[PATCH libinput] touchpad: restart the motion filter on touch begin

[Hans de Goede]

Hi,

On 10-06-15 03:25, Peter Hutterer wrote:
> Our motion filter takes the last couple of vectors to calculate speed,
> provided the direction stays the same and it is within a certain timeout. It
> does not take into account lifting the finger, so the velocity on the first
> event is off.
>
> Real-world impact is mainly on scrolling. Before commit 289e4675
> 	filter: enforce minimum velocity
> the first motion on a scroll was accelerated by a factor of 0 and swallowed.
> After 289e4675 the motion was calculated based on the timeout and a fraction
> of the expected effect. Now the first scroll motion is based on the real
> finger motion since setting the finger down and thus feels a bit more
> responsive.
>
> It also makes a couple of test cases using litest_assert_scroll() work again
> since the miniumum motion is now as expected.
>
> Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>

Looks good to me:

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

Regards,

Hans


> ---
>   src/evdev-mt-touchpad.c |  7 +++++++
>   src/filter-private.h    |  3 +++
>   src/filter.c            | 31 +++++++++++++++++++++++++++++++
>   src/filter.h            |  5 +++++
>   4 files changed, 46 insertions(+)
>
> diff --git a/src/evdev-mt-touchpad.c b/src/evdev-mt-touchpad.c
> index 0154e89..8c28ff7 100644
> --- a/src/evdev-mt-touchpad.c
> +++ b/src/evdev-mt-touchpad.c
> @@ -666,6 +666,7 @@ tp_process_state(struct tp_dispatch *tp, uint64_t time)
>   	struct tp_touch *t;
>   	struct tp_touch *first = tp_get_touch(tp, 0);
>   	unsigned int i;
> +	bool restart_filter = false;
>
>   	tp_process_fake_touches(tp, time);
>   	tp_unhover_touches(tp, time);
> @@ -692,8 +693,14 @@ tp_process_state(struct tp_dispatch *tp, uint64_t time)
>   		tp_motion_history_push(t);
>
>   		tp_unpin_finger(tp, t);
> +
> +		if (t->state == TOUCH_BEGIN)
> +			restart_filter = true;
>   	}
>
> +	if (restart_filter)
> +		filter_restart(tp->device->pointer.filter, tp, time);
> +
>   	tp_button_handle_state(tp, time);
>   	tp_edge_scroll_handle_state(tp, time);
>
> diff --git a/src/filter-private.h b/src/filter-private.h
> index 0e796f1..8a206d6 100644
> --- a/src/filter-private.h
> +++ b/src/filter-private.h
> @@ -32,6 +32,9 @@ struct motion_filter_interface {
>   			   struct motion_filter *filter,
>   			   const struct normalized_coords *unaccelerated,
>   			   void *data, uint64_t time);
> +	void (*restart)(struct motion_filter *filter,
> +			void *data,
> +			uint64_t time);
>   	void (*destroy)(struct motion_filter *filter);
>   	bool (*set_speed)(struct motion_filter *filter,
>   			  double speed);
> diff --git a/src/filter.c b/src/filter.c
> index ed5a184..ee4ce9e 100644
> --- a/src/filter.c
> +++ b/src/filter.c
> @@ -44,6 +44,13 @@ filter_dispatch(struct motion_filter *filter,
>   }
>
>   void
> +filter_restart(struct motion_filter *filter,
> +	       void *data, uint64_t time)
> +{
> +	filter->interface->restart(filter, data, time);
> +}
> +
> +void
>   filter_destroy(struct motion_filter *filter)
>   {
>   	if (!filter)
> @@ -274,6 +281,29 @@ accelerator_filter(struct motion_filter *filter,
>   }
>
>   static void
> +accelerator_restart(struct motion_filter *filter,
> +		    void *data,
> +		    uint64_t time)
> +{
> +	struct pointer_accelerator *accel =
> +		(struct pointer_accelerator *) filter;
> +	unsigned int offset;
> +	struct pointer_tracker *tracker;
> +
> +	for (offset = 1; offset < NUM_POINTER_TRACKERS; offset++) {
> +		tracker = tracker_by_offset(accel, offset);
> +		tracker->time = 0;
> +		tracker->dir = 0;
> +		tracker->delta.x = 0;
> +		tracker->delta.y = 0;
> +	}
> +
> +	tracker = tracker_by_offset(accel, 0);
> +	tracker->time = time;
> +	tracker->dir = UNDEFINED_DIRECTION;
> +}
> +
> +static void
>   accelerator_destroy(struct motion_filter *filter)
>   {
>   	struct pointer_accelerator *accel =
> @@ -309,6 +339,7 @@ accelerator_set_speed(struct motion_filter *filter,
>
>   struct motion_filter_interface accelerator_interface = {
>   	accelerator_filter,
> +	accelerator_restart,
>   	accelerator_destroy,
>   	accelerator_set_speed,
>   };
> diff --git a/src/filter.h b/src/filter.h
> index 16896a4..03f510d 100644
> --- a/src/filter.h
> +++ b/src/filter.h
> @@ -37,6 +37,11 @@ struct normalized_coords
>   filter_dispatch(struct motion_filter *filter,
>   		const struct normalized_coords *unaccelerated,
>   		void *data, uint64_t time);
> +
> +void
> +filter_restart(struct motion_filter *filter,
> +	       void *data, uint64_t time);
> +
>   void
>   filter_destroy(struct motion_filter *filter);
>
>