[PATCH libinput 11/11] touchpad: put a movement threshold on thumb detection

[Hans de Goede]

Hi,

On 23-07-15 04:31, Peter Hutterer wrote:
> On Wed, Jul 22, 2015 at 03:54:02PM +0200, Hans de Goede wrote:
>> Hi,
>>
>> On 22-07-15 07:09, Peter Hutterer wrote:
>>> If a thumb moves around, it's not resting and we should consider it a normal
>>> touch.
>>>
>>> Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
>>> ---
>>>   src/evdev-mt-touchpad.c | 16 ++++++++++++++++
>>>   src/evdev-mt-touchpad.h |  1 +
>>>   test/touchpad.c         | 31 ++++++++++++++++++++++++++++---
>>>   3 files changed, 45 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/src/evdev-mt-touchpad.c b/src/evdev-mt-touchpad.c
>>> index 0b39bf6..63ce488 100644
>>> --- a/src/evdev-mt-touchpad.c
>>> +++ b/src/evdev-mt-touchpad.c
>>> @@ -636,6 +636,22 @@ tp_thumb_detect(struct tp_dispatch *tp, struct tp_touch *t, uint64_t time)
>>>   		goto out;
>>>   	}
>>>
>>> +	/* If the thumb moves by more than 7mm, it's not a resting thumb */
>>> +	if (t->state == TOUCH_BEGIN)
>>> +		t->thumb.initial = t->point;
>>> +	else if (t->state == TOUCH_UPDATE) {
>>> +		struct device_float_coords delta;
>>> +		struct normalized_coords normalized;
>>> +
>>> +		delta = device_delta(t->point, t->thumb.initial);
>>> +		normalized = tp_normalize_delta(tp, delta);
>>> +		if (normalized_length(normalized) >
>>> +			TP_MM_TO_DPI_NORMALIZED(7)) {
>>> +			t->thumb.state = THUMB_STATE_NO;
>>> +			goto out;
>>> +		}
>>> +	}
>>> +
>>>   	/* Note: a thumb at the edge of the touchpad won't trigger the
>>>   	 * threshold, the surface area is usually too small. So we have a
>>>   	 * two-stage detection: pressure and time within the area.
>>
>> If you want this to mark thouches with THUMB_STATE_YES as THUMB_STATE_NO
>> this needs to be above the:
>>
>>      /* once a thumb, always a thumb, once ruled out always ruled out */
>>      if (!tp->thumb.detect_thumbs ||
>>          t->thumb.state != THUMB_STATE_MAYBE)
>>           return;
>>
>> Block, and maybe the commentline above the if() of that block needs to
>> be updated too ...
>
> see my comment to the other patch, for now I'd like to leave it as "once a
> thumb, always a thumb".

Ok.

>> Also does this commit not require updates to the svg with the thumb detect
>> statemachine ?
>
> the svg in the other patch is a graphic for the documentation page, not a
> state diagram. the state machine is simple enough (and constrained to a
> single function) that I didn't bother with a state diagram.

Ah, ok. In that case:

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

For both patch 7 and 11 (this one).

Regards,

Hans