are not real fingers, at the same time as it allows >> gesture applications based on MT data to function without >> modification. > > Is it assumed that the envelop has only two touches comprising it? Or is > it any number of touches? If it's any number of touches, how does one > know how many touches it is? Those are good questions. Specifying how many touches are in the envelop makes sense. It also covers rectangle as a special case of envelop. Ping > How are the envelop shape and position determined? > > I think the idea is good, I just don't have enough information to > understand how the tool type is supposed to be used. This has been an > issue with many evdev properties, so I'm hoping we can provide more > detailed documentation this time around :). > > -- Chase > -- > 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 > -- 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
