[PATCH libinput 2/6] touchpad: Fix sending of scroll stop events

[Jonas Ådahl]

On Fri, May 23, 2014 at 04:06:23PM +0200, Hans de Goede wrote:
> Setting tp->scroll.direction = 0 before checking tp->scroll.direction
> to see if we need to send stop scroll events for vert / horz scrolling does
> not really work well.
> 
> Also we need to check direction with an axis mask, not the axis number.
> 
> While at it also add a tp_stop_scroll_events() helper function for this.
> 
> Signed-off-by: Hans de Goede <hdegoede at redhat.com>
> ---
>  src/evdev-mt-touchpad.c | 39 +++++++++++++++++++++++----------------
>  1 file changed, 23 insertions(+), 16 deletions(-)
> 
> diff --git a/src/evdev-mt-touchpad.c b/src/evdev-mt-touchpad.c
> index 040939b..2455c36 100644
> --- a/src/evdev-mt-touchpad.c
> +++ b/src/evdev-mt-touchpad.c
> @@ -500,6 +500,28 @@ tp_post_twofinger_scroll(struct tp_dispatch *tp, uint64_t time)
>  	}
>  }
>  
> +static void
> +tp_stop_scroll_events(struct tp_dispatch *tp, uint64_t time)
> +{
> +	if (tp->scroll.state == SCROLL_STATE_NONE)
> +		return;
> +
> +	/* terminate scrolling with a zero scroll event */
> +	if (tp->scroll.direction & (1 << LIBINPUT_POINTER_AXIS_VERTICAL_SCROLL))
> +		pointer_notify_axis(&tp->device->base,
> +				    time,
> +				    LIBINPUT_POINTER_AXIS_VERTICAL_SCROLL,
> +				    0);
> +	if (tp->scroll.direction & (1 << LIBINPUT_POINTER_AXIS_HORIZONTAL_SCROLL))
> +		pointer_notify_axis(&tp->device->base,
> +				    time,
> +				    LIBINPUT_POINTER_AXIS_HORIZONTAL_SCROLL,
> +				    0);

I can see that you didn't introduce sending 0-valued axis events in this
patch, but why do we do so? weston will ignore it anyway, and if it
wouldn't or other compositor wouldn't, it might confuse clients assuming
that a scroll event will always have a direction.

Jonas

> +
> +	tp->scroll.state = SCROLL_STATE_NONE;
> +	tp->scroll.direction = 0;
> +}
> +
>  static int
>  tp_post_scroll_events(struct tp_dispatch *tp, uint64_t time)
>  {
> @@ -513,22 +535,7 @@ tp_post_scroll_events(struct tp_dispatch *tp, uint64_t time)
>  	}
>  
>  	if (nfingers_down != 2) {
> -		/* terminate scrolling with a zero scroll event to notify
> -		 * caller that it really ended now */
> -		if (tp->scroll.state != SCROLL_STATE_NONE) {
> -			tp->scroll.state = SCROLL_STATE_NONE;
> -			tp->scroll.direction = 0;
> -			if (tp->scroll.direction & LIBINPUT_POINTER_AXIS_VERTICAL_SCROLL)
> -				pointer_notify_axis(&tp->device->base,
> -						    time,
> -						    LIBINPUT_POINTER_AXIS_VERTICAL_SCROLL,
> -						    0);
> -			if (tp->scroll.direction & LIBINPUT_POINTER_AXIS_HORIZONTAL_SCROLL)
> -				pointer_notify_axis(&tp->device->base,
> -						    time,
> -						    LIBINPUT_POINTER_AXIS_HORIZONTAL_SCROLL,
> -						    0);
> -		}
> +		tp_stop_scroll_events(tp, time);
>  	} else {
>  		tp_post_twofinger_scroll(tp, time);
>  		return 1;
> -- 
> 1.9.3
> 
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