[PATCH libinput 09/13] filter: work the touchpad magic slowdown into the various parameters

[Peter Hutterer]

We have everything separate from the mouse now, so having a magic slowdown
isn't needed, we can work this into our parameters. So the acceleration
function now uses everything adjusted, but the factor is still multiplied by
the slowdown in the end.

Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
 src/filter.c | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/src/filter.c b/src/filter.c
index f4baa99..7865c7e 100644
--- a/src/filter.c
+++ b/src/filter.c
@@ -135,10 +135,10 @@ filter_get_type(struct motion_filter *filter)
 #define DEFAULT_INCLINE 1.1			/* unitless factor */
 
 /* Touchpad acceleration */
-#define TOUCHPAD_DEFAULT_THRESHOLD 15.75	/* mm/s */
-#define TOUCHPAD_MINIMUM_THRESHOLD 7.87		/* mm/s */
+#define TOUCHPAD_DEFAULT_THRESHOLD 40		/* mm/s */
+#define TOUCHPAD_MINIMUM_THRESHOLD 20		/* mm/s */
 #define TOUCHPAD_ACCELERATION 2.0		/* unitless factor */
-#define TOUCHPAD_INCLINE 0.02794		/* unitless factor */
+#define TOUCHPAD_INCLINE 0.011			/* unitless factor */
 
 /* for the Lenovo x230 custom accel. do not touch */
 #define X230_THRESHOLD v_ms2us(0.4)		/* in units/us */
@@ -749,8 +749,6 @@ touchpad_accel_profile_linear(struct motion_filter *filter,
 	/* Convert to mm/s because that's something one can understand */
 	speed_in = v_us2s(speed_in) * 25.4/accel_filter->dpi;
 
-	speed_in *= TP_MAGIC_SLOWDOWN;
-
 	/*
 	   Our acceleration function calculates a factor to accelerate input
 	   deltas with. The function is a double incline with a plateau,
@@ -774,10 +772,10 @@ touchpad_accel_profile_linear(struct motion_filter *filter,
 
 	   for speeds up to the lower threshold, we decelerate, down to 30%
 	   of input speed.
-		   hence 1 = a * 2.756 + 0.3
-		       0.7 = a * 2.756  => a := 0.254
+		   hence 1 = a * 7 + 0.3
+		       0.7 = a * 7  => a := 0.1
 		   deceleration function is thus:
-			y = 0.254x + 0.3
+			y = 0.1x + 0.3
 
 	  Note:
 	  * The minimum threshold is a result of trial-and-error and
@@ -785,9 +783,8 @@ touchpad_accel_profile_linear(struct motion_filter *filter,
 	  * 0.3 is chosen simply because it is above the Nyquist frequency
 	    for subpixel motion within a pixel.
 	*/
-	if (speed_in < 2.756) {
-		const double incline = 0.254;
-		factor = incline * speed_in + 0.3;
+	if (speed_in < 7.0) {
+		factor = 0.1 * speed_in + 0.3;
 	/* up to the threshold, we keep factor 1, i.e. 1:1 movement */
 	} else if (speed_in < threshold) {
 		factor = 1;
-- 
2.9.3