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 <[email protected]> --- drivers/input/mouse/appletouch.c | 72 ++++++++++++++++++++++++++++---------- 1 file changed, 53 insertions(+), 19 deletions(-) diff --git a/drivers/input/mouse/appletouch.c b/drivers/input/mouse/appletouch.c index 2745832..0252bab 100644 --- a/drivers/input/mouse/appletouch.c +++ b/drivers/input/mouse/appletouch.c @@ -332,7 +332,11 @@ 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 + 8]; + int smooth_tmp[nb_sensors + 8]; + int scale = 12; + /* values to calculate mean */ int pcum = 0, psum = 0; int is_increasing = 0; @@ -344,9 +348,6 @@ static int atp_calculate_abs(int *xy_sensors, int nb_sensors, int fact, 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 @@ -361,27 +362,60 @@ static int atp_calculate_abs(int *xy_sensors, int nb_sensors, int fact, * * - Jason Parekh <[email protected]> */ - if (i < 1 || + + } else if (i < 1 || (!is_increasing && xy_sensors[i - 1] < xy_sensors[i])) { (*fingers)++; is_increasing = 1; } else if (i > 0 && (xy_sensors[i - 1] - xy_sensors[i] > threshold)) { 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); + /* + * Use a smoothed version of sensor data for movement calculations, to + * combat noise without needing to rely so heavily on a threshold. + * This improves tracking. + * + * The smoothed array is bigger than the original so that the smoothing + * doesn't result in edge values being truncated. + */ + + for (i = 0; i < 4; i++) + smooth[i] = 0; + for (i = nb_sensors + 4; i < nb_sensors + 8; i++) + smooth[i] = 0; + + /* Pull base values, scaled up to help avoid truncation errors. */ + + for (i = 0; i < nb_sensors; i++) + smooth[i + 4] = xy_sensors[i] << scale; + + for (k = 0; k < 4; k++) { + + /* Handle edge. */ + smooth_tmp[0] = (smooth[0] * 1 + smooth[1]) >> 1; + + /* Average values with neighbors. */ + for (i = 1; i < nb_sensors + 7; i++) + smooth_tmp[i] = (smooth[i - 1] + smooth[i] * 2 + smooth[i + 1]) >> 2; + + /* Handle other edge. */ + smooth_tmp[nb_sensors + 7] = (smooth[nb_sensors + 7] + smooth[nb_sensors + 6]) >> 1; + + for (i = 0; i < nb_sensors + 7; i++) + smooth[i] = smooth_tmp[i]; + } + + for (i = 0; i < nb_sensors + 8; i++) { + if ((smooth[i] >> scale) > 0) { /* Skip individual values if */ + pcum += (smooth[i]) * i; /* they are small enough to */ + psum += (smooth[i]); /* be truncated to 0 by our */ + } /* scale; mostly just noise. */ } if (psum > 0) { - *z = psum; + *z = psum >> scale; /* Scale down pressure output. */ return pcum * fact / psum; } @@ -559,8 +593,8 @@ 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; @@ -671,8 +705,8 @@ 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 -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
