Hi, Some questions below.. On Wed, Apr 6, 2016 at 11:52 PM, Peter Hutterer <[email protected]> wrote:
> On Wed, Apr 06, 2016 at 10:17:35AM -0700, Dennis Kempin wrote: > > On Tue, Apr 5, 2016 at 5:26 PM, Peter Hutterer <[email protected]> > wrote: > > > On Tue, Apr 05, 2016 at 01:09:31PM -0700, Dennis Kempin wrote: > > >> [...] > > >> + </description> > > >> + <arg name="id" type="int" summary="the unique ID of this touch > point"/> > > >> + <arg name="major" type="fixed" summary="length of the major > > >> axis in surface coordinates"/> > > >> + <arg name="minor" type="fixed" summary="length of the minor > > >> axis in surface coordinates"/> > > >> + <arg name="orientation" type="fixed" > > >> + summary="angle between major axis and surface x-axis in > degrees"/> > > >> + </event> > Jumping on the major/minor train. Is there no interest in pressure values? It seems that more accurate touchscreens that may offer reproducible pressure values become mainstream.. > > [...] > > Maybe we could include a fallback event for devices that do not have > > good support? > > One that would only use a single value to describe the size of a > > touch, normalized > > to 0..1. In practice, I do not think we could put any more requirements > on this > > value. There is no way for us to tell how tell if a device is using > > the full range > > (0 to reported max axis value), and in a bad case we might end up with > that > > size being in the range of 0 to 0.1. > > > > Let me know what you think about this. > > I'm mostly thinking about how to enable this in libinput from a technical > perspective, and the obvious solution would be whitelisting or blacklisting > devices, combined with the calibration you use as well. > > the fallback wouldn't be normalized but simply skipping it where we can't > be > sure. to do that, we need to do one thing though: split up the events into > area and orientation as separate events. we can send orientation even when > the area is unknown. > > how does that sound? > Are you referring to libinput events or wayland events here? Why would splitting the events help? I have also seen touchscreens just offering a major axis and an orientation. That is an edge case but even there we could have finger-heuristic to estimate a minor value.. @Dennis: I am curious how complex the contact size calibration function in chrome os is. regards Andreas
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