[PATCH libinput] touchpad: only check for vertical finger distribution on 2fg gestures

[Hans de Goede]

Hi,

On 28-06-16 08:22, Peter Hutterer wrote:
> A natural hand position for a 4-finger swipe will have one finger well below
> the other triggering the pinch detection. This is obviously wrong, only do the
> finger position analysis when we have 2 fingers.
>
> This is only a partial fix, for 3-4 finger gestures chances are high that the
> third/fourth finger come in a different event frame. Before that we likely
> detect 2 fingers in a possible pinch position and still trigger the code path.
> This issue has to be fixed separately.
>
> https://bugs.freedesktop.org/show_bug.cgi?id=96687
>
> Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>

Patch looks good to me:

Reviewed-by: Hans de Goede <hdegoede at redhat.com>

Regards,

Hans


> ---
>  src/evdev-mt-touchpad-gestures.c | 25 +++++++++++++------------
>  1 file changed, 13 insertions(+), 12 deletions(-)
>
> diff --git a/src/evdev-mt-touchpad-gestures.c b/src/evdev-mt-touchpad-gestures.c
> index a8ff37e..e4e465a 100644
> --- a/src/evdev-mt-touchpad-gestures.c
> +++ b/src/evdev-mt-touchpad-gestures.c
> @@ -330,19 +330,20 @@ tp_gesture_handle_state_unknown(struct tp_dispatch *tp, uint64_t time)
>
>  	/* for two-finger gestures, if the fingers stay unmoving for a
>  	 * while, assume (slow) scroll */
> -	if (tp->gesture.finger_count == 2 &&
> -	    time > (tp->gesture.initial_time + DEFAULT_GESTURE_2FG_SCROLL_TIMEOUT)) {
> -		tp_gesture_set_scroll_buildup(tp);
> -		return GESTURE_STATE_SCROLL;
> -	}
> +	if (tp->gesture.finger_count == 2) {
> +		if (time > (tp->gesture.initial_time + DEFAULT_GESTURE_2FG_SCROLL_TIMEOUT)) {
> +			tp_gesture_set_scroll_buildup(tp);
> +			return GESTURE_STATE_SCROLL;
> +		}
>
> -	/* Else check if one finger is > 20mm below the others */
> -	vert_distance = abs(first->point.y - second->point.y);
> -	if (vert_distance > 20 * yres &&
> -	    tp->gesture.finger_count > 2 &&
> -	    tp->gesture.enabled) {
> -		tp_gesture_init_pinch(tp);
> -		return GESTURE_STATE_PINCH;
> +		/* Else check if one finger is > 20mm below the others */
> +		vert_distance = abs(first->point.y - second->point.y);
> +		if (vert_distance > 20 * yres &&
> +		    tp->gesture.finger_count > 2 &&
> +		    tp->gesture.enabled) {
> +			tp_gesture_init_pinch(tp);
> +			return GESTURE_STATE_PINCH;
> +		}
>  	}
>
>  	/* Else wait for both fingers to have moved */
>