[PATCH v2 weston] evdev: Mouse speed and acceleration
Peter Hutterer
peter.hutterer at who-t.net
Mon Apr 1 23:42:15 PDT 2013
On Sun, Mar 31, 2013 at 10:04:44PM +0200, Martin Minarik wrote:
> Computes an accurate velocity instead of approximation.
>
> Changes:
> Add disclaimer. Implements 8 acceleration profiles taken from X ptrveloc.c.
> The sampling has been fixed to handle eventual time overflow.
Since we added them I can't remember seeing a configuration that uses a
non-default acceleration profile. I don't think implementing multiple
profiles is really worthwhile. The only other profile that is really in use
is the synaptics one (which uses pressure-based accel) and that too
because it's the default.
Try to find a single accel method that is good enough for most cases and the
vast majority of users won't notice.
Cheers,
Peter
>
> Configuration:
> Tune the values in mouse_init().
>
> The tune_constant_coefficient is simply a multiplier of how fast
> the pointer moves. The 1.0 is the native device speed. Recommended:
>
> 0.03125 0.0625 0.25 0.5 0.75 1.0 1.5 2.0 2.5 3.0 3.5
>
> The tune_acceleration_profile is used to select one of the 8 profiles:
> http://www.x.org/wiki/Development/Documentation/PointerAcceleration#AccelerationProfiles
> To disable acceleration, use no_profile, number 0.
>
> tune_acceleration_treshold - should be a bit larger than 1.
> tune_min_multiplier - the multiplier when moving slow.
> tune_acc_multiplier - the multiplier when moving fast.
> ---
> src/Makefile.am | 4 +
> src/evdev-mouse.c | 467 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> src/evdev.c | 3 +
> src/evdev.h | 3 +
> 4 files changed, 477 insertions(+)
> create mode 100644 src/evdev-mouse.c
>
> diff --git a/src/Makefile.am b/src/Makefile.am
> index d56daa0..2c8b3eb 100644
> --- a/src/Makefile.am
> +++ b/src/Makefile.am
> @@ -138,6 +138,7 @@ drm_backend_la_SOURCES = \
> udev-seat.h \
> evdev.c \
> evdev.h \
> + evdev-mouse.c \
> evdev-touchpad.c \
> launcher-util.c \
> launcher-util.h \
> @@ -177,7 +178,9 @@ rpi_backend_la_SOURCES = \
> tty.c \
> evdev.c \
> evdev.h \
> + evdev-mouse.c \
> evdev-touchpad.c
> +
> endif
>
> if ENABLE_HEADLESS_COMPOSITOR
> @@ -211,6 +214,7 @@ fbdev_backend_la_SOURCES = \
> evdev.c \
> evdev.h \
> evdev-touchpad.c \
> + evdev-mouse.c \
> launcher-util.c
> endif
>
> diff --git a/src/evdev-mouse.c b/src/evdev-mouse.c
> new file mode 100644
> index 0000000..351eadc
> --- /dev/null
> +++ b/src/evdev-mouse.c
> @@ -0,0 +1,467 @@
> +/*
> + * Copyright ?? 2013 Martin Minarik
> + * Copyright ?? 2006-2009 Simon Thum
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
> + * DEALINGS IN THE SOFTWARE.
> + */
> +
> +#include <stdlib.h>
> +#include <stdbool.h>
> +
> +#include "compositor.h"
> +#include "evdev.h"
> +
> +#define DEFAULT_AXIS_STEP_DISTANCE wl_fixed_from_int(10)
> +#define MOUSE_MOTION_SAMPLING_PERIOD 32
> +
> +typedef double (*accel_velocity_func_t)(double min_acc, double velocity,
> + double threshold, double acc);
> +
> +/**
> + * just a smooth function in [0..1] -> [0..1]
> + * - point symmetry at 0.5
> + * - f'(0) = f'(1) = 0
> + * - starts faster than a sinoid
> + * - smoothness C1 (Cinf if you dare to ignore endpoints)
> + */
> +static inline double
> +calc_penumbral_gradient(double x)
> +{
> + x *= 2.0f;
> + x -= 1.0f;
> + return 0.5f + (x * sqrt(1.0 - x * x) + asin(x)) / M_PI;
> +}
> +
> +/*****************************************
> + * Acceleration functions and profiles
> + ****************************************/
> +
> +/**
> + * acceleration function similar to classic accelerated/unaccelerated,
> + * but with smooth transition in between (and towards zero for adaptive dec.).
> + */
> +static double
> +simple_smooth_profile(double min_acc,
> + double velocity, double threshold, double acc)
> +{
> + if (velocity < 1.0f)
> + return calc_penumbral_gradient(0.5 + velocity * 0.5) * 2.0f - 1.0f;
> + if (threshold < 1.0f)
> + threshold = 1.0f;
> + if (velocity <= threshold)
> + return 1;
> + velocity /= threshold;
> + if (velocity >= acc)
> + return acc;
> + else
> + return 1.0f + (calc_penumbral_gradient(velocity / acc) * (acc - 1.0f));
> +}
> +
> +/**
> + * Polynomial function similar previous one, but with f(1) = 1
> + */
> +static double
> +polynomial_acceleration_profile(double min_acc,
> + double velocity, double ignored, double acc)
> +{
> + return pow(velocity, (acc - 1.0) * 0.5);
> +}
> +
> +/**
> + * returns acceleration for velocity.
> + * This profile selects the two functions like the old scheme did
> + */
> +static double
> +classic_profile(double min_acc, double velocity, double threshold, double acc)
> +{
> + if (threshold > 0)
> + return simple_smooth_profile(min_acc, velocity, threshold, acc);
> + else
> + return polynomial_acceleration_profile(min_acc, velocity, 0, acc);
> +}
> +
> +/**
> + * Power profile
> + * This has a completely smooth transition curve, i.e. no jumps in the
> + * derivatives.
> + *
> + * This has the expense of overall response dependency on min-acceleration.
> + * In effect, min_acc mimics const_acceleration in this profile.
> + */
> +static double
> +power_profile(double min_acc, double velocity, double threshold, double acc)
> +{
> + double vel_dist;
> +
> + acc = (acc - 1.0) * 0.1f + 1.0;/* without this, acc of 2 is unuseable */
> +
> + if (velocity <= threshold)
> + return min_acc;
> + vel_dist = velocity - threshold;
> + return (pow(acc, vel_dist)) * min_acc;
> +}
> +
> +/**
> + * This profile uses the first half of the penumbral gradient as a start
> + * and then scales linearly.
> + */
> +static double
> +smooth_linear_profile(double min_acc, double velocity, double threshold, double acc)
> +{
> + double res, nv;
> +
> + if (acc > 1.0f)
> + acc -= 1.0f; /*this is so acc = 1 is no acceleration */
> + else
> + return 1.0f;
> +
> + nv = (velocity - threshold) * acc * 0.5f;
> +
> + if (nv < 0) {
> + res = 0;
> + }
> + else if (nv < 2) {
> + res = calc_penumbral_gradient(nv * 0.25f) * 2.0f;
> + } else {
> + nv -= 2.0f;
> + res = nv * 2.0f / M_PI /* steepness of gradient at 0.5 */
> + + 1.0f; /* gradient crosses 2|1 */
> + }
> + res += min_acc;
> + return res;
> +}
> +
> +/**
> + * From 0 to threshold, the response graduates smoothly from min_accel to
> + * acceleration. Beyond threshold it is exactly the specified acceleration.
> + */
> +static double
> +smooth_limited_profile(double min_acc, double velocity, double threshold, double acc)
> +{
> + double res;
> +
> + if (velocity >= threshold || threshold == 0.0f)
> + return acc;
> +
> + velocity /= threshold; /* should be [0..1[ now */
> +
> + res = calc_penumbral_gradient(velocity) * (acc - min_acc);
> +
> + return min_acc + res;
> +}
> +
> +static double
> +linear_profile(double min_acc, double velocity, double threshold, double acc)
> +{
> + return acc * velocity;
> +}
> +
> +static double
> +no_profile(double min_acc, double velocity, double threshold, double acc)
> +{
> + return 1.0f;
> +}
> +
> +static accel_velocity_func_t accel_profiles[8] = {
> + no_profile,
> + classic_profile,
> + polynomial_acceleration_profile,
> + smooth_linear_profile,
> + simple_smooth_profile,
> + power_profile,
> + linear_profile,
> + smooth_limited_profile
> +};
> +
> +/********************************************************/
> +
> +struct mouse_motion {
> + int32_t dx;
> + int32_t dy;
> +};
> +
> +struct mouse_dispatch {
> + struct evdev_dispatch base;
> + struct evdev_device *device;
> +
> + double actual_acceleration_factor;
> +
> + struct mouse_motion motion_sample;
> + uint32_t motion_period_id;
> + uint32_t motion_period_next;
> + double last_velocity;
> + double last_computed_acc;
> +
> + double tune_constant_coefficient;
> + accel_velocity_func_t tune_acceleration_profile;
> + double tune_min_multiplier;
> + double tune_acc_multiplier;
> + double tune_acceleration_treshold;
> +};
> +
> +static inline void
> +mouse_process_relative(struct mouse_dispatch *mouse,
> + struct evdev_device *device,
> + struct input_event *event, uint32_t time)
> +{
> + switch (event->code) {
> + case REL_X:
> + if (mouse->tune_acceleration_profile != no_profile)
> + mouse->motion_sample.dx += event->value;
> + device->rel.dx += wl_fixed_from_double((double) event->value *
> + mouse->actual_acceleration_factor);
> +
> + device->pending_events |= EVDEV_RELATIVE_MOTION;
> + break;
> + case REL_Y:
> + if (mouse->tune_acceleration_profile != no_profile)
> + mouse->motion_sample.dy += event->value;
> + device->rel.dy += wl_fixed_from_double((double) event->value *
> + mouse->actual_acceleration_factor);
> +
> + device->pending_events |= EVDEV_RELATIVE_MOTION;
> + break;
> + case REL_WHEEL:
> + switch (event->value) {
> + case -1:
> + /* Scroll down */
> + case 1:
> + /* Scroll up */
> + notify_axis(device->seat,
> + time,
> + WL_POINTER_AXIS_VERTICAL_SCROLL,
> + -1 * event->value * DEFAULT_AXIS_STEP_DISTANCE);
> + break;
> + default:
> + break;
> + }
> + break;
> + case REL_HWHEEL:
> + switch (event->value) {
> + case -1:
> + /* Scroll left */
> + case 1:
> + /* Scroll right */
> + notify_axis(device->seat,
> + time,
> + WL_POINTER_AXIS_HORIZONTAL_SCROLL,
> + event->value * DEFAULT_AXIS_STEP_DISTANCE);
> + break;
> + default:
> + break;
> +
> + }
> + }
> +}
> +
> +static inline void
> +mouse_process_key(struct mouse_dispatch *mouse,
> + struct evdev_device *device,
> + struct input_event *e,
> + uint32_t time)
> +{
> + if (e->value == 2)
> + return;
> +
> + switch (e->code) {
> + case BTN_LEFT:
> + case BTN_RIGHT:
> + case BTN_MIDDLE:
> + case BTN_SIDE:
> + case BTN_EXTRA:
> + case BTN_FORWARD:
> + case BTN_BACK:
> + case BTN_TASK:
> + notify_button(device->seat,
> + time, e->code,
> + e->value ? WL_POINTER_BUTTON_STATE_PRESSED :
> + WL_POINTER_BUTTON_STATE_RELEASED);
> + break;
> +
> + default:
> + notify_key(device->seat,
> + time, e->code,
> + e->value ? WL_KEYBOARD_KEY_STATE_PRESSED :
> + WL_KEYBOARD_KEY_STATE_RELEASED,
> + STATE_UPDATE_AUTOMATIC);
> + break;
> + }
> +}
> +
> +static void
> +mouse_sampler_reset(struct mouse_dispatch *m)
> +{
> + m->actual_acceleration_factor = m->tune_constant_coefficient *
> + m->tune_min_multiplier;
> + m->motion_sample.dx = 0;
> + m->motion_sample.dy = 0;
> + m->last_velocity = 0.0;
> + m->last_computed_acc = 0.0;
> +}
> +
> +static void
> +mouse_sampler_advance_period(struct mouse_dispatch *m, uint32_t time)
> +{
> + const unsigned long int period = MOUSE_MOTION_SAMPLING_PERIOD;
> + const uint32_t uint32max = ~0;
> +
> + m->motion_period_id = time / period;
> + m->motion_period_next = (uint32max & (time + period)) / period;
> +}
> +
> +static double
> +mouse_compute_acceleration(struct mouse_dispatch *m, double vel)
> +{
> + double computed;
> + computed = m->tune_acceleration_profile(m->tune_min_multiplier, vel,
> + m->tune_acceleration_treshold,
> + m->tune_acc_multiplier);
> +
> + if (computed < m->tune_min_multiplier)
> + return m->tune_min_multiplier;
> +
> + return computed;
> +}
> +
> +static void
> +mouse_sampler_apply_acceleration_mult(struct mouse_dispatch *m, uint32_t time)
> +{
> + struct mouse_motion *sample = &m->motion_sample;
> +
> + const unsigned long int period = MOUSE_MOTION_SAMPLING_PERIOD;
> +
> + unsigned long int distance_sq;
> + double velocity;
> + double velocity_avg;
> + double comp_acc;
> + double comp_acc_avg;
> + double mult;
> +
> + distance_sq = sample->dx * sample->dx + sample->dy * sample->dy;
> +
> + velocity = sqrtl(distance_sq) / period;
> + velocity_avg = (velocity + m->last_velocity) / 2.0;
> +
> + comp_acc = mouse_compute_acceleration(m, velocity);
> + comp_acc_avg = mouse_compute_acceleration(m, velocity_avg);
> +
> + /* Use Simpson's rule to calculate the avarage acceleration between
> + * the previous motion and the most recent. */
> + mult = (comp_acc + 4.0 * comp_acc_avg + m->last_computed_acc) * 0.16666;
> +
> + m->last_velocity = velocity;
> + m->last_computed_acc = comp_acc;
> + m->actual_acceleration_factor = m->tune_constant_coefficient * mult;
> + sample->dx = 0;
> + sample->dy = 0;
> +}
> +
> +static void
> +mouse_sampler_refresh(struct mouse_dispatch *m, uint32_t time)
> +{
> + uint32_t this_period_id = time / MOUSE_MOTION_SAMPLING_PERIOD;
> +
> + if (this_period_id != m->motion_period_id) {
> + if (this_period_id == m->motion_period_next) {
> + mouse_sampler_apply_acceleration_mult(m, time);
> + } else {
> + mouse_sampler_reset(m);
> + }
> + mouse_sampler_advance_period(m, time);
> + }
> +}
> +
> +static void
> +mouse_process(struct evdev_dispatch *dispatch,
> + struct evdev_device *device,
> + struct input_event *event,
> + uint32_t time)
> +{
> + struct mouse_dispatch *mouse =
> + (struct mouse_dispatch *) dispatch;
> +
> + switch (event->type) {
> + case EV_REL:
> + mouse_process_relative(mouse, device, event, time);
> + break;
> + case EV_KEY:
> + mouse_process_key(mouse, device, event, time);
> + break;
> + case EV_SYN:
> + device->pending_events |= EVDEV_SYN;
> +
> + if (mouse->tune_acceleration_profile != no_profile)
> + mouse_sampler_refresh(mouse, time);
> + break;
> + }
> +}
> +
> +static void
> +mouse_destroy(struct evdev_dispatch *dispatch)
> +{
> + struct mouse_dispatch *mouse =
> + (struct mouse_dispatch *) dispatch;
> +
> + free(mouse);
> +}
> +
> +struct evdev_dispatch_interface mouse_interface = {
> + mouse_process,
> + mouse_destroy
> +};
> +
> +static int
> +mouse_init(struct mouse_dispatch *mouse, struct evdev_device *device)
> +{
> + mouse->base.interface = &mouse_interface;
> + mouse->device = device;
> +
> + /* Configure mouse speed */
> + mouse->tune_constant_coefficient = 1.0;
> +
> + /* Configure mouse acceleration */
> + mouse->tune_acceleration_profile = accel_profiles[2];
> + mouse->tune_acceleration_treshold = 1.5;
> + mouse->tune_min_multiplier = 1.0;
> + mouse->tune_acc_multiplier = 3.0;
> +
> + /* Prepare motion sampling */
> + mouse_sampler_reset(mouse);
> + mouse_sampler_advance_period(mouse, 0);
> +
> + return 0;
> +}
> +
> +struct evdev_dispatch *
> +evdev_mouse_create(struct evdev_device *device)
> +{
> + struct mouse_dispatch *mouse;
> +
> + mouse = malloc(sizeof *mouse);
> + if (mouse == NULL)
> + return NULL;
> +
> + if (mouse_init(mouse, device) != 0) {
> + free(mouse);
> + return NULL;
> + }
> +
> + return &mouse->base;
> +}
> diff --git a/src/evdev.c b/src/evdev.c
> index d2954b5..bbad5ad 100644
> --- a/src/evdev.c
> +++ b/src/evdev.c
> @@ -459,6 +459,9 @@ evdev_handle_device(struct evdev_device *device)
> !TEST_BIT(key_bits, BTN_TOOL_PEN) &&
> has_abs)
> device->dispatch = evdev_touchpad_create(device);
> + else if (TEST_BIT(key_bits, BTN_LEFT) && !has_abs)
> + device->dispatch = evdev_mouse_create(device);
> +
> for (i = KEY_ESC; i < KEY_MAX; i++) {
> if (i >= BTN_MISC && i < KEY_OK)
> continue;
> diff --git a/src/evdev.h b/src/evdev.h
> index eb5c868..f670682 100644
> --- a/src/evdev.h
> +++ b/src/evdev.h
> @@ -111,6 +111,9 @@ struct evdev_dispatch {
> struct evdev_dispatch *
> evdev_touchpad_create(struct evdev_device *device);
>
> +struct evdev_dispatch *
> +evdev_mouse_create(struct evdev_device *device);
> +
> void
> evdev_led_update(struct evdev_device *device, enum weston_led leds);
>
> --
> 1.7.10.4
>
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