[PATCH v2 libinput] filter: move the pointer acceleration profiles back to units/ms

Peter Hutterer peter.hutterer at who-t.net
Sun Aug 2 17:27:01 PDT 2015


There is no need here to use ┬Ás since we're just handling speeds/thresholds,
not actual events where a ms granularity can be too high.

Moving back to ms lets us drop a bunch of zeroes that clutter up the code, and
since the acceleration functions are a bit magic anyway, having the various
1000.0 factors in there makes it even less obvious.

Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
Changes to v1:
- switch all velocity code to use units/ms instead of units/us


 src/filter.c           | 50 +++++++++++++++++++++++++-------------------------
 tools/ptraccel-debug.c |  4 ++--
 2 files changed, 27 insertions(+), 27 deletions(-)

diff --git a/src/filter.c b/src/filter.c
index 54ae397..2506ee2 100644
--- a/src/filter.c
+++ b/src/filter.c
@@ -77,7 +77,7 @@ filter_get_speed(struct motion_filter *filter)
  * Default parameters for pointer acceleration profiles.
  */
 
-#define DEFAULT_THRESHOLD 0.0004		/* in units/us */
+#define DEFAULT_THRESHOLD 0.4			/* in units/ms */
 #define DEFAULT_ACCELERATION 2.0		/* unitless factor */
 #define DEFAULT_INCLINE 1.1			/* unitless factor */
 
@@ -85,7 +85,7 @@ filter_get_speed(struct motion_filter *filter)
  * Pointer acceleration filter constants
  */
 
-#define MAX_VELOCITY_DIFF	0.001 /* units/us */
+#define MAX_VELOCITY_DIFF	1 /* units/ms */
 #define MOTION_TIMEOUT		ms2us(1000)
 #define NUM_POINTER_TRACKERS	16
 
@@ -101,14 +101,14 @@ struct pointer_accelerator {
 
 	accel_profile_func_t profile;
 
-	double velocity;	/* units/us */
-	double last_velocity;	/* units/us */
+	double velocity;	/* units/ms */
+	double last_velocity;	/* units/ms */
 	struct normalized_coords last;
 
 	struct pointer_tracker *trackers;
 	int cur_tracker;
 
-	double threshold;	/* units/us */
+	double threshold;	/* units/ms */
 	double accel;		/* unitless factor */
 	double incline;		/* incline of the function */
 
@@ -150,7 +150,7 @@ static double
 calculate_tracker_velocity(struct pointer_tracker *tracker, uint64_t time)
 {
 	double tdelta = time - tracker->time + 1;
-	return normalized_length(tracker->delta) / tdelta; /* units/us */
+	return normalized_length(tracker->delta) / tdelta * 1000.0; /* units/ms */
 }
 
 static inline double
@@ -220,7 +220,7 @@ calculate_velocity(struct pointer_accelerator *accel, uint64_t time)
 		}
 	}
 
-	return result; /* units/us */
+	return result; /* units/ms */
 }
 
 static double
@@ -256,11 +256,11 @@ calculate_acceleration(struct pointer_accelerator *accel,
 static struct normalized_coords
 accelerator_filter(struct motion_filter *filter,
 		   const struct normalized_coords *unaccelerated,
-		   void *data, uint64_t time)
+		   void *data, uint64_t time /* in us */)
 {
 	struct pointer_accelerator *accel =
 		(struct pointer_accelerator *) filter;
-	double velocity; /* units/us */
+	double velocity; /* units/ms */
 	double accel_value; /* unitless factor */
 	struct normalized_coords accelerated;
 	struct normalized_coords unnormalized;
@@ -397,23 +397,23 @@ create_pointer_accelerator_filter(accel_profile_func_t profile,
 double
 pointer_accel_profile_linear_low_dpi(struct motion_filter *filter,
 				     void *data,
-				     double speed_in, /* in device units (units/us) */
-				     uint64_t time)
+				     double speed_in, /* in device units (units/ms) */
+				     uint64_t time /* in us */)
 {
 	struct pointer_accelerator *accel_filter =
 		(struct pointer_accelerator *)filter;
 
 	double s1, s2;
 	double max_accel = accel_filter->accel; /* unitless factor */
-	const double threshold = accel_filter->threshold; /* units/us */
+	const double threshold = accel_filter->threshold; /* units/ms */
 	const double incline = accel_filter->incline;
 	double factor;
 	double dpi_factor = accel_filter->dpi_factor;
 
 	max_accel /= dpi_factor;
 
-	s1 = min(1, 0.3 + speed_in * 10000.0);
-	s2 = 1 + (speed_in * 1000.0 - threshold * dpi_factor * 1000.0) * incline;
+	s1 = min(1, 0.3 + speed_in * 10.0);
+	s2 = 1 + (speed_in - threshold * dpi_factor) * incline;
 
 	factor = min(max_accel, s2 > 1 ? s2 : s1);
 
@@ -424,19 +424,19 @@ double
 pointer_accel_profile_linear(struct motion_filter *filter,
 			     void *data,
 			     double speed_in, /* 1000-dpi normalized */
-			     uint64_t time)
+			     uint64_t time /* in us */)
 {
 	struct pointer_accelerator *accel_filter =
 		(struct pointer_accelerator *)filter;
 
 	double s1, s2;
 	const double max_accel = accel_filter->accel; /* unitless factor */
-	const double threshold = accel_filter->threshold; /* units/us */
+	const double threshold = accel_filter->threshold; /* units/ms */
 	const double incline = accel_filter->incline;
 	double factor;
 
-	s1 = min(1, 0.3 + speed_in * 10 * 1000.0);
-	s2 = 1 + (speed_in * 1000.0 - threshold * 1000.0) * incline;
+	s1 = min(1, 0.3 + speed_in * 10);
+	s2 = 1 + (speed_in - threshold) * incline;
 
 	factor =  min(max_accel, s2 > 1 ? s2 : s1);
 
@@ -445,9 +445,9 @@ pointer_accel_profile_linear(struct motion_filter *filter,
 
 double
 touchpad_accel_profile_linear(struct motion_filter *filter,
-                              void *data,
-                              double speed_in,
-                              uint64_t time)
+			      void *data,
+			      double speed_in,
+			      uint64_t time /* in us */)
 {
 	/* Once normalized, touchpads see the same
 	   acceleration as mice. that is technically correct but
@@ -468,7 +468,7 @@ double
 touchpad_lenovo_x230_accel_profile(struct motion_filter *filter,
 				      void *data,
 				      double speed_in,
-				      uint64_t time)
+				      uint64_t time /* in us */)
 {
 	/* Keep the magic factor from touchpad_accel_profile_linear.  */
 	const double TP_MAGIC_SLOWDOWN = 0.4;
@@ -488,13 +488,13 @@ touchpad_lenovo_x230_accel_profile(struct motion_filter *filter,
 	const double max_accel = accel_filter->accel *
 				  TP_MAGIC_LOW_RES_FACTOR; /* unitless factor */
 	const double threshold = accel_filter->threshold /
-				  TP_MAGIC_LOW_RES_FACTOR; /* units/us */
+				  TP_MAGIC_LOW_RES_FACTOR; /* units/ms */
 	const double incline = accel_filter->incline * TP_MAGIC_LOW_RES_FACTOR;
 
 	speed_in *= TP_MAGIC_SLOWDOWN / TP_MAGIC_LOW_RES_FACTOR;
 
-	s1 = min(1, speed_in * 5 * 1000.0);
-	s2 = 1 + (speed_in  * 1000.0 - threshold * 1000.0) * incline;
+	s1 = min(1, speed_in * 5);
+	s2 = 1 + (speed_in - threshold) * incline;
 
 	speed_out = min(max_accel, s2 > 1 ? s2 : s1);
 
diff --git a/tools/ptraccel-debug.c b/tools/ptraccel-debug.c
index b0867db..1496763 100644
--- a/tools/ptraccel-debug.c
+++ b/tools/ptraccel-debug.c
@@ -147,12 +147,12 @@ print_accel_func(struct motion_filter *filter)
 	printf("# set ylabel \"raw accel factor\"\n");
 	printf("# set style data lines\n");
 	printf("# plot \"gnuplot.data\" using 1:2\n");
-	for (vel = 0.0; vel < 0.003; vel += 0.0000001) {
+	for (vel = 0.0; vel < 3.0; vel += .0001) {
 		double result = pointer_accel_profile_linear(filter,
                                                              NULL,
                                                              vel,
                                                              0 /* time */);
-		printf("%.8f\t%.4f\n", vel, result);
+		printf("%.4f\t%.4f\n", vel, result);
 	}
 }
 
-- 
2.4.3



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