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_ACCEL_NUMERATOR 1200.0
  32 #define DEFAULT_HYSTERESIS_MARGIN_DENOMINATOR 700.0
  33
  34 static inline int
  35 tp_hysteresis(int in, int center, int margin)
  36 {
  37         int diff = in - center;
  38         if (abs(diff) <= margin)
  39                 return center;
  40
  41         if (diff > margin)
  42                 return center + diff - margin;
  43         else
  44                 return center + diff + margin;
  45 }
  46
  47 static inline struct tp_motion *
  48 tp_motion_history_offset(struct tp_touch *t, int offset)
  49 {
  50         int offset_index =
  51                 (t->history.index - offset + TOUCHPAD_HISTORY_LENGTH) %
  52                 TOUCHPAD_HISTORY_LENGTH;
  53
  54         return &t->history.samples[offset_index];
  55 }
  56
  57 static void
  58 tp_filter_motion(struct tp_dispatch *tp,
  59                  double *dx, double *dy, uint64_t time)
  60 {
  61         struct motion_params motion;
  62
  63         motion.dx = *dx * tp->accel.x_scale_coeff;
  64         motion.dy = *dy * tp->accel.y_scale_coeff;
  65
  66         if (motion.dx != 0.0 || motion.dy != 0.0)
  67                 filter_dispatch(tp->filter, &motion, tp, time);
  68
  69         *dx = motion.dx;
  70         *dy = motion.dy;
  71 }
  72
  73 static inline void
  74 tp_motion_history_push(struct tp_touch *t)
  75 {
  76         int motion_index = (t->history.index + 1) % TOUCHPAD_HISTORY_LENGTH;
  77
  78         if (t->history.count < TOUCHPAD_HISTORY_LENGTH)
  79                 t->history.count++;
  80
  81         t->history.samples[motion_index].x = t->x;
  82         t->history.samples[motion_index].y = t->y;
  83         t->history.index = motion_index;
  84 }
  85
  86 static inline void
  87 tp_motion_hysteresis(struct tp_dispatch *tp,
  88                      struct tp_touch *t)
  89 {
  90         int x = t->x,
  91             y = t->y;
  92
  93         if (t->history.count == 0) {
  94                 t->hysteresis.center_x = t->x;
  95                 t->hysteresis.center_y = t->y;
  96         } else {
  97                 x = tp_hysteresis(x,
  98                                   t->hysteresis.center_x,
  99                                   tp->hysteresis.margin_x);
 100                 y = tp_hysteresis(y,
 101                                   t->hysteresis.center_y,
 102                                   tp->hysteresis.margin_y);
 103                 t->hysteresis.center_x = x;
 104                 t->hysteresis.center_y = y;
 105                 t->x = x;
 106                 t->y = y;
 107         }
 108 }
 109
 110 static inline void
 111 tp_motion_history_reset(struct tp_touch *t)
 112 {
 113         t->history.count = 0;
 114 }
 115
 116 static inline struct tp_touch *
 117 tp_current_touch(struct tp_dispatch *tp)
 118 {
 119         return &tp->touches[min(tp->slot, tp->ntouches - 1)];
 120 }
 121
 122 static inline struct tp_touch *
 123 tp_get_touch(struct tp_dispatch *tp, unsigned int slot)
 124 {
 125         assert(slot < tp->ntouches);
 126         return &tp->touches[slot];
 127 }
 128
 129 static inline void
 130 tp_begin_touch(struct tp_dispatch *tp, struct tp_touch *t)
 131 {
 132         if (t->state != TOUCH_UPDATE) {
 133                 tp_motion_history_reset(t);
 134                 t->dirty = true;
 135                 t->state = TOUCH_BEGIN;
 136                 t->pinned.is_pinned = false;
 137                 tp->nfingers_down++;
 138                 assert(tp->nfingers_down >= 1);
 139                 tp->queued |= TOUCHPAD_EVENT_MOTION;
 140         }
 141 }
 142
 143 static inline void
 144 tp_end_touch(struct tp_dispatch *tp, struct tp_touch *t)
 145 {
 146         if (t->state == TOUCH_NONE)
 147                 return;
 148
 149         t->dirty = true;
 150         t->is_pointer = false;
 151         t->state = TOUCH_END;
 152         t->pinned.is_pinned = false;
 153         assert(tp->nfingers_down >= 1);
 154         tp->nfingers_down--;
 155         tp->queued |= TOUCHPAD_EVENT_MOTION;
 156 }
 157
 158 static double
 159 tp_estimate_delta(int x0, int x1, int x2, int x3)
 160 {
 161         return (x0 + x1 - x2 - x3) / 4;
 162 }
 163
 164 void
 165 tp_get_delta(struct tp_touch *t, double *dx, double *dy)
 166 {
 167         if (t->history.count < 4) {
 168                 *dx = 0;
 169                 *dy = 0;
 170                 return;
 171         }
 172
 173         *dx = tp_estimate_delta(tp_motion_history_offset(t, 0)->x,
 174                                 tp_motion_history_offset(t, 1)->x,
 175                                 tp_motion_history_offset(t, 2)->x,
 176                                 tp_motion_history_offset(t, 3)->x);
 177         *dy = tp_estimate_delta(tp_motion_history_offset(t, 0)->y,
 178                                 tp_motion_history_offset(t, 1)->y,
 179                                 tp_motion_history_offset(t, 2)->y,
 180                                 tp_motion_history_offset(t, 3)->y);
 181 }
 182
 183 static void
 184 tp_process_absolute(struct tp_dispatch *tp,
 185                     const struct input_event *e,
 186                     uint64_t time)
 187 {
 188         struct tp_touch *t = tp_current_touch(tp);
 189
 190         switch(e->code) {
 191         case ABS_MT_POSITION_X:
 192                 t->x = e->value;
 193                 t->millis = time;
 194                 t->dirty = true;
 195                 tp->queued |= TOUCHPAD_EVENT_MOTION;
 196                 break;
 197         case ABS_MT_POSITION_Y:
 198                 t->y = e->value;
 199                 t->millis = time;
 200                 t->dirty = true;
 201                 tp->queued |= TOUCHPAD_EVENT_MOTION;
 202                 break;
 203         case ABS_MT_SLOT:
 204                 tp->slot = e->value;
 205                 break;
 206         case ABS_MT_TRACKING_ID:
 207                 t->millis = time;
 208                 if (e->value != -1)
 209                         tp_begin_touch(tp, t);
 210                 else
 211                         tp_end_touch(tp, t);
 212         }
 213 }
 214
 215 static void
 216 tp_process_absolute_st(struct tp_dispatch *tp,
 217                        const struct input_event *e,
 218                        uint64_t time)
 219 {
 220         struct tp_touch *t = tp_current_touch(tp);
 221
 222         switch(e->code) {
 223         case ABS_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_Y:
 230                 t->y = e->value;
 231                 t->millis = time;
 232                 t->dirty = true;
 233                 tp->queued |= TOUCHPAD_EVENT_MOTION;
 234                 break;
 235         }
 236 }
 237
 238 static void
 239 tp_process_fake_touch(struct tp_dispatch *tp,
 240                       const struct input_event *e,
 241                       uint64_t time)
 242 {
 243         struct tp_touch *t;
 244         unsigned int fake_touches;
 245         unsigned int nfake_touches;
 246         unsigned int i;
 247         unsigned int shift;
 248
 249         if (e->code != BTN_TOUCH &&
 250             (e->code < BTN_TOOL_DOUBLETAP || e->code > BTN_TOOL_QUADTAP))
 251                 return;
 252
 253         shift = e->code == BTN_TOUCH ? 0 : (e->code - BTN_TOOL_DOUBLETAP + 1);
 254
 255         if (e->value)
 256                 tp->fake_touches |= 1 << shift;
 257         else
 258                 tp->fake_touches &= ~(0x1 << shift);
 259
 260         fake_touches = tp->fake_touches;
 261         nfake_touches = 0;
 262         while (fake_touches) {
 263                 nfake_touches++;
 264                 fake_touches >>= 1;
 265         }
 266
 267         for (i = 0; i < tp->ntouches; i++) {
 268                 t = tp_get_touch(tp, i);
 269                 if (i >= nfake_touches) {
 270                         if (t->state != TOUCH_NONE) {
 271                                 tp_end_touch(tp, t);
 272                                 t->millis = time;
 273                         }
 274                 } else if (t->state != TOUCH_UPDATE &&
 275                            t->state != TOUCH_BEGIN) {
 276                         t->state = TOUCH_NONE;
 277                         tp_begin_touch(tp, t);
 278                         t->millis = time;
 279                         t->fake =true;
 280                 }
 281         }
 282
 283         assert(tp->nfingers_down == nfake_touches);
 284 }
 285
 286 static void
 287 tp_process_key(struct tp_dispatch *tp,
 288                const struct input_event *e,
 289                uint64_t time)
 290 {
 291         switch (e->code) {
 292                 case BTN_LEFT:
 293                 case BTN_MIDDLE:
 294                 case BTN_RIGHT:
 295                         tp_process_button(tp, e, time);
 296                         break;
 297                 case BTN_TOUCH:
 298                 case BTN_TOOL_DOUBLETAP:
 299                 case BTN_TOOL_TRIPLETAP:
 300                 case BTN_TOOL_QUADTAP:
 301                         if (!tp->has_mt)
 302                                 tp_process_fake_touch(tp, e, time);
 303                         break;
 304         }
 305 }
 306
 307 static void
 308 tp_unpin_finger(struct tp_dispatch *tp, struct tp_touch *t)
 309 {
 310         unsigned int xdist, ydist;
 311
 312         if (!t->pinned.is_pinned)
 313                 return;
 314
 315         xdist = abs(t->x - t->pinned.center_x);
 316         ydist = abs(t->y - t->pinned.center_y);
 317
 318         if (xdist * xdist + ydist * ydist >=
 319                         tp->buttons.motion_dist * tp->buttons.motion_dist) {
 320                 t->pinned.is_pinned = false;
 321                 tp_set_pointer(tp, t);
 322         }
 323 }
 324
 325 static void
 326 tp_pin_fingers(struct tp_dispatch *tp)
 327 {
 328         struct tp_touch *t;
 329
 330         tp_for_each_touch(tp, t) {
 331                 t->is_pointer = false;
 332                 t->pinned.is_pinned = true;
 333                 t->pinned.center_x = t->x;
 334                 t->pinned.center_y = t->y;
 335         }
 336 }
 337
 338 static int
 339 tp_touch_active(struct tp_dispatch *tp, struct tp_touch *t)
 340 {
 341         return (t->state == TOUCH_BEGIN || t->state == TOUCH_UPDATE) &&
 342                 !t->pinned.is_pinned && tp_button_touch_active(tp, t);
 343 }
 344
 345 void
 346 tp_set_pointer(struct tp_dispatch *tp, struct tp_touch *t)
 347 {
 348         struct tp_touch *tmp = NULL;
 349
 350         /* Only set the touch as pointer if we don't have one yet */
 351         tp_for_each_touch(tp, tmp) {
 352                 if (tmp->is_pointer)
 353                         return;
 354         }
 355
 356         if (tp_touch_active(tp, t))
 357                 t->is_pointer = true;
 358 }
 359
 360 static void
 361 tp_process_state(struct tp_dispatch *tp, uint64_t time)
 362 {
 363         struct tp_touch *t;
 364         struct tp_touch *first = tp_get_touch(tp, 0);
 365
 366         tp_for_each_touch(tp, t) {
 367                 if (!tp->has_mt && t != first && first->fake) {
 368                         t->x = first->x;
 369                         t->y = first->y;
 370                         if (!t->dirty)
 371                                 t->dirty = first->dirty;
 372                 } else if (!t->dirty)
 373                         continue;
 374
 375                 tp_motion_hysteresis(tp, t);
 376                 tp_motion_history_push(t);
 377
 378                 tp_unpin_finger(tp, t);
 379         }
 380
 381         tp_button_handle_state(tp, time);
 382
 383         /*
 384          * We have a physical button down event on a clickpad. To avoid
 385          * spurious pointer moves by the clicking finger we pin all fingers.
 386          * We unpin fingers when they move more then a certain threshold to
 387          * to allow drag and drop.
 388          */
 389         if ((tp->queued & TOUCHPAD_EVENT_BUTTON_PRESS) &&
 390             tp->buttons.is_clickpad)
 391                 tp_pin_fingers(tp);
 392 }
 393
 394 static void
 395 tp_post_process_state(struct tp_dispatch *tp, uint64_t time)
 396 {
 397         struct tp_touch *t;
 398
 399         tp_for_each_touch(tp, t) {
 400                 if (!t->dirty)
 401                         continue;
 402
 403                 if (t->state == TOUCH_END) {
 404                         t->state = TOUCH_NONE;
 405                         t->fake = false;
 406                 } else if (t->state == TOUCH_BEGIN)
 407                         t->state = TOUCH_UPDATE;
 408
 409                 t->dirty = false;
 410         }
 411
 412         tp->buttons.old_state = tp->buttons.state;
 413
 414         tp->queued = TOUCHPAD_EVENT_NONE;
 415 }
 416
 417 static void
 418 tp_post_twofinger_scroll(struct tp_dispatch *tp, uint64_t time)
 419 {
 420         struct tp_touch *t;
 421         int nchanged = 0;
 422         double dx = 0, dy =0;
 423         double tmpx, tmpy;
 424
 425         tp_for_each_touch(tp, t) {
 426                 if (tp_touch_active(tp, t) && t->dirty) {
 427                         nchanged++;
 428                         tp_get_delta(t, &tmpx, &tmpy);
 429
 430                         dx += tmpx;
 431                         dy += tmpy;
 432                 }
 433                 /* Stop spurious MOTION events at the end of scrolling */
 434                 t->is_pointer = false;
 435         }
 436
 437         if (nchanged == 0)
 438                 return;
 439
 440         dx /= nchanged;
 441         dy /= nchanged;
 442
 443         tp_filter_motion(tp, &dx, &dy, time);
 444
 445         /* Require at least five px scrolling to start */
 446         if (dy <= -5.0 || dy >= 5.0)
 447                 tp->scroll.direction |= (1 << LIBINPUT_POINTER_AXIS_SCROLL_VERTICAL);
 448
 449         if (dx <= -5.0 || dx >= 5.0)
 450                 tp->scroll.direction |= (1 << LIBINPUT_POINTER_AXIS_SCROLL_HORIZONTAL);
 451
 452         if (dy != 0.0 &&
 453             (tp->scroll.direction & (1 << LIBINPUT_POINTER_AXIS_SCROLL_VERTICAL))) {
 454                 pointer_notify_axis(&tp->device->base,
 455                                     time,
 456                                     LIBINPUT_POINTER_AXIS_SCROLL_VERTICAL,
 457                                     dy);
 458         }
 459
 460         if (dx != 0.0 &&
 461             (tp->scroll.direction & (1 << LIBINPUT_POINTER_AXIS_SCROLL_HORIZONTAL))) {
 462                 pointer_notify_axis(&tp->device->base,
 463                                     time,
 464                                     LIBINPUT_POINTER_AXIS_SCROLL_HORIZONTAL,
 465                                     dx);
 466         }
 467 }
 468
 469 static void
 470 tp_stop_scroll_events(struct tp_dispatch *tp, uint64_t time)
 471 {
 472         /* terminate scrolling with a zero scroll event */
 473         if (tp->scroll.direction & (1 << LIBINPUT_POINTER_AXIS_SCROLL_VERTICAL))
 474                 pointer_notify_axis(&tp->device->base,
 475                                     time,
 476                                     LIBINPUT_POINTER_AXIS_SCROLL_VERTICAL,
 477                                     0);
 478         if (tp->scroll.direction & (1 << LIBINPUT_POINTER_AXIS_SCROLL_HORIZONTAL))
 479                 pointer_notify_axis(&tp->device->base,
 480                                     time,
 481                                     LIBINPUT_POINTER_AXIS_SCROLL_HORIZONTAL,
 482                                     0);
 483
 484         tp->scroll.direction = 0;
 485 }
 486
 487 static int
 488 tp_post_scroll_events(struct tp_dispatch *tp, uint64_t time)
 489 {
 490         struct tp_touch *t;
 491         int nfingers_down = 0;
 492
 493         /* Only count active touches for 2 finger scrolling */
 494         tp_for_each_touch(tp, t) {
 495                 if (tp_touch_active(tp, t))
 496                         nfingers_down++;
 497         }
 498
 499         if (nfingers_down != 2) {
 500                 tp_stop_scroll_events(tp, time);
 501                 return 0;
 502         }
 503
 504         tp_post_twofinger_scroll(tp, time);
 505         return 1;
 506 }
 507
 508 static void
 509 tp_post_events(struct tp_dispatch *tp, uint64_t time)
 510 {
 511         struct tp_touch *t = tp_current_touch(tp);
 512         double dx, dy;
 513         int consumed = 0;
 514
 515         consumed |= tp_tap_handle_state(tp, time);
 516         consumed |= tp_post_button_events(tp, time);
 517
 518         if (consumed) {
 519                 tp_stop_scroll_events(tp, time);
 520                 return;
 521         }
 522
 523         if (tp_post_scroll_events(tp, time) != 0)
 524                 return;
 525
 526         if (t->history.count >= TOUCHPAD_MIN_SAMPLES) {
 527                 if (!t->is_pointer) {
 528                         tp_for_each_touch(tp, t) {
 529                                 if (t->is_pointer)
 530                                         break;
 531                         }
 532                 }
 533
 534                 if (!t->is_pointer)
 535                         return;
 536
 537                 tp_get_delta(t, &dx, &dy);
 538                 tp_filter_motion(tp, &dx, &dy, time);
 539
 540                 if (dx != 0.0 || dy != 0.0)
 541                         pointer_notify_motion(&tp->device->base, time, dx, dy);
 542         }
 543 }
 544
 545 static void
 546 tp_process(struct evdev_dispatch *dispatch,
 547            struct evdev_device *device,
 548            struct input_event *e,
 549            uint64_t time)
 550 {
 551         struct tp_dispatch *tp =
 552                 (struct tp_dispatch *)dispatch;
 553
 554         switch (e->type) {
 555         case EV_ABS:
 556                 if (tp->has_mt)
 557                         tp_process_absolute(tp, e, time);
 558                 else
 559                         tp_process_absolute_st(tp, e, time);
 560                 break;
 561         case EV_KEY:
 562                 tp_process_key(tp, e, time);
 563                 break;
 564         case EV_SYN:
 565                 tp_process_state(tp, time);
 566                 tp_post_events(tp, time);
 567                 tp_post_process_state(tp, time);
 568                 break;
 569         }
 570 }
 571
 572 static void
 573 tp_destroy(struct evdev_dispatch *dispatch)
 574 {
 575         struct tp_dispatch *tp =
 576                 (struct tp_dispatch*)dispatch;
 577
 578         tp_destroy_tap(tp);
 579         tp_destroy_buttons(tp);
 580
 581         filter_destroy(tp->filter);
 582         free(tp->touches);
 583         free(tp);
 584 }
 585
 586 static struct evdev_dispatch_interface tp_interface = {
 587         tp_process,
 588         tp_destroy
 589 };
 590
 591 static void
 592 tp_init_touch(struct tp_dispatch *tp,
 593               struct tp_touch *t)
 594 {
 595         t->tp = tp;
 596 }
 597
 598 static int
 599 tp_init_slots(struct tp_dispatch *tp,
 600               struct evdev_device *device)
 601 {
 602         size_t i;
 603         const struct input_absinfo *absinfo;
 604
 605         absinfo = libevdev_get_abs_info(device->evdev, ABS_MT_SLOT);
 606         if (absinfo) {
 607                 tp->ntouches = absinfo->maximum + 1;
 608                 tp->slot = absinfo->value;
 609                 tp->has_mt = true;
 610         } else {
 611                 struct map {
 612                         unsigned int code;
 613                         int ntouches;
 614                 } max_touches[] = {
 615                         { BTN_TOOL_QUINTTAP, 5 },
 616                         { BTN_TOOL_QUADTAP, 4 },
 617                         { BTN_TOOL_TRIPLETAP, 3 },
 618                         { BTN_TOOL_DOUBLETAP, 2 },
 619                 };
 620                 struct map *m;
 621
 622                 tp->slot = 0;
 623                 tp->has_mt = false;
 624                 tp->ntouches = 1;
 625
 626                 ARRAY_FOR_EACH(max_touches, m) {
 627                         if (libevdev_has_event_code(device->evdev,
 628                                                     EV_KEY,
 629                                                     m->code)) {
 630                                 tp->ntouches = m->ntouches;
 631                                 break;
 632                         }
 633                 }
 634         }
 635         tp->touches = calloc(tp->ntouches,
 636                              sizeof(struct tp_touch));
 637         if (!tp->touches)
 638                 return -1;
 639
 640         for (i = 0; i < tp->ntouches; i++)
 641                 tp_init_touch(tp, &tp->touches[i]);
 642
 643         return 0;
 644 }
 645
 646 static int
 647 tp_init_accel(struct tp_dispatch *tp, double diagonal)
 648 {
 649         struct motion_filter *accel;
 650         int res_x, res_y;
 651
 652         if (tp->has_mt) {
 653                 res_x = libevdev_get_abs_resolution(tp->device->evdev,
 654                                                     ABS_MT_POSITION_X);
 655                 res_y = libevdev_get_abs_resolution(tp->device->evdev,
 656                                                     ABS_MT_POSITION_Y);
 657         } else {
 658                 res_x = libevdev_get_abs_resolution(tp->device->evdev,
 659                                                     ABS_X);
 660                 res_y = libevdev_get_abs_resolution(tp->device->evdev,
 661                                                     ABS_Y);
 662         }
 663
 664         /*
 665          * Not all touchpads report the same amount of units/mm (resolution).
 666          * Normalize motion events to a resolution of 15.74 units/mm
 667          * (== 400 dpi) as base (unaccelerated) speed. This also evens out any
 668          * differences in x and y resolution, so that a circle on the
 669          * touchpad does not turn into an elipse on the screen.
 670          *
 671          * We pick 400dpi as thats one of the many default resolutions
 672          * for USB mice, so we end up with a similar base speed on the device.
 673          */
 674         if (res_x > 1 && res_y > 1) {
 675                 tp->accel.x_scale_coeff = (400/25.4) / res_x;
 676                 tp->accel.y_scale_coeff = (400/25.4) / res_y;
 677         } else {
 678         /*
 679          * For touchpads where the driver does not provide resolution, fall
 680          * back to scaling motion events based on the diagonal size in units.
 681          */
 682                 tp->accel.x_scale_coeff = DEFAULT_ACCEL_NUMERATOR / diagonal;
 683                 tp->accel.y_scale_coeff = DEFAULT_ACCEL_NUMERATOR / diagonal;
 684         }
 685
 686         accel = create_pointer_accelator_filter(
 687                         pointer_accel_profile_smooth_simple);
 688         if (accel == NULL)
 689                 return -1;
 690
 691         tp->filter = accel;
 692
 693         return 0;
 694 }
 695
 696 static int
 697 tp_init_scroll(struct tp_dispatch *tp)
 698 {
 699         tp->scroll.direction = 0;
 700
 701         return 0;
 702 }
 703
 704 static int
 705 tp_init(struct tp_dispatch *tp,
 706         struct evdev_device *device)
 707 {
 708         int width, height;
 709         double diagonal;
 710
 711         tp->base.interface = &tp_interface;
 712         tp->device = device;
 713
 714         if (tp_init_slots(tp, device) != 0)
 715                 return -1;
 716
 717         width = abs(device->abs.absinfo_x->maximum -
 718                     device->abs.absinfo_x->minimum);
 719         height = abs(device->abs.absinfo_y->maximum -
 720                      device->abs.absinfo_y->minimum);
 721         diagonal = sqrt(width*width + height*height);
 722
 723         tp->hysteresis.margin_x =
 724                 diagonal / DEFAULT_HYSTERESIS_MARGIN_DENOMINATOR;
 725         tp->hysteresis.margin_y =
 726                 diagonal / DEFAULT_HYSTERESIS_MARGIN_DENOMINATOR;
 727
 728         if (tp_init_scroll(tp) != 0)
 729                 return -1;
 730
 731         if (tp_init_accel(tp, diagonal) != 0)
 732                 return -1;
 733
 734         if (tp_init_tap(tp) != 0)
 735                 return -1;
 736
 737         if (tp_init_buttons(tp, device) != 0)
 738                 return -1;
 739
 740         return 0;
 741 }
 742
 743 struct evdev_dispatch *
 744 evdev_mt_touchpad_create(struct evdev_device *device)
 745 {
 746         struct tp_dispatch *tp;
 747
 748         tp = zalloc(sizeof *tp);
 749         if (!tp)
 750                 return NULL;
 751
 752         if (tp_init(tp, device) != 0) {
 753                 tp_destroy(&tp->base);
 754                 return NULL;
 755         }
 756
 757         return  &tp->base;
 758 }