src/evdev-mt-touchpad.c

   1 /*
   2  * Copyright © 2014 Red Hat, Inc.
   3  *
   4  * Permission to use, copy, modify, distribute, and sell this software and
   5  * its documentation for any purpose is hereby granted without fee, provided
   6  * that the above copyright notice appear in all copies and that both that
   7  * copyright notice and this permission notice appear in supporting
   8  * documentation, and that the name of the copyright holders not be used in
   9  * advertising or publicity pertaining to distribution of the software
  10  * without specific, written prior permission.  The copyright holders make
  11  * no representations about the suitability of this software for any
  12  * purpose.  It is provided "as is" without express or implied warranty.
  13  *
  14  * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
  15  * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
  16  * FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
  17  * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
  18  * RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
  19  * CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
  20  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  21  */
  22
  23 #include "config.h"
  24
  25 #include <assert.h>
  26 #include <math.h>
  27 #include <stdbool.h>
  28
  29 #include "evdev-mt-touchpad.h"
  30
  31 #define DEFAULT_CONSTANT_ACCEL_NUMERATOR 50
  32 #define DEFAULT_MIN_ACCEL_FACTOR 0.16
  33 #define DEFAULT_MAX_ACCEL_FACTOR 1.0
  34 #define DEFAULT_HYSTERESIS_MARGIN_DENOMINATOR 700.0
  35
  36 static inline int
  37 tp_hysteresis(int in, int center, int margin)
  38 {
  39         int diff = in - center;
  40         if (abs(diff) <= margin)
  41                 return center;
  42
  43         if (diff > margin)
  44                 return center + diff - margin;
  45         else if (diff < -margin)
  46                 return center + diff + margin;
  47         return center + diff;
  48 }
  49
  50 static double
  51 tp_accel_profile(struct motion_filter *filter,
  52                  void *data,
  53                  double velocity,
  54                  uint32_t time)
  55 {
  56         struct tp_dispatch *tp =
  57                 (struct tp_dispatch *) data;
  58
  59         double accel_factor;
  60
  61         accel_factor = velocity * tp->accel.constant_factor;
  62
  63         if (accel_factor > tp->accel.max_factor)
  64                 accel_factor = tp->accel.max_factor;
  65         else if (accel_factor < tp->accel.min_factor)
  66                 accel_factor = tp->accel.min_factor;
  67
  68         return accel_factor;
  69 }
  70
  71 static inline struct tp_motion *
  72 tp_motion_history_offset(struct tp_touch *t, int offset)
  73 {
  74         int offset_index =
  75                 (t->history.index - offset + TOUCHPAD_HISTORY_LENGTH) %
  76                 TOUCHPAD_HISTORY_LENGTH;
  77
  78         return &t->history.samples[offset_index];
  79 }
  80
  81 static void
  82 tp_filter_motion(struct tp_dispatch *tp,
  83                  double *dx, double *dy, uint32_t time)
  84 {
  85         struct motion_params motion;
  86
  87         motion.dx = *dx;
  88         motion.dy = *dy;
  89
  90         filter_dispatch(tp->filter, &motion, tp, time);
  91
  92         *dx = motion.dx;
  93         *dy = motion.dy;
  94 }
  95
  96 static inline void
  97 tp_motion_history_push(struct tp_touch *t)
  98 {
  99         int motion_index = (t->history.index + 1) % TOUCHPAD_HISTORY_LENGTH;
 100
 101         if (t->history.count < TOUCHPAD_HISTORY_LENGTH)
 102                 t->history.count++;
 103
 104         t->history.samples[motion_index].x = t->x;
 105         t->history.samples[motion_index].y = t->y;
 106         t->history.index = motion_index;
 107 }
 108
 109 static inline void
 110 tp_motion_hysteresis(struct tp_dispatch *tp,
 111                      struct tp_touch *t)
 112 {
 113         int x = t->x,
 114             y = t->y;
 115
 116         if (t->history.count == 0) {
 117                 t->hysteresis.center_x = t->x;
 118                 t->hysteresis.center_y = t->y;
 119         } else {
 120                 x = tp_hysteresis(x,
 121                                   t->hysteresis.center_x,
 122                                   tp->hysteresis.margin_x);
 123                 y = tp_hysteresis(y,
 124                                   t->hysteresis.center_y,
 125                                   tp->hysteresis.margin_y);
 126                 t->hysteresis.center_x = x;
 127                 t->hysteresis.center_y = y;
 128                 t->x = x;
 129                 t->y = y;
 130         }
 131 }
 132
 133 static inline void
 134 tp_motion_history_reset(struct tp_touch *t)
 135 {
 136         t->history.count = 0;
 137 }
 138
 139 static inline struct tp_touch *
 140 tp_current_touch(struct tp_dispatch *tp)
 141 {
 142         return &tp->touches[min(tp->slot, tp->ntouches)];
 143 }
 144
 145 static inline struct tp_touch *
 146 tp_get_touch(struct tp_dispatch *tp, unsigned int slot)
 147 {
 148         assert(slot < tp->ntouches);
 149         return &tp->touches[slot];
 150 }
 151
 152 static inline void
 153 tp_begin_touch(struct tp_dispatch *tp, struct tp_touch *t)
 154 {
 155         struct tp_touch *tmp;
 156
 157         if (t->state != TOUCH_UPDATE) {
 158                 tp_motion_history_reset(t);
 159                 t->dirty = true;
 160                 t->state = TOUCH_BEGIN;
 161                 tp->nfingers_down++;
 162                 assert(tp->nfingers_down >= 1);
 163                 tp->queued |= TOUCHPAD_EVENT_MOTION;
 164
 165                 tp_for_each_touch(tp, tmp) {
 166                         if (tmp->is_pointer)
 167                                 break;
 168                 }
 169
 170                 if (!tmp->is_pointer) {
 171                         t->is_pointer = true;
 172                 }
 173         }
 174 }
 175
 176 static inline void
 177 tp_end_touch(struct tp_dispatch *tp, struct tp_touch *t)
 178 {
 179         if (t->state == TOUCH_NONE)
 180                 return;
 181
 182         t->dirty = true;
 183         t->is_pointer = false;
 184         t->state = TOUCH_END;
 185         assert(tp->nfingers_down >= 1);
 186         tp->nfingers_down--;
 187         tp->queued |= TOUCHPAD_EVENT_MOTION;
 188 }
 189
 190 static double
 191 tp_estimate_delta(int x0, int x1, int x2, int x3)
 192 {
 193         return (x0 + x1 - x2 - x3) / 4;
 194 }
 195
 196 void
 197 tp_get_delta(struct tp_touch *t, double *dx, double *dy)
 198 {
 199         if (t->history.count < 4) {
 200                 *dx = 0;
 201                 *dy = 0;
 202                 return;
 203         }
 204
 205         *dx = tp_estimate_delta(tp_motion_history_offset(t, 0)->x,
 206                                 tp_motion_history_offset(t, 1)->x,
 207                                 tp_motion_history_offset(t, 2)->x,
 208                                 tp_motion_history_offset(t, 3)->x);
 209         *dy = tp_estimate_delta(tp_motion_history_offset(t, 0)->y,
 210                                 tp_motion_history_offset(t, 1)->y,
 211                                 tp_motion_history_offset(t, 2)->y,
 212                                 tp_motion_history_offset(t, 3)->y);
 213 }
 214
 215 static void
 216 tp_process_absolute(struct tp_dispatch *tp,
 217                     const struct input_event *e,
 218                     uint32_t time)
 219 {
 220         struct tp_touch *t = tp_current_touch(tp);
 221
 222         switch(e->code) {
 223         case ABS_MT_POSITION_X:
 224                 t->x = e->value;
 225                 t->millis = time;
 226                 t->dirty = true;
 227                 tp->queued |= TOUCHPAD_EVENT_MOTION;
 228                 break;
 229         case ABS_MT_POSITION_Y:
 230                 t->y = e->value;
 231                 t->millis = time;
 232                 t->dirty = true;
 233                 tp->queued |= TOUCHPAD_EVENT_MOTION;
 234                 break;
 235         case ABS_MT_SLOT:
 236                 tp->slot = e->value;
 237                 break;
 238         case ABS_MT_TRACKING_ID:
 239                 t->millis = time;
 240                 if (e->value != -1)
 241                         tp_begin_touch(tp, t);
 242                 else
 243                         tp_end_touch(tp, t);
 244         }
 245 }
 246
 247 static void
 248 tp_process_absolute_st(struct tp_dispatch *tp,
 249                        const struct input_event *e,
 250                        uint32_t time)
 251 {
 252         struct tp_touch *t = tp_current_touch(tp);
 253
 254         switch(e->code) {
 255         case ABS_X:
 256                 t->x = e->value;
 257                 t->millis = time;
 258                 t->dirty = true;
 259                 break;
 260         case ABS_Y:
 261                 t->y = e->value;
 262                 t->millis = time;
 263                 t->dirty = true;
 264                 tp->queued |= TOUCHPAD_EVENT_MOTION;
 265                 break;
 266         }
 267 }
 268
 269 static void
 270 tp_process_fake_touch(struct tp_dispatch *tp,
 271                       const struct input_event *e,
 272                       uint32_t time)
 273 {
 274         struct tp_touch *t;
 275         unsigned int fake_touches;
 276         unsigned int nfake_touches;
 277         unsigned int i;
 278         unsigned int shift;
 279
 280         if (e->code != BTN_TOUCH &&
 281             (e->code < BTN_TOOL_DOUBLETAP || e->code > BTN_TOOL_QUADTAP))
 282                 return;
 283
 284         shift = e->code == BTN_TOUCH ? 0 : (e->code - BTN_TOOL_DOUBLETAP + 1);
 285
 286         if (e->value)
 287                 tp->fake_touches |= 1 << shift;
 288         else
 289                 tp->fake_touches &= ~(0x1 << shift);
 290
 291         fake_touches = tp->fake_touches;
 292         nfake_touches = 0;
 293         while (fake_touches) {
 294                 nfake_touches++;
 295                 fake_touches >>= 1;
 296         }
 297
 298         for (i = 0; i < tp->ntouches; i++) {
 299                 t = tp_get_touch(tp, i);
 300                 if (i >= nfake_touches) {
 301                         if (t->state != TOUCH_NONE) {
 302                                 tp_end_touch(tp, t);
 303                                 t->millis = time;
 304                         }
 305                 } else if (t->state != TOUCH_UPDATE &&
 306                            t->state != TOUCH_BEGIN) {
 307                         t->state = TOUCH_NONE;
 308                         tp_begin_touch(tp, t);
 309                         t->millis = time;
 310                         t->fake =true;
 311                 }
 312         }
 313
 314         assert(tp->nfingers_down == nfake_touches);
 315 }
 316
 317 static void
 318 tp_process_key(struct tp_dispatch *tp,
 319                const struct input_event *e,
 320                uint32_t time)
 321 {
 322         uint32_t mask;
 323
 324         switch (e->code) {
 325                 case BTN_LEFT:
 326                 case BTN_MIDDLE:
 327                 case BTN_RIGHT:
 328                         mask = 1 << (e->code - BTN_LEFT);
 329                         if (e->value) {
 330                                 tp->buttons.state |= mask;
 331                                 tp->queued |= TOUCHPAD_EVENT_BUTTON_PRESS;
 332                         } else {
 333                                 tp->buttons.state &= ~mask;
 334                                 tp->queued |= TOUCHPAD_EVENT_BUTTON_RELEASE;
 335                         }
 336                         break;
 337                 case BTN_TOUCH:
 338                 case BTN_TOOL_DOUBLETAP:
 339                 case BTN_TOOL_TRIPLETAP:
 340                 case BTN_TOOL_QUADTAP:
 341                         if (!tp->has_mt)
 342                                 tp_process_fake_touch(tp, e, time);
 343                         break;
 344         }
 345 }
 346
 347 static void
 348 tp_unpin_finger(struct tp_dispatch *tp)
 349 {
 350         struct tp_touch *t;
 351         tp_for_each_touch(tp, t) {
 352                 if (t->is_pinned) {
 353                         t->is_pinned = false;
 354
 355                         if (t->state != TOUCH_END &&
 356                             tp->nfingers_down == 1)
 357                                 t->is_pointer = true;
 358                         break;
 359                 }
 360         }
 361 }
 362
 363 static void
 364 tp_pin_finger(struct tp_dispatch *tp)
 365 {
 366         struct tp_touch *t,
 367                         *pinned = NULL;
 368
 369         tp_for_each_touch(tp, t) {
 370                 if (t->is_pinned) {
 371                         pinned = t;
 372                         break;
 373                 }
 374         }
 375
 376         assert(!pinned);
 377
 378         pinned = tp_current_touch(tp);
 379
 380         if (tp->nfingers_down != 1) {
 381                 tp_for_each_touch(tp, t) {
 382                         if (t == pinned)
 383                                 continue;
 384
 385                         if (t->y > pinned->y)
 386                                 pinned = t;
 387                 }
 388         }
 389
 390         pinned->is_pinned = true;
 391         pinned->is_pointer = false;
 392 }
 393
 394 static void
 395 tp_process_state(struct tp_dispatch *tp, uint32_t time)
 396 {
 397         struct tp_touch *t;
 398         struct tp_touch *first = tp_get_touch(tp, 0);
 399
 400         tp_for_each_touch(tp, t) {
 401                 if (!tp->has_mt && t != first && first->fake) {
 402                         t->x = first->x;
 403                         t->y = first->y;
 404                         if (!t->dirty)
 405                                 t->dirty = first->dirty;
 406                 } else if (!t->dirty)
 407                         continue;
 408
 409                 tp_motion_hysteresis(tp, t);
 410                 tp_motion_history_push(t);
 411         }
 412
 413         /* We have a physical button down event on a clickpad. For drag and
 414            drop, this means we try to identify which finger pressed the
 415            physical button and "pin" it, i.e. remove pointer-moving
 416            capabilities from it.
 417          */
 418         if ((tp->queued & TOUCHPAD_EVENT_BUTTON_PRESS) &&
 419             !tp->buttons.has_buttons)
 420                 tp_pin_finger(tp);
 421 }
 422
 423 static void
 424 tp_post_process_state(struct tp_dispatch *tp, uint32_t time)
 425 {
 426         struct tp_touch *t;
 427
 428         tp_for_each_touch(tp, t) {
 429                 if (!t->dirty)
 430                         continue;
 431
 432                 if (t->state == TOUCH_END) {
 433                         t->state = TOUCH_NONE;
 434                         t->fake = false;
 435                 } else if (t->state == TOUCH_BEGIN)
 436                         t->state = TOUCH_UPDATE;
 437
 438                 t->dirty = false;
 439         }
 440
 441         tp->buttons.old_state = tp->buttons.state;
 442
 443         if (tp->queued & TOUCHPAD_EVENT_BUTTON_RELEASE)
 444                 tp_unpin_finger(tp);
 445
 446         tp->queued = TOUCHPAD_EVENT_NONE;
 447 }
 448
 449 static void
 450 tp_post_twofinger_scroll(struct tp_dispatch *tp, uint32_t time)
 451 {
 452         struct tp_touch *t;
 453         int nchanged = 0;
 454         double dx = 0, dy =0;
 455         double tmpx, tmpy;
 456
 457         tp_for_each_touch(tp, t) {
 458                 if (t->dirty) {
 459                         nchanged++;
 460                         tp_get_delta(t, &tmpx, &tmpy);
 461
 462                         dx += tmpx;
 463                         dy += tmpy;
 464                 }
 465         }
 466
 467         if (nchanged == 0)
 468                 return;
 469
 470         dx /= nchanged;
 471         dy /= nchanged;
 472
 473         tp_filter_motion(tp, &dx, &dy, time);
 474
 475         if (tp->scroll.state == SCROLL_STATE_NONE) {
 476                 /* Require at least one px scrolling to start */
 477                 if (dx <= -1.0 || dx >= 1.0) {
 478                         tp->scroll.state = SCROLL_STATE_SCROLLING;
 479                         tp->scroll.direction |= (1 << LIBINPUT_POINTER_AXIS_HORIZONTAL_SCROLL);
 480                 }
 481
 482                 if (dy <= -1.0 || dy >= 1.0) {
 483                         tp->scroll.state = SCROLL_STATE_SCROLLING;
 484                         tp->scroll.direction |= (1 << LIBINPUT_POINTER_AXIS_VERTICAL_SCROLL);
 485                 }
 486
 487                 if (tp->scroll.state == SCROLL_STATE_NONE)
 488                         return;
 489         }
 490
 491         if (dy != 0.0 &&
 492             (tp->scroll.direction & (1 << LIBINPUT_POINTER_AXIS_VERTICAL_SCROLL))) {
 493                 pointer_notify_axis(&tp->device->base,
 494                                     time,
 495                                     LIBINPUT_POINTER_AXIS_VERTICAL_SCROLL,
 496                                     li_fixed_from_double(dy));
 497         }
 498
 499         if (dx != 0.0 &&
 500             (tp->scroll.direction & (1 << LIBINPUT_POINTER_AXIS_HORIZONTAL_SCROLL))) {
 501                 pointer_notify_axis(&tp->device->base,
 502                                     time,
 503                                     LIBINPUT_POINTER_AXIS_HORIZONTAL_SCROLL,
 504                                     li_fixed_from_double(dx));
 505         }
 506 }
 507
 508 static int
 509 tp_post_scroll_events(struct tp_dispatch *tp, uint32_t time)
 510 {
 511         /* don't scroll if a clickpad is held down */
 512         if (!tp->buttons.has_buttons &&
 513             (tp->buttons.state || tp->buttons.old_state))
 514                 return 0;
 515
 516         if (tp->nfingers_down != 2) {
 517                 /* terminate scrolling with a zero scroll event to notify
 518                  * caller that it really ended now */
 519                 if (tp->scroll.state != SCROLL_STATE_NONE) {
 520                         tp->scroll.state = SCROLL_STATE_NONE;
 521                         tp->scroll.direction = 0;
 522                         if (tp->scroll.direction & LIBINPUT_POINTER_AXIS_VERTICAL_SCROLL)
 523                                 pointer_notify_axis(&tp->device->base,
 524                                                     time,
 525                                                     LIBINPUT_POINTER_AXIS_VERTICAL_SCROLL,
 526                                                     0);
 527                         if (tp->scroll.direction & LIBINPUT_POINTER_AXIS_HORIZONTAL_SCROLL)
 528                                 pointer_notify_axis(&tp->device->base,
 529                                                     time,
 530                                                     LIBINPUT_POINTER_AXIS_HORIZONTAL_SCROLL,
 531                                                     0);
 532                 }
 533         } else {
 534                 tp_post_twofinger_scroll(tp, time);
 535                 return 1;
 536         }
 537         return 0;
 538 }
 539
 540 static int
 541 tp_post_clickfinger_buttons(struct tp_dispatch *tp, uint32_t time)
 542 {
 543         uint32_t current, old, button;
 544         enum libinput_pointer_button_state state;
 545
 546         current = tp->buttons.state;
 547         old = tp->buttons.old_state;
 548
 549         if (current == old)
 550                 return 0;
 551
 552         switch (tp->nfingers_down) {
 553                 case 1: button = BTN_LEFT; break;
 554                 case 2: button = BTN_RIGHT; break;
 555                 case 3: button = BTN_MIDDLE; break;
 556                 default:
 557                         return 0;
 558         }
 559
 560         if (current)
 561                 state = LIBINPUT_POINTER_BUTTON_STATE_PRESSED;
 562         else
 563                 state = LIBINPUT_POINTER_BUTTON_STATE_RELEASED;
 564
 565         pointer_notify_button(&tp->device->base,
 566                               time,
 567                               button,
 568                               state);
 569         return 1;
 570 }
 571
 572 static int
 573 tp_post_physical_buttons(struct tp_dispatch *tp, uint32_t time)
 574 {
 575         uint32_t current, old, button;
 576
 577         current = tp->buttons.state;
 578         old = tp->buttons.old_state;
 579         button = BTN_LEFT;
 580
 581         while (current || old) {
 582                 enum libinput_pointer_button_state state;
 583
 584                 if ((current & 0x1) ^ (old & 0x1)) {
 585                         if (!!(current & 0x1))
 586                                 state = LIBINPUT_POINTER_BUTTON_STATE_PRESSED;
 587                         else
 588                                 state = LIBINPUT_POINTER_BUTTON_STATE_RELEASED;
 589
 590                         pointer_notify_button(&tp->device->base,
 591                                               time,
 592                                               button,
 593                                               state);
 594                 }
 595
 596                 button++;
 597                 current >>= 1;
 598                 old >>= 1;
 599         }
 600
 601         return 0;
 602 }
 603
 604 static int
 605 tp_post_button_events(struct tp_dispatch *tp, uint32_t time)
 606 {
 607         int rc;
 608
 609         if ((tp->queued &
 610                 (TOUCHPAD_EVENT_BUTTON_PRESS|TOUCHPAD_EVENT_BUTTON_RELEASE)) == 0)
 611                                 return 0;
 612
 613         if (tp->buttons.has_buttons)
 614                 rc = tp_post_physical_buttons(tp, time);
 615         else
 616                 rc = tp_post_clickfinger_buttons(tp, time);
 617
 618         return rc;
 619 }
 620
 621 static void
 622 tp_post_events(struct tp_dispatch *tp, uint32_t time)
 623 {
 624         struct tp_touch *t = tp_current_touch(tp);
 625         double dx, dy;
 626
 627         if (tp_post_button_events(tp, time) != 0)
 628                 return;
 629
 630         if (tp_tap_handle_state(tp, time) != 0)
 631                 return;
 632
 633         if (tp_post_scroll_events(tp, time) != 0)
 634                 return;
 635
 636         if (t->history.count >= TOUCHPAD_MIN_SAMPLES) {
 637                 if (!t->is_pointer) {
 638                         tp_for_each_touch(tp, t) {
 639                                 if (t->is_pointer)
 640                                         break;
 641                         }
 642                 }
 643
 644                 if (!t->is_pointer)
 645                         return;
 646
 647                 tp_get_delta(t, &dx, &dy);
 648                 tp_filter_motion(tp, &dx, &dy, time);
 649
 650                 if (dx != 0 || dy != 0)
 651                         pointer_notify_motion(
 652                                 &tp->device->base,
 653                                 time,
 654                                 li_fixed_from_double(dx),
 655                                 li_fixed_from_double(dy));
 656         }
 657 }
 658
 659 static void
 660 tp_process(struct evdev_dispatch *dispatch,
 661            struct evdev_device *device,
 662            struct input_event *e,
 663            uint32_t time)
 664 {
 665         struct tp_dispatch *tp =
 666                 (struct tp_dispatch *)dispatch;
 667
 668         switch (e->type) {
 669         case EV_ABS:
 670                 if (tp->has_mt)
 671                         tp_process_absolute(tp, e, time);
 672                 else
 673                         tp_process_absolute_st(tp, e, time);
 674                 break;
 675         case EV_KEY:
 676                 tp_process_key(tp, e, time);
 677                 break;
 678         case EV_SYN:
 679                 tp_process_state(tp, time);
 680                 tp_post_events(tp, time);
 681                 tp_post_process_state(tp, time);
 682                 break;
 683         }
 684 }
 685
 686 static void
 687 tp_destroy(struct evdev_dispatch *dispatch)
 688 {
 689         struct tp_dispatch *tp =
 690                 (struct tp_dispatch*)dispatch;
 691
 692         if (tp->filter)
 693                 tp->filter->interface->destroy(tp->filter);
 694         free(tp->touches);
 695         free(tp);
 696 }
 697
 698 static struct evdev_dispatch_interface tp_interface = {
 699         tp_process,
 700         tp_destroy
 701 };
 702
 703 static int
 704 tp_init_slots(struct tp_dispatch *tp,
 705               struct evdev_device *device)
 706 {
 707         const struct input_absinfo *absinfo;
 708
 709         absinfo = libevdev_get_abs_info(device->evdev, ABS_MT_SLOT);
 710         if (absinfo) {
 711                 tp->ntouches = absinfo->maximum + 1;
 712                 tp->slot = absinfo->value;
 713                 tp->has_mt = true;
 714         } else {
 715                 tp->ntouches = 5; /* FIXME: based on DOUBLETAP, etc. */
 716                 tp->slot = 0;
 717                 tp->has_mt = false;
 718         }
 719         tp->touches = calloc(tp->ntouches,
 720                              sizeof(struct tp_touch));
 721
 722         return 0;
 723 }
 724
 725 static int
 726 tp_init_accel(struct tp_dispatch *touchpad, double diagonal)
 727 {
 728         struct motion_filter *accel;
 729
 730         touchpad->accel.constant_factor =
 731                 DEFAULT_CONSTANT_ACCEL_NUMERATOR / diagonal;
 732         touchpad->accel.min_factor = DEFAULT_MIN_ACCEL_FACTOR;
 733         touchpad->accel.max_factor = DEFAULT_MAX_ACCEL_FACTOR;
 734
 735         accel = create_pointer_accelator_filter(tp_accel_profile);
 736         if (accel == NULL)
 737                 return -1;
 738
 739         touchpad->filter = accel;
 740
 741         return 0;
 742 }
 743
 744 static int
 745 tp_init_scroll(struct tp_dispatch *tp)
 746 {
 747         tp->scroll.direction = 0;
 748         tp->scroll.state = SCROLL_STATE_NONE;
 749
 750         return 0;
 751 }
 752
 753 static int
 754 tp_init(struct tp_dispatch *tp,
 755         struct evdev_device *device)
 756 {
 757         int width, height;
 758         double diagonal;
 759
 760         tp->base.interface = &tp_interface;
 761         tp->device = device;
 762
 763         if (tp_init_slots(tp, device) != 0)
 764                 return -1;
 765
 766         width = abs(device->abs.max_x - device->abs.min_x);
 767         height = abs(device->abs.max_y - device->abs.min_y);
 768         diagonal = sqrt(width*width + height*height);
 769
 770         tp->hysteresis.margin_x =
 771                 diagonal / DEFAULT_HYSTERESIS_MARGIN_DENOMINATOR;
 772         tp->hysteresis.margin_y =
 773                 diagonal / DEFAULT_HYSTERESIS_MARGIN_DENOMINATOR;
 774
 775         if (libevdev_has_event_code(device->evdev, EV_KEY, BTN_MIDDLE) ||
 776             libevdev_has_event_code(device->evdev, EV_KEY, BTN_RIGHT))
 777                 tp->buttons.has_buttons = true;
 778
 779         if (tp_init_scroll(tp) != 0)
 780                 return -1;
 781
 782         if (tp_init_accel(tp, diagonal) != 0)
 783                 return -1;
 784
 785         if (tp_init_tap(tp) != 0)
 786                 return -1;
 787
 788         return 0;
 789 }
 790
 791 struct evdev_dispatch *
 792 evdev_mt_touchpad_create(struct evdev_device *device)
 793 {
 794         struct tp_dispatch *tp;
 795
 796         tp = zalloc(sizeof *tp);
 797         if (!tp)
 798                 return NULL;
 799
 800         if (tp_init(tp, device) != 0) {
 801                 tp_destroy(&tp->base);
 802                 return NULL;
 803         }
 804
 805         return  &tp->base;
 806 }