[PATCH weston 16/25] libweston: introduce notify_touch_cal() and doc

[Pekka Paalanen]

On Mon, 9 Apr 2018 12:12:49 +1000
Peter Hutterer <peter.hutterer at who-t.net> wrote:

> On Fri, Mar 23, 2018 at 02:00:56PM +0200, Pekka Paalanen wrote:
> > From: Pekka Paalanen <pekka.paalanen at collabora.co.uk>
> > 
> > notify_touch_cal() is an extended form of notify_touch(), adding
> > normalized touch coordinates which are necessary for calibrating a
> > touchscreen.
> > 
> > It would be possible to invert the transformation and convert from
> > global coordinates to normalized device coordinates in input.c without
> > adding this API, but this way it is more robust against code changes.
> > 
> > Recovering normalized device coordinates is necessary because libinput
> > calibration matrix must be given in normalized units, and it would be
> > difficult to compute otherwise. Libinput API does not offer normalized
> > coordinates directly either, but those can be fetched by pretending the
> > output resolution is 1x1.
> > 
> > Anticipating touch calibration mode, the old notify_touch() is renamed
> > into a private process_touch_normal(), and the new notify_touch_cal()
> > delegates to it.
> > 
> > Co-developed by Louis-Francis and Pekka.
> > 
> > Cc: Louis-Francis Ratté-Boulianne <lfrb at collabora.com>
> > Signed-off-by: Pekka Paalanen <pekka.paalanen at collabora.co.uk>
> > ---
> >  libweston/compositor.h      | 21 +++++++++++++++-
> >  libweston/input.c           | 60 ++++++++++++++++++++++++++++++++++++---------
> >  libweston/libinput-device.c | 11 ++++++++-
> >  3 files changed, 79 insertions(+), 13 deletions(-)

> > --- a/libweston/input.c
> > +++ b/libweston/input.c
> > @@ -2336,17 +2336,10 @@ weston_touch_set_focus(struct weston_touch *touch, struct weston_view *view)
> >  	touch->focus = view;
> >  }
> >  
> > -/**
> > - * notify_touch - emulates button touches and notifies surfaces accordingly.
> > - *
> > - * It assumes always the correct cycle sequence until it gets here: touch_down
> > - * → touch_update → ... → touch_update → touch_end. The driver is responsible
> > - * for sending along such order.
> > - *
> > - */
> > -WL_EXPORT void
> > -notify_touch(struct weston_touch_device *device, const struct timespec *time,
> > -	     int touch_id, double double_x, double double_y, int touch_type)
> > +static void
> > +process_touch_normal(struct weston_touch_device *device,
> > +		     const struct timespec *time, int touch_id,
> > +		     double double_x, double double_y, int touch_type)  
> 
> IMO just process_touch() is better, otherwise it's more confusing ("wait?
> why is this normal? and what's not normal? or is this an abbreviation of
> normalized?")

Actually, this is really the normal path. The not normal path is the
one for calibrator. You see the non-normal path added in "input:
introduce touch event mode for calibrator".

I didn't want to call it process_touch() originally, because it doesn't
process all touches, just the usual case. I even call it
WESTON_TOUCH_MODE_NORMAL.

Would you have other suggestions?


Thanks,
pq
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