accel_profile_smooth_simple: Stretch alternative 1

Signed-off-by: Hans de Goede <hdegoede@redhat.com>

1 files changed, 11 insertions, 5 deletions

diff --git a/src/filter.c b/src/filter.c
index ed965ff..991f6aa 100644
--- a/src/filter.c
+++ b/src/filter.c
@@ -397,8 +397,8 @@ pointer_accel_profile_smooth_simple(struct motion_filter *filter,
 	double threshold = accel_filter->threshold;
 	double accel = accel_filter->accel;
 	double smooth_accel_coefficient;
-	/* Increasing this makes reaching max accel take longer */
-	const double stretch = 2.0;
+	/* Increasing this makes reaching max accel take longer (min 1.0) */
+	const double stretch = 3.0;
 
 	if (threshold < 1.0)
 		threshold = 1.0;
@@ -414,11 +414,17 @@ pointer_accel_profile_smooth_simple(struct motion_filter *filter,
 		return 1.0;
 
 	velocity /= threshold;
-	if (velocity >= (accel * stretch))
+	if (velocity < accel) {
+		/* Velocity is 1.0 - accel, scale this to 0.0 - 0.5 */
+		velocity = 0.5 * (velocity - 1.0) / (accel - 1.0);
+	} else if (velocity < (accel * stretch)) { 
+		/* Velocity is accel - (accel * stretch),
+		   scale this to 0.5 - 1.0 */
+		velocity = 0.5 + 0.5 *
+				(velocity - accel) / (accel * (stretch - 1.0));
+	} else
 		return accel;
 
-	/* Velocity is 1.0 - (accel * stretch), scale this to 0.0 - 1.0 */
-	velocity = (velocity - 1.0) / (accel * stretch - 1.0);
 	smooth_accel_coefficient = calc_penumbral_gradient(velocity);
 	return 1.0 + (smooth_accel_coefficient * (accel - 1.0));
 }