Added "friction physics" so coasting can stop on its own.

When you are coasting (but not corner coasting) you might want the
scrolling to slow down and stop on its own.  This also lets you
start coasting while using a two finger scroll.

Signed-off-by: Patrick Curran <pjcurran@wisc.edu>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Tested-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

1 files changed, 7 insertions, 6 deletions

diff --git a/src/properties.c b/src/properties.c
index b17089c..ee9a5a6 100644
--- a/src/properties.c
+++ b/src/properties.c
@@ -243,7 +243,8 @@ InitDeviceProperties(LocalDevicePtr local)
     prop_palm_dim = InitAtom(local->dev, SYNAPTICS_PROP_PALM_DIMENSIONS, 32, 2, values);
 
     fvalues[0] = para->coasting_speed;
-    prop_coastspeed = InitFloatAtom(local->dev, SYNAPTICS_PROP_COASTING_SPEED, 1, fvalues);
+    fvalues[1] = para->coasting_friction;
+    prop_coastspeed = InitFloatAtom(local->dev, SYNAPTICS_PROP_COASTING_SPEED, 2, fvalues);
 
     values[0] = para->press_motion_min_z;
     values[1] = para->press_motion_max_z;
@@ -600,14 +601,14 @@ SetProperty(DeviceIntPtr dev, Atom property, XIPropertyValuePtr prop,
         para->palm_min_z     = dim[1];
     } else if (property == prop_coastspeed)
     {
-        float speed;
+        float *coast_speeds;
 
-        if (prop->size != 1 || prop->format != 32 || prop->type != float_type)
+        if (prop->size != 2 || prop->format != 32 || prop->type != float_type)
             return BadMatch;
 
-        speed = *(float*)prop->data;
-        para->coasting_speed = speed;
-
+        coast_speeds = (float*)prop->data;
+        para->coasting_speed = coast_speeds[0];
+        para->coasting_friction = coast_speeds[1];
     } else if (property == prop_pressuremotion)
     {
         float *press;