[PATCH libinput 11/20] touchpad: Rework is_pointer handling

[Peter Hutterer]

On Tue, Apr 15, 2014 at 02:28:08PM +0200, Hans de Goede wrote:
> Move scanning for a suitable touch to be the pointer to tp_process_state
> and take tp_button_touch_active into account.
> 
> Note this adds a tp_touch_active helper since we want to do the same checks in
> other places too (ie to see if a finger should count for 2 finger scrolling).
> 
> Signed-off-by: Hans de Goede <hdegoede at redhat.com>
> Acked-by: Peter Hutterer <peter.hutterer at who-t.net>
> ---
>  src/evdev-mt-touchpad.c | 47 +++++++++++++++++++++++------------------------
>  1 file changed, 23 insertions(+), 24 deletions(-)
> 
> diff --git a/src/evdev-mt-touchpad.c b/src/evdev-mt-touchpad.c
> index 9df4a78..b671211 100644
> --- a/src/evdev-mt-touchpad.c
> +++ b/src/evdev-mt-touchpad.c
> @@ -152,8 +152,6 @@ tp_get_touch(struct tp_dispatch *tp, unsigned int slot)
>  static inline void
>  tp_begin_touch(struct tp_dispatch *tp, struct tp_touch *t)
>  {
> -	struct tp_touch *tmp;
> -
>  	if (t->state != TOUCH_UPDATE) {
>  		tp_motion_history_reset(t);
>  		t->dirty = true;
> @@ -161,15 +159,6 @@ tp_begin_touch(struct tp_dispatch *tp, struct tp_touch *t)
>  		tp->nfingers_down++;
>  		assert(tp->nfingers_down >= 1);
>  		tp->queued |= TOUCHPAD_EVENT_MOTION;
> -
> -		tp_for_each_touch(tp, tmp) {
> -			if (tmp->is_pointer)
> -				break;
> -		}
> -
> -		if (!tmp->is_pointer) {
> -			t->is_pointer = true;
> -		}
>  	}
>  }
>  
> @@ -341,7 +330,6 @@ static void
>  tp_unpin_finger(struct tp_dispatch *tp, struct tp_touch *t)
>  {
>  	unsigned int xdist, ydist;
> -	struct tp_touch *tmp;
>  
>  	if (!t->pinned.is_pinned)
>  		return;
> @@ -349,19 +337,9 @@ tp_unpin_finger(struct tp_dispatch *tp, struct tp_touch *t)
>  	xdist = abs(t->x - t->pinned.center_x);
>  	ydist = abs(t->y - t->pinned.center_y);
>  
> -	if (xdist * xdist + ydist * ydist <
> +	if (xdist * xdist + ydist * ydist >=
>  			tp->buttons.motion_dist * tp->buttons.motion_dist)
> -		return;
> -
> -	t->pinned.is_pinned = false;
> -
> -	tp_for_each_touch(tp, tmp) {
> -		if (tmp->is_pointer)
> -			break;
> -	}
> -
> -	if (t->state != TOUCH_END && !tmp->is_pointer)
> -		t->is_pointer = true;
> +		t->pinned.is_pinned = false;
>  }
>  
>  static void
> @@ -377,6 +355,13 @@ tp_pin_fingers(struct tp_dispatch *tp)
>  	}
>  }
>  
> +static int
> +tp_touch_active(struct tp_dispatch *tp, struct tp_touch *t)
> +{
> +	return (t->state == TOUCH_BEGIN || t->state == TOUCH_UPDATE) &&
> +		!t->pinned.is_pinned && tp_button_touch_active(tp, t);
> +}
> +
>  static void
>  tp_process_state(struct tp_dispatch *tp, uint32_t time)
>  {
> @@ -409,6 +394,20 @@ tp_process_state(struct tp_dispatch *tp, uint32_t time)
>  	if ((tp->queued & TOUCHPAD_EVENT_BUTTON_PRESS) &&
>  	    !tp->buttons.has_buttons)
>  		tp_pin_fingers(tp);
> +
> +	/* If we don't have a touch as pointer find a suitable one */
> +	tp_for_each_touch(tp, t) {
> +		if (t->is_pointer)
> +			break;
> +	}
> +	if (!t->is_pointer) {
> +		tp_for_each_touch(tp, t) {
> +			if (tp_touch_active(tp, t)) {
> +				t->is_pointer = true;
> +				break;
> +			}
> +		}
> +	}
>  }
>  

this changes the way the touchpad behaves for scrolling (it breaks the
touchpad_2fg_no_motion test). Before, a touch is marked as pointer touch on
begin. Now a touch can be marked pointer touch as soon as it is the last
touch and that causes a spurious motion event in the above test: as soon as
the first finger is lifted, the second finger generates a motion event.

This is a bit of a side-effect pinning all fingers, I think we need
something more sophisticated to tell which touchpoint is the controlling
one.

Cheers,
   Peter