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authormarha <marha@users.sourceforge.net>2009-07-25 20:12:58 +0000
committermarha <marha@users.sourceforge.net>2009-07-25 20:12:58 +0000
commit2553bdd7c359cd87525d367761c86932cec5adff (patch)
treeae71245933c98474a699d3e392de5820879b2018 /xorg-server/dix/ptrveloc.c
parente2c51f2ee7b0a3ea1a052fc49324057b4a4bbc78 (diff)
parent4a3dbb926ae3f5410198d7cc4f4ebe4f62eebf05 (diff)
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svn merge file:///D:/svnrepos/vcxsrv/branches/released .
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diff --git a/xorg-server/dix/ptrveloc.c b/xorg-server/dix/ptrveloc.c
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+/*
+ *
+ * Copyright © 2006-2008 Simon Thum simon dot thum at gmx dot de
+ *
+ * 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.
+ */
+
+#ifdef HAVE_DIX_CONFIG_H
+#include <dix-config.h>
+#endif
+
+#include <math.h>
+#include <ptrveloc.h>
+#include <inputstr.h>
+#include <assert.h>
+#include <os.h>
+
+/*****************************************************************************
+ * Predictable pointer acceleration
+ *
+ * 2006-2008 by Simon Thum (simon [dot] thum [at] gmx de)
+ *
+ * Serves 3 complementary functions:
+ * 1) provide a sophisticated ballistic velocity estimate to improve
+ * the relation between velocity (of the device) and acceleration
+ * 2) make arbitrary acceleration profiles possible
+ * 3) decelerate by two means (constant and adaptive) if enabled
+ *
+ * Important concepts are the
+ *
+ * - Scheme
+ * which selects the basic algorithm
+ * (see devices.c/InitPointerAccelerationScheme)
+ * - Profile
+ * which returns an acceleration
+ * for a given velocity
+ *
+ * The profile can be selected by the user (potentially at runtime).
+ * the classic profile is intended to cleanly perform old-style
+ * function selection (threshold =/!= 0)
+ *
+ ****************************************************************************/
+
+/* fwds */
+static inline void
+FeedFilterStage(FilterStagePtr s, float value, int tdiff);
+extern void
+InitFilterStage(FilterStagePtr s, float rdecay, int lutsize);
+void
+CleanupFilterChain(DeviceVelocityPtr s);
+int
+SetAccelerationProfile(DeviceVelocityPtr s, int profile_num);
+void
+InitFilterChain(DeviceVelocityPtr s, float rdecay, float degression,
+ int stages, int lutsize);
+void
+CleanupFilterChain(DeviceVelocityPtr s);
+static float
+SimpleSmoothProfile(DeviceVelocityPtr pVel, float velocity,
+ float threshold, float acc);
+
+
+
+/*#define PTRACCEL_DEBUGGING*/
+
+#ifdef PTRACCEL_DEBUGGING
+#define DebugAccelF ErrorF
+#else
+#define DebugAccelF(...) /* */
+#endif
+
+/********************************
+ * Init/Uninit etc
+ *******************************/
+
+/**
+ * Init struct so it should match the average case
+ */
+void
+InitVelocityData(DeviceVelocityPtr s)
+{
+ memset(s, 0, sizeof(DeviceVelocityRec));
+
+ s->corr_mul = 10.0; /* dots per 10 milisecond should be usable */
+ s->const_acceleration = 1.0; /* no acceleration/deceleration */
+ s->reset_time = 300;
+ s->use_softening = 1;
+ s->min_acceleration = 1.0; /* don't decelerate */
+ s->coupling = 0.25;
+ s->average_accel = TRUE;
+ SetAccelerationProfile(s, AccelProfileClassic);
+ InitFilterChain(s, (float)1.0/20.0, 1, 1, 40);
+}
+
+
+/**
+ * Clean up
+ */
+static void
+FreeVelocityData(DeviceVelocityPtr s){
+ CleanupFilterChain(s);
+ SetAccelerationProfile(s, -1);
+}
+
+
+/*
+ * dix uninit helper, called through scheme
+ */
+void
+AccelerationDefaultCleanup(DeviceIntPtr pDev)
+{
+ /*sanity check*/
+ if( pDev->valuator->accelScheme.AccelSchemeProc == acceleratePointerPredictable
+ && pDev->valuator->accelScheme.accelData != NULL){
+ pDev->valuator->accelScheme.AccelSchemeProc = NULL;
+ FreeVelocityData(pDev->valuator->accelScheme.accelData);
+ xfree(pDev->valuator->accelScheme.accelData);
+ pDev->valuator->accelScheme.accelData = NULL;
+ }
+}
+
+/*********************
+ * Filtering logic
+ ********************/
+
+/**
+Initialize a filter chain.
+Expected result is a series of filters, each progressively more integrating.
+
+This allows for two strategies: Either you have one filter which is reasonable
+and is being coupled to account for fast-changing input, or you have 'one for
+every situation'. You might want to have tighter coupling then, e.g. 0.1.
+In the filter stats, you can see if a reasonable filter useage emerges.
+*/
+void
+InitFilterChain(DeviceVelocityPtr s, float rdecay, float progression, int stages, int lutsize)
+{
+ int fn;
+ if((stages > 1 && progression < 1.0f) || 0 == progression){
+ ErrorF("(dix ptracc) invalid filter chain progression specified\n");
+ return;
+ }
+ /* Block here to support runtime filter adjustment */
+ OsBlockSignals();
+ for(fn = 0; fn < MAX_VELOCITY_FILTERS; fn++){
+ if(fn < stages){
+ InitFilterStage(&s->filters[fn], rdecay, lutsize);
+ }else{
+ InitFilterStage(&s->filters[fn], 0, 0);
+ }
+ rdecay /= progression;
+ }
+ /* release again. Should the input loop be threaded, we also need
+ * memory release here (in principle).
+ */
+ OsReleaseSignals();
+}
+
+
+void
+CleanupFilterChain(DeviceVelocityPtr s)
+{
+ int fn;
+
+ for(fn = 0; fn < MAX_VELOCITY_FILTERS; fn++)
+ InitFilterStage(&s->filters[fn], 0, 0);
+}
+
+static inline void
+StuffFilterChain(DeviceVelocityPtr s, float value)
+{
+ int fn;
+
+ for(fn = 0; fn < MAX_VELOCITY_FILTERS; fn++){
+ if(s->filters[fn].rdecay != 0)
+ s->filters[fn].current = value;
+ else break;
+ }
+}
+
+
+/**
+ * Adjust weighting decay and lut for a stage
+ * The weight fn is designed so its integral 0->inf is unity, so we end
+ * up with a stable (basically IIR) filter. It always draws
+ * towards its more current input values, which have more weight the older
+ * the last input value is.
+ */
+void
+InitFilterStage(FilterStagePtr s, float rdecay, int lutsize)
+{
+ int x;
+ float *newlut;
+ float *oldlut;
+
+ s->fading_lut_size = 0; /* prevent access */
+
+ if(lutsize > 0){
+ newlut = xalloc (sizeof(float)* lutsize);
+ if(!newlut)
+ return;
+ for(x = 0; x < lutsize; x++)
+ newlut[x] = pow(0.5, ((float)x) * rdecay);
+ }else{
+ newlut = NULL;
+ }
+ oldlut = s->fading_lut;
+ s->fading_lut = newlut;
+ s->rdecay = rdecay;
+ s->fading_lut_size = lutsize;
+ s->current = 0;
+ if(oldlut != NULL)
+ xfree(oldlut);
+}
+
+
+static inline void
+FeedFilterChain(DeviceVelocityPtr s, float value, int tdiff)
+{
+ int fn;
+
+ for(fn = 0; fn < MAX_VELOCITY_FILTERS; fn++){
+ if(s->filters[fn].rdecay != 0)
+ FeedFilterStage(&s->filters[fn], value, tdiff);
+ else break;
+ }
+}
+
+
+static inline void
+FeedFilterStage(FilterStagePtr s, float value, int tdiff){
+ float fade;
+ if(tdiff < s->fading_lut_size)
+ fade = s->fading_lut[tdiff];
+ else
+ fade = pow(0.5, ((float)tdiff) * s->rdecay);
+ s->current *= fade; /* fade out old velocity */
+ s->current += value * (1.0f - fade); /* and add up current */
+}
+
+/**
+ * Select the most filtered matching result. Also, the first
+ * mismatching filter may be set to value (coupling).
+ */
+static inline float
+QueryFilterChain(
+ DeviceVelocityPtr s,
+ float value)
+{
+ int fn, rfn = 0, cfn = -1;
+ float cur, result = value;
+
+ /* try to retrieve most integrated result 'within range'
+ * Assumption: filter are in order least to most integrating */
+ for(fn = 0; fn < MAX_VELOCITY_FILTERS; fn++){
+ if(0.0f == s->filters[fn].rdecay)
+ break;
+ cur = s->filters[fn].current;
+
+ if (fabs(value - cur) <= (s->coupling * (value + cur))){
+ result = cur;
+ rfn = fn + 1; /*remember result determining filter */
+ } else if(cfn == -1){
+ cfn = fn; /* remember first mismatching filter */
+ }
+ }
+
+ s->statistics.filter_usecount[rfn]++;
+ DebugAccelF("(dix ptracc) result from stage %i, input %.2f, output %.2f\n",
+ rfn, value, result);
+
+ /* override first mismatching current (coupling) so the filter
+ * catches up quickly. */
+ if(cfn != -1)
+ s->filters[cfn].current = result;
+
+ return result;
+}
+
+/********************************
+ * velocity computation
+ *******************************/
+
+/**
+ * return the axis if mickey is insignificant and axis-aligned,
+ * -1 otherwise
+ * 1 for x-axis
+ * 2 for y-axis
+ */
+static inline short
+GetAxis(int dx, int dy){
+ if(dx == 0 || dy == 0){
+ if(dx == 1 || dx == -1)
+ return 1;
+ if(dy == 1 || dy == -1)
+ return 2;
+ return -1;
+ }else{
+ return -1;
+ }
+}
+
+
+/**
+ * Perform velocity approximation
+ * return true if non-visible state reset is suggested
+ */
+static short
+ProcessVelocityData(
+ DeviceVelocityPtr s,
+ int dx,
+ int dy,
+ int time)
+{
+ float cvelocity;
+
+ int diff = time - s->lrm_time;
+ int cur_ax, last_ax;
+ short reset = (diff >= s->reset_time);
+
+ /* remember last round's result */
+ s->last_velocity = s->velocity;
+ cur_ax = GetAxis(dx, dy);
+ last_ax = GetAxis(s->last_dx, s->last_dy);
+
+ if(cur_ax != last_ax && cur_ax != -1 && last_ax != -1 && !reset){
+ /* correct for the error induced when diagonal movements are
+ reported as alternating axis mickeys */
+ dx += s->last_dx;
+ dy += s->last_dy;
+ diff += s->last_diff;
+ s->last_diff = time - s->lrm_time; /* prevent repeating add-up */
+ DebugAccelF("(dix ptracc) axial correction\n");
+ }else{
+ s->last_diff = diff;
+ }
+
+ /*
+ * cvelocity is not a real velocity yet, more a motion delta. constant
+ * acceleration is multiplied here to make the velocity an on-screen
+ * velocity (pix/t as opposed to [insert unit]/t). This is intended to
+ * make multiple devices with widely varying ConstantDecelerations respond
+ * similar to acceleration controls.
+ */
+ cvelocity = (float)sqrt(dx*dx + dy*dy) * s->const_acceleration;
+
+ s->lrm_time = time;
+
+ if (s->reset_time < 0 || diff < 0) { /* reset disabled or timer overrun? */
+ /* simply set velocity from current movement, no reset. */
+ s->velocity = cvelocity;
+ return FALSE;
+ }
+
+ if (diff == 0)
+ diff = 1; /* prevent div-by-zero, though it shouldn't happen anyway*/
+
+ /* translate velocity to dots/ms (somewhat intractable in integers,
+ so we multiply by some per-device adjustable factor) */
+ cvelocity = cvelocity * s->corr_mul / (float)diff;
+
+ /* short-circuit: when nv-reset the rest can be skipped */
+ if(reset == TRUE){
+ /*
+ * we don't really have a velocity here, since diff includes inactive
+ * time. This is dealt with in ComputeAcceleration.
+ */
+ StuffFilterChain(s, cvelocity);
+ s->velocity = s->last_velocity = cvelocity;
+ s->last_reset = TRUE;
+ DebugAccelF("(dix ptracc) non-visible state reset\n");
+ return TRUE;
+ }
+
+ if(s->last_reset == TRUE){
+ /*
+ * when here, we're probably processing the second mickey of a starting
+ * stroke. This happens to be the first time we can reasonably pretend
+ * that cvelocity is an actual velocity. Thus, to opt precision, we
+ * stuff that into the filter chain.
+ */
+ s->last_reset = FALSE;
+ DebugAccelF("(dix ptracc) after-reset vel:%.3f\n", cvelocity);
+ StuffFilterChain(s, cvelocity);
+ s->velocity = cvelocity;
+ return FALSE;
+ }
+
+ /* feed into filter chain */
+ FeedFilterChain(s, cvelocity, diff);
+
+ /* perform coupling and decide final value */
+ s->velocity = QueryFilterChain(s, cvelocity);
+
+ DebugAccelF("(dix ptracc) guess: vel=%.3f diff=%d %i|%i|%i|%i|%i|%i|%i|%i|%i\n",
+ s->velocity, diff,
+ s->statistics.filter_usecount[0], s->statistics.filter_usecount[1],
+ s->statistics.filter_usecount[2], s->statistics.filter_usecount[3],
+ s->statistics.filter_usecount[4], s->statistics.filter_usecount[5],
+ s->statistics.filter_usecount[6], s->statistics.filter_usecount[7],
+ s->statistics.filter_usecount[8]);
+ return FALSE;
+}
+
+
+/**
+ * this flattens significant ( > 1) mickeys a little bit for more steady
+ * constant-velocity response
+ */
+static inline float
+ApplySimpleSoftening(int od, int d)
+{
+ float res = d;
+ if (d <= 1 && d >= -1)
+ return res;
+ if (d > od)
+ res -= 0.5;
+ else if (d < od)
+ res += 0.5;
+ return res;
+}
+
+
+static void
+ApplySofteningAndConstantDeceleration(
+ DeviceVelocityPtr s,
+ int dx,
+ int dy,
+ float* fdx,
+ float* fdy,
+ short do_soften)
+{
+ if (do_soften && s->use_softening) {
+ *fdx = ApplySimpleSoftening(s->last_dx, dx);
+ *fdy = ApplySimpleSoftening(s->last_dy, dy);
+ } else {
+ *fdx = dx;
+ *fdy = dy;
+ }
+
+ *fdx *= s->const_acceleration;
+ *fdy *= s->const_acceleration;
+}
+
+/*
+ * compute the acceleration for given velocity and enforce min_acceleartion
+ */
+static float
+BasicComputeAcceleration(
+ DeviceVelocityPtr pVel,
+ float velocity,
+ float threshold,
+ float acc){
+
+ float result;
+ result = pVel->Profile(pVel, velocity, threshold, acc);
+
+ /* enforce min_acceleration */
+ if (result < pVel->min_acceleration)
+ result = pVel->min_acceleration;
+ return result;
+}
+
+/**
+ * Compute acceleration. Takes into account averaging, nv-reset, etc.
+ */
+static float
+ComputeAcceleration(
+ DeviceVelocityPtr vel,
+ float threshold,
+ float acc){
+ float res;
+
+ if(vel->last_reset){
+ DebugAccelF("(dix ptracc) profile skipped\n");
+ /*
+ * This is intended to override the first estimate of a stroke,
+ * which is too low (see ProcessVelocityData). 1 should make sure
+ * the mickey is seen on screen.
+ */
+ return 1;
+ }
+
+ if(vel->average_accel && vel->velocity != vel->last_velocity){
+ /* use simpson's rule to average acceleration between
+ * current and previous velocity.
+ * Though being the more natural choice, it causes a minor delay
+ * in comparison, so it can be disabled. */
+ res = BasicComputeAcceleration(vel, vel->velocity, threshold, acc);
+ res += BasicComputeAcceleration(vel, vel->last_velocity, threshold, acc);
+ res += 4.0f * BasicComputeAcceleration(vel,
+ (vel->last_velocity + vel->velocity) / 2,
+ threshold, acc);
+ res /= 6.0f;
+ DebugAccelF("(dix ptracc) profile average [%.2f ... %.2f] is %.3f\n",
+ vel->velocity, vel->last_velocity, res);
+ return res;
+ }else{
+ res = BasicComputeAcceleration(vel, vel->velocity, threshold, acc);
+ DebugAccelF("(dix ptracc) profile sample [%.2f] is %.3f\n",
+ vel->velocity, res);
+ return res;
+ }
+}
+
+
+/*****************************************
+ * Acceleration functions and profiles
+ ****************************************/
+
+/**
+ * Polynomial function similar previous one, but with f(1) = 1
+ */
+static float
+PolynomialAccelerationProfile(
+ DeviceVelocityPtr pVel,
+ float velocity,
+ float ignored,
+ float 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 float
+ClassicProfile(
+ DeviceVelocityPtr pVel,
+ float velocity,
+ float threshold,
+ float acc)
+{
+ if (threshold) {
+ return SimpleSmoothProfile (pVel,
+ velocity,
+ threshold,
+ acc);
+ } else {
+ return PolynomialAccelerationProfile (pVel,
+ 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_acceleration mimics const_acceleration in this profile.
+ */
+static float
+PowerProfile(
+ DeviceVelocityPtr pVel,
+ float velocity,
+ float threshold,
+ float acc)
+{
+ float vel_dist;
+
+ acc = (acc-1.0) * 0.1f + 1.0; /* without this, acc of 2 is unuseable */
+
+ if (velocity <= threshold)
+ return pVel->min_acceleration;
+ vel_dist = velocity - threshold;
+ return (pow(acc, vel_dist)) * pVel->min_acceleration;
+}
+
+
+/**
+ * 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 float
+CalcPenumbralGradient(float x){
+ x *= 2.0f;
+ x -= 1.0f;
+ return 0.5f + (x * sqrt(1.0f - x*x) + asin(x))/M_PI;
+}
+
+
+/**
+ * acceleration function similar to classic accelerated/unaccelerated,
+ * but with smooth transition in between (and towards zero for adaptive dec.).
+ */
+static float
+SimpleSmoothProfile(
+ DeviceVelocityPtr pVel,
+ float velocity,
+ float threshold,
+ float acc)
+{
+ if(velocity < 1.0f)
+ return CalcPenumbralGradient(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 + (CalcPenumbralGradient(velocity/acc) * (acc - 1.0f));
+}
+
+
+/**
+ * This profile uses the first half of the penumbral gradient as a start
+ * and then scales linearly.
+ */
+static float
+SmoothLinearProfile(
+ DeviceVelocityPtr pVel,
+ float velocity,
+ float threshold,
+ float acc)
+{
+ float 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 = CalcPenumbralGradient(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 += pVel->min_acceleration;
+ return res;
+}
+
+
+static float
+LinearProfile(
+ DeviceVelocityPtr pVel,
+ float velocity,
+ float threshold,
+ float acc)
+{
+ return acc * velocity;
+}
+
+
+/**
+ * Set the profile by number.
+ * Intended to make profiles exchangeable at runtime.
+ * If you created a profile, give it a number here and in the header to
+ * make it selectable. In case some profile-specific init is needed, here
+ * would be a good place, since FreeVelocityData() also calls this with -1.
+ * returns FALSE (0) if profile number is unavailable.
+ */
+_X_EXPORT int
+SetAccelerationProfile(
+ DeviceVelocityPtr s,
+ int profile_num)
+{
+ PointerAccelerationProfileFunc profile;
+ switch(profile_num){
+ case -1:
+ profile = NULL; /* Special case to uninit properly */
+ break;
+ case AccelProfileClassic:
+ profile = ClassicProfile;
+ break;
+ case AccelProfileDeviceSpecific:
+ if(NULL == s->deviceSpecificProfile)
+ return FALSE;
+ profile = s->deviceSpecificProfile;
+ break;
+ case AccelProfilePolynomial:
+ profile = PolynomialAccelerationProfile;
+ break;
+ case AccelProfileSmoothLinear:
+ profile = SmoothLinearProfile;
+ break;
+ case AccelProfileSimple:
+ profile = SimpleSmoothProfile;
+ break;
+ case AccelProfilePower:
+ profile = PowerProfile;
+ break;
+ case AccelProfileLinear:
+ profile = LinearProfile;
+ break;
+ case AccelProfileReserved:
+ /* reserved for future use, e.g. a user-defined profile */
+ default:
+ return FALSE;
+ }
+ if(s->profile_private != NULL){
+ /* Here one could free old profile-private data */
+ xfree(s->profile_private);
+ s->profile_private = NULL;
+ }
+ /* Here one could init profile-private data */
+ s->Profile = profile;
+ s->statistics.profile_number = profile_num;
+ return TRUE;
+}
+
+/**********************************************
+ * driver interaction
+ **********************************************/
+
+
+/**
+ * device-specific profile
+ *
+ * The device-specific profile is intended as a hook for a driver
+ * which may want to provide an own acceleration profile.
+ * It should not rely on profile-private data, instead
+ * it should do init/uninit in the driver (ie. with DEVICE_INIT and friends).
+ * Users may override or choose it.
+ */
+_X_EXPORT void
+SetDeviceSpecificAccelerationProfile(
+ DeviceVelocityPtr s,
+ PointerAccelerationProfileFunc profile)
+{
+ if(s)
+ s->deviceSpecificProfile = profile;
+}
+
+/**
+ * Use this function to obtain a DeviceVelocityPtr for a device. Will return NULL if
+ * the predictable acceleration scheme is not in effect.
+ */
+_X_EXPORT DeviceVelocityPtr
+GetDevicePredictableAccelData(
+ DeviceIntPtr pDev)
+{
+ /*sanity check*/
+ if(!pDev){
+ ErrorF("[dix] accel: DeviceIntPtr was NULL");
+ return NULL;
+ }
+ if( pDev->valuator &&
+ pDev->valuator->accelScheme.AccelSchemeProc ==
+ acceleratePointerPredictable &&
+ pDev->valuator->accelScheme.accelData != NULL){
+
+ return (DeviceVelocityPtr)pDev->valuator->accelScheme.accelData;
+ }
+ return NULL;
+}
+
+/********************************
+ * acceleration schemes
+ *******************************/
+
+/**
+ * Modifies valuators in-place.
+ * This version employs a velocity approximation algorithm to
+ * enable fine-grained predictable acceleration profiles.
+ */
+void
+acceleratePointerPredictable(
+ DeviceIntPtr pDev,
+ int first_valuator,
+ int num_valuators,
+ int *valuators,
+ int evtime)
+{
+ float mult = 0.0;
+ int dx = 0, dy = 0;
+ int *px = NULL, *py = NULL;
+ DeviceVelocityPtr velocitydata =
+ (DeviceVelocityPtr) pDev->valuator->accelScheme.accelData;
+ float fdx, fdy; /* no need to init */
+
+ if (!num_valuators || !valuators || !velocitydata)
+ return;
+
+ if (first_valuator == 0) {
+ dx = valuators[0];
+ px = &valuators[0];
+ }
+ if (first_valuator <= 1 && num_valuators >= (2 - first_valuator)) {
+ dy = valuators[1 - first_valuator];
+ py = &valuators[1 - first_valuator];
+ }
+
+ if (dx || dy){
+ /* reset nonvisible state? */
+ if (ProcessVelocityData(velocitydata, dx , dy, evtime)) {
+ /* set to center of pixel. makes sense as long as there are no
+ * means of passing on sub-pixel values.
+ */
+ pDev->last.remainder[0] = pDev->last.remainder[1] = 0.5f;
+ /* prevent softening (somewhat quirky solution,
+ as it depends on the algorithm) */
+ velocitydata->last_dx = dx;
+ velocitydata->last_dy = dy;
+ }
+
+ if (pDev->ptrfeed && pDev->ptrfeed->ctrl.num) {
+ /* invoke acceleration profile to determine acceleration */
+ mult = ComputeAcceleration (velocitydata,
+ pDev->ptrfeed->ctrl.threshold,
+ (float)pDev->ptrfeed->ctrl.num /
+ (float)pDev->ptrfeed->ctrl.den);
+
+ if(mult != 1.0 || velocitydata->const_acceleration != 1.0) {
+ ApplySofteningAndConstantDeceleration( velocitydata,
+ dx, dy,
+ &fdx, &fdy,
+ mult > 1.0);
+ if (dx) {
+ pDev->last.remainder[0] = mult * fdx + pDev->last.remainder[0];
+ *px = (int)pDev->last.remainder[0];
+ pDev->last.remainder[0] = pDev->last.remainder[0] - (float)*px;
+ }
+ if (dy) {
+ pDev->last.remainder[1] = mult * fdy + pDev->last.remainder[1];
+ *py = (int)pDev->last.remainder[1];
+ pDev->last.remainder[1] = pDev->last.remainder[1] - (float)*py;
+ }
+ }
+ }
+ }
+ /* remember last motion delta (for softening/slow movement treatment) */
+ velocitydata->last_dx = dx;
+ velocitydata->last_dy = dy;
+}
+
+
+
+/**
+ * Originally a part of xf86PostMotionEvent; modifies valuators
+ * in-place. Retained mostly for embedded scenarios.
+ */
+void
+acceleratePointerLightweight(
+ DeviceIntPtr pDev,
+ int first_valuator,
+ int num_valuators,
+ int *valuators,
+ int ignored)
+{
+ float mult = 0.0;
+ int dx = 0, dy = 0;
+ int *px = NULL, *py = NULL;
+
+ if (!num_valuators || !valuators)
+ return;
+
+ if (first_valuator == 0) {
+ dx = valuators[0];
+ px = &valuators[0];
+ }
+ if (first_valuator <= 1 && num_valuators >= (2 - first_valuator)) {
+ dy = valuators[1 - first_valuator];
+ py = &valuators[1 - first_valuator];
+ }
+
+ if (!dx && !dy)
+ return;
+
+ if (pDev->ptrfeed && pDev->ptrfeed->ctrl.num) {
+ /* modeled from xf86Events.c */
+ if (pDev->ptrfeed->ctrl.threshold) {
+ if ((abs(dx) + abs(dy)) >= pDev->ptrfeed->ctrl.threshold) {
+ pDev->last.remainder[0] = ((float)dx *
+ (float)(pDev->ptrfeed->ctrl.num)) /
+ (float)(pDev->ptrfeed->ctrl.den) +
+ pDev->last.remainder[0];
+ if (px) {
+ *px = (int)pDev->last.remainder[0];
+ pDev->last.remainder[0] = pDev->last.remainder[0] -
+ (float)(*px);
+ }
+
+ pDev->last.remainder[1] = ((float)dy *
+ (float)(pDev->ptrfeed->ctrl.num)) /
+ (float)(pDev->ptrfeed->ctrl.den) +
+ pDev->last.remainder[1];
+ if (py) {
+ *py = (int)pDev->last.remainder[1];
+ pDev->last.remainder[1] = pDev->last.remainder[1] -
+ (float)(*py);
+ }
+ }
+ }
+ else {
+ mult = pow((float)dx * (float)dx + (float)dy * (float)dy,
+ ((float)(pDev->ptrfeed->ctrl.num) /
+ (float)(pDev->ptrfeed->ctrl.den) - 1.0) /
+ 2.0) / 2.0;
+ if (dx) {
+ pDev->last.remainder[0] = mult * (float)dx +
+ pDev->last.remainder[0];
+ *px = (int)pDev->last.remainder[0];
+ pDev->last.remainder[0] = pDev->last.remainder[0] -
+ (float)(*px);
+ }
+ if (dy) {
+ pDev->last.remainder[1] = mult * (float)dy +
+ pDev->last.remainder[1];
+ *py = (int)pDev->last.remainder[1];
+ pDev->last.remainder[1] = pDev->last.remainder[1] -
+ (float)(*py);
+ }
+ }
+ }
+}