Attachment 115255 Details for Bug 90086 – 0001-filter-enforce-minimum-velocity.patch

[patch] 0001-filter-enforce-minimum-velocity.patch

0001-filter-enforce-minimum-velocity.patch (text/plain), 2.55 KB, created by Peter Hutterer on 2015-04-22 02:33:31 UTC

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Creator: Peter Hutterer

Created: 2015-04-22 02:33:31 UTC

Size: 2.55 KB

patch

obsolete

>From 6a97e545fbc53d63813df7fa7e436a7083e19c2f Mon Sep 17 00:00:00 2001
>From: Peter Hutterer <peter.hutterer@who-t.net>
>Date: Wed, 22 Apr 2015 12:25:13 +1000
>Subject: [PATCH libinput] filter: enforce minimum velocity
>
>In the current code, a timeout or direction change on the first tracker will
>result in a velocity of 0. Really slow movements will thus always be zero, and
>the first event after a direction is swallowed.
>
>Enforce a minimum velocity:
>In the case of a timeout, assume the current velocity is that of
>distance/timeout. In the case of a direction change, the velocity is simply
>that since the last tracker.
>
>Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
>---
> src/filter.c | 34 ++++++++++++++++++++++++++++++----
> 1 file changed, 30 insertions(+), 4 deletions(-)
>
>diff --git a/src/filter.c b/src/filter.c
>index b446221..e9aaf7b 100644
>--- a/src/filter.c
>+++ b/src/filter.c
>@@ -142,6 +142,24 @@ calculate_tracker_velocity(struct pointer_tracker *tracker, uint64_t time)
> 	return normalized_length(tracker->delta) / tdelta; /* units/ms */
> }
> 
>+static inline double
>+calculate_velocity_after_timeout(struct pointer_tracker *tracker)
>+{
>+	/* First movement after timeout needs special handling.
>+	 *
>+	 * When we trigger the timeout, the last event is too far in the
>+	 * past to use it for velocity calculation across multiple tracker
>+	 * values.
>+	 *
>+	 * Use the motion timeout itself to calculate the speed rather than
>+	 * the last tracker time. This errs on the side of being too fast
>+	 * for really slow movements but provides much more useful initial
>+	 * movement in normal use-cases (pause, move, pause, move)
>+	 */
>+	return calculate_tracker_velocity(tracker,
>+					  tracker->time + MOTION_TIMEOUT);
>+}
>+
> static double
> calculate_velocity(struct pointer_accelerator *accel, uint64_t time)
> {
>@@ -161,15 +179,23 @@ calculate_velocity(struct pointer_accelerator *accel, uint64_t time)
> 
> 		/* Stop if too far away in time */
> 		if (time - tracker->time > MOTION_TIMEOUT ||
>-		    tracker->time > time)
>+		    tracker->time > time) {
>+			if (offset == 1)
>+				result = calculate_velocity_after_timeout(tracker);
> 			break;
>+		}
>+
>+		velocity = calculate_tracker_velocity(tracker, time);
> 
> 		/* Stop if direction changed */
> 		dir &= tracker->dir;
>-		if (dir == 0)
>+		if (dir == 0) {
>+			/* First movement after dirchange - velocity is that
>+			 * of the last movement */
>+			if (offset == 1)
>+				result = velocity;
> 			break;
>-
>-		velocity = calculate_tracker_velocity(tracker, time);
>+		}
> 
> 		if (initial_velocity == 0.0) {
> 			result = initial_velocity = velocity;
>-- 
>2.3.5
>

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