Revert of Port Chromium OS touch noise filtering to Chromium

ui/events/ozone/evdev/touch_noise/single_position_touch_noise_filter.cc

-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "ui/events/ozone/evdev/touch_noise/single_position_touch_noise_filter.h"
-
-#include "base/logging.h"
-#include "base/strings/stringprintf.h"
-
-namespace ui {
-
-namespace {
-
-// Max squared distance between fingers for the fingers to be considered in the
-// same position.
-const int kSamePositionMaxDistance2 = 2 * 2;
-
-// Max squared movement of a finger before it's no longer considered noise.
-const int kNoiseMaxMovement2 = 2 * 2;
-
-// Min duration in milliseconds after which touches in the same position are
-// considered noise.
-const int kMinDurationMs = 2000;
-
-// Max duration in milliseconds to check for common positions with previous
-// touches.
-const int kMaxDurationMs = 4000;
-
-// Returns the squared distance between (|x1|, |y1|) and (|x2|, |y2|)
-int Distance2(int x1, int y1, int x2, int y2) {
-  int offset_x = x2 - x1;
-  int offset_y = y2 - y1;
-  return offset_x * offset_x + offset_y * offset_y;
-}
-
-}  // namespace
-
-SinglePositionTouchNoiseFilter::SinglePositionTouchNoiseFilter()
-    : tracked_touches_start_(0), tracked_touches_end_(0) {
-  for (size_t i = 0; i < kNumTouchEvdevSlots; ++i)
-    tracked_slots_[i] = kNumTrackedTouches;
-}
-
-void SinglePositionTouchNoiseFilter::Filter(
-    const std::vector<InProgressTouchEvdev>& touches,
-    base::TimeDelta time,
-    std::bitset<kNumTouchEvdevSlots>* slots_with_noise) {
-  // Forget old touches which will no longer be considered for overlap.
-  base::TimeDelta touch_cutoff =
-      time - base::TimeDelta::FromMilliseconds(kMaxDurationMs);
-  for (size_t i = tracked_touches_start_; i != tracked_touches_end_;
-       i = (i + 1) % kNumTrackedTouches) {
-    if (!tracked_touches_[i].valid)
-      continue;
-    if (tracked_touches_[i].end < touch_cutoff)
-      StopTrackingTouch(i);
-  }
-
-  for (const InProgressTouchEvdev& touch : touches) {
-    size_t slot = touch.slot;
-
-    bool arrived = touch.touching && !touch.was_touching;
-    bool departed = !touch.touching && touch.was_touching;
-    if (departed)
-      tracked_slots_[slot] = kNumTrackedTouches;
-    if (!touch.touching)
-      continue;
-
-    // Track all new touches until they move too far.
-    if (arrived)
-      TrackTouch(touch, time);
-
-    size_t t_ind = tracked_slots_[slot];
-    if (t_ind != kNumTrackedTouches) {
-      tracked_touches_[t_ind].end = time;
-      // Stop tracking if touch moves more than sqrt(kNoiseMaxMovement2).
-      if (Distance2(touch.x, touch.y, tracked_touches_[t_ind].x,
-                    tracked_touches_[t_ind].y) > kNoiseMaxMovement2) {
-        StopTrackingTouch(t_ind);
-      } else {
-        // Determine duration over which touches have been occuring in this
-        // position.
-        base::TimeDelta max_duration;
-        for (size_t i = tracked_touches_start_; i != tracked_touches_end_;
-             i = (i + 1) % kNumTrackedTouches) {
-          TrackedTouch* tracked_touch = &tracked_touches_[i];
-          if (!tracked_touch->valid)
-            continue;
-          if (Distance2(touch.x, touch.y, tracked_touch->x, tracked_touch->y) <=
-              kSamePositionMaxDistance2) {
-            base::TimeDelta duration = time - tracked_touch->begin;
-            if (duration > max_duration)
-              max_duration = duration;
-          }
-        }
-
-        if (max_duration.InMilliseconds() > kMinDurationMs) {
-          VLOG(2) << base::StringPrintf(
-              "Cancel tracking id %d, in position occurring for %ldms",
-              touch.tracking_id, max_duration.InMilliseconds());
-          slots_with_noise->set(slot);
-        }
-      }
-    }
-  }
-}
-
-void SinglePositionTouchNoiseFilter::StopTrackingTouch(size_t index) {
-  size_t slot = tracked_touches_[index].slot;
-  if (tracked_slots_[slot] == index)
-    tracked_slots_[slot] = kNumTrackedTouches;
-  tracked_touches_[index].valid = false;
-
-  // If first touch is canceled, remove all dead touches.
-  if (index == tracked_touches_start_) {
-    while (!tracked_touches_[tracked_touches_start_].valid &&
-           tracked_touches_start_ != tracked_touches_end_) {
-      tracked_touches_start_ =
-          (tracked_touches_start_ + 1) % kNumTrackedTouches;
-    }
-  }
-}
-
-void SinglePositionTouchNoiseFilter::TrackTouch(
-    const InProgressTouchEvdev& touch,
-    base::TimeDelta time) {
-  size_t index = (tracked_touches_end_ + 1) % kNumTrackedTouches;
-  // If we would reach the start touch index, we cannot track any more touches.
-  if (index == tracked_touches_start_)
-    return;
-
-  tracked_touches_end_ = index;
-  tracked_touches_[index].valid = true;
-  tracked_touches_[index].slot = touch.slot;
-  tracked_touches_[index].x = touch.x;
-  tracked_touches_[index].y = touch.y;
-  tracked_touches_[index].begin = time;
-  tracked_touches_[index].end = time;
-  tracked_slots_[touch.slot] = index;
-}
-
-SinglePositionTouchNoiseFilter::SinglePositionTouchNoiseFilter::TrackedTouch::
-    TrackedTouch()
-    : valid(false), slot(0), x(0), y(0) {
-}
-
-SinglePositionTouchNoiseFilter::SinglePositionTouchNoiseFilter::TrackedTouch::
-    ~TrackedTouch() {
-}
-
-}  // namespace ui