Use smoothed version of sensor array data to calculate movement and add weight to prior values when calculating average. This gives more granular and more predictable movement.
Signed-off-by: Clinton Sprain <clintonsprain@xxxxxxxxx>
---
drivers/input/mouse/appletouch.c | 60 ++++++++++++++++++++++++++------------
1 file changed, 42 insertions(+), 18 deletions(-)
diff --git a/drivers/input/mouse/appletouch.c b/drivers/input/mouse/appletouch.c
index d48181b..edbdd95 100644
--- a/drivers/input/mouse/appletouch.c
+++ b/drivers/input/mouse/appletouch.c
@@ -338,21 +338,51 @@ static void atp_reinit(struct work_struct *work)
static int atp_calculate_abs(int *xy_sensors, int nb_sensors, int fact,
int *z, int *fingers)
{
- int i;
+ int i, k;
+ int smooth[nb_sensors + 2];
+ int smooth_tmp[nb_sensors + 2];
+
/* values to calculate mean */
int pcum = 0, psum = 0;
int is_increasing = 0;
*fingers = 0;
+ /*
+ * Use a smoothed version of sensor data for movement calculations, to
+ * combat noise without needing to toss out values based on a threshold.
+ * This improves tracking. Finger count is calculated separately based
+ * on raw data.
+ */
+
+ for (i = 0; i < nb_sensors; i++) { /* Scale up to minimize */
+ smooth[i] = xy_sensors[i] << 12; /* rounding/truncation. */
+ }
+
+ /* Mitigate some of the data loss from smoothing on the edge sensors. */
+ smooth[-1] = smooth[0] >> 2;
+ smooth[nb_sensors] = smooth[nb_sensors - 1] >> 2;
+
+ for (k = 0; k < 4; k++) {
+ for (i = 0; i < nb_sensors; i++) { /* Blend with neighbors. */
+ smooth_tmp[i] = (smooth[i - 1] + smooth[i] * 2 + smooth[i + 1]) >> 2;
+ }
+
+ for (i = 0; i < nb_sensors; i++) {
+ smooth[i] = smooth_tmp[i];
+ if (k == 3) /* Last go-round, so scale back down. */
+ smooth[i] = smooth[i] >> 12;
+ }
+
+ smooth[-1] = smooth[0] >> 2;
+ smooth[nb_sensors] = smooth[nb_sensors - 1] >> 2;
+ }
+
for (i = 0; i < nb_sensors; i++) {
if (xy_sensors[i] < threshold) {
if (is_increasing)
is_increasing = 0;
- continue;
- }
-
/*
* Makes the finger detection more versatile. For example,
* two fingers with no gap will be detected. Also, my
@@ -367,7 +397,8 @@ static int atp_calculate_abs(int *xy_sensors, int nb_sensors, int fact,
*
* - Jason Parekh <jasonparekh@xxxxxxxxx>
*/
- if (i < 1 ||
+
+ } else if (i < 1 ||
(!is_increasing && xy_sensors[i - 1] < xy_sensors[i])) {
(*fingers)++;
is_increasing = 1;
@@ -375,15 +406,8 @@ static int atp_calculate_abs(int *xy_sensors, int nb_sensors, int fact,
is_increasing = 0;
}
- /*
- * Subtracts threshold so a high sensor that just passes the
- * threshold won't skew the calculated absolute coordinate.
- * Fixes an issue where slowly moving the mouse would
- * occasionally jump a number of pixels (slowly moving the
- * finger makes this issue most apparent.)
- */
- pcum += (xy_sensors[i] - threshold) * i;
- psum += (xy_sensors[i] - threshold);
+ pcum += (smooth[i]) * i;
+ psum += (smooth[i]);
}
if (psum > 0) {
@@ -565,8 +589,8 @@ static void atp_complete_geyser_1_2(struct urb *urb)
if (x && y) {
if (dev->x_old != -1) {
- x = (dev->x_old * 3 + x) >> 2;
- y = (dev->y_old * 3 + y) >> 2;
+ x = (dev->x_old * 7 + x) >> 3;
+ y = (dev->y_old * 7 + y) >> 3;
dev->x_old = x;
dev->y_old = y;
@@ -677,8 +701,8 @@ static void atp_complete_geyser_3_4(struct urb *urb)
if (x && y) {
if (dev->x_old != -1) {
- x = (dev->x_old * 3 + x) >> 2;
- y = (dev->y_old * 3 + y) >> 2;
+ x = (dev->x_old * 7 + x) >> 3;
+ y = (dev->y_old * 7 + y) >> 3;
dev->x_old = x;
dev->y_old = y;
--
1.7.9.5
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