Fix coasting friction

As a result of commit 5a1612d4496b51682c9043aa064025c545249de6, coasting speed
was bumped up to a different scale by removing the divisor during the
calculation of initial coasting speed. This caused coasting friction to have
little to no effect, resulting in coasting that lasted virtually forever using
the default coasting friction value of 50.

This patch multiplies the scroll_dist_{horiz,vert} which was previously used as
a divisor for initial coasting speed to the coasting friction before deducting
it at each step, thus bringing coasting friction back under control.

Signed-off-by: Chow Loong Jin <hyperair@debian.org>
Tested-by: <Magnus.Kessler@gmx.net>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

1 files changed, 2 insertions, 2 deletions

diff --git a/src/synaptics.c b/src/synaptics.c
index 2ea7375..350567d 100644
--- a/src/synaptics.c
+++ b/src/synaptics.c
@@ -2587,7 +2587,7 @@ HandleScrolling(SynapticsPrivate *priv, struct SynapticsHwState *hw,
 
     if (priv->scroll.coast_speed_y) {
         double dtime = (hw->millis - priv->scroll.last_millis) / 1000.0;
-        double ddy = para->coasting_friction * dtime;
+        double ddy = para->coasting_friction * dtime * para->scroll_dist_vert;
         priv->scroll.delta_y += priv->scroll.coast_speed_y * dtime;
         delay = MIN(delay, POLL_MS);
         if (abs(priv->scroll.coast_speed_y) < ddy) {
@@ -2600,7 +2600,7 @@ HandleScrolling(SynapticsPrivate *priv, struct SynapticsHwState *hw,
 
     if (priv->scroll.coast_speed_x) {
         double dtime = (hw->millis - priv->scroll.last_millis) / 1000.0;
-        double ddx = para->coasting_friction * dtime;
+        double ddx = para->coasting_friction * dtime * para->scroll_dist_horiz;
         priv->scroll.delta_x += priv->scroll.coast_speed_x * dtime;
         delay = MIN(delay, POLL_MS);
         if (abs(priv->scroll.coast_speed_x) < ddx) {