chromium/ui/events/ozone/evdev/touch_filter/heuristic_stylus_palm_detection_filter.h

// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_EVENTS_OZONE_EVDEV_TOUCH_FILTER_HEURISTIC_STYLUS_PALM_DETECTION_FILTER_H_
#define UI_EVENTS_OZONE_EVDEV_TOUCH_FILTER_HEURISTIC_STYLUS_PALM_DETECTION_FILTER_H_

#include <bitset>
#include <vector>

#include "base/time/time.h"
#include "ui/events/ozone/evdev/event_device_info.h"
#include "ui/events/ozone/evdev/touch_evdev_types.h"
#include "ui/events/ozone/evdev/touch_filter/palm_detection_filter.h"
#include "ui/events/ozone/evdev/touch_filter/shared_palm_detection_filter_state.h"

namespace ui {

// A heuristic implementation of PalmDetectionFilter.
// Relies on firmware palm detection, but modifies behavior _after_ a stylus
// touch since our mutual-exclusion of stylus/touch means that we do not trust
// the device right after stylus.
// Configured with 3 inputs:
// 1. How many strokes to hold on to when holding.
// 2. TimeDelta for cancellation: any strokes started within this delta are
// cancelled automatically.
// 3. TimeDelta for hold: any strokes started after the cancellation and before
// this are held for the stroke count (as above). If they're cancelled
// externally, we never report them. If they terminate before the count, we
// output all items.
//
// NOTE: This filter is only intended for certain boards of hardware that have
// poor interaction between a mutually exclusive stylus and finger input:
// Turning it on for devices where is not intended will probably degrade
// performance and create a poor UX.
class COMPONENT_EXPORT(EVDEV) HeuristicStylusPalmDetectionFilter
    : public PalmDetectionFilter { … };

}  // namespace ui

#endif  // UI_EVENTS_OZONE_EVDEV_TOUCH_FILTER_HEURISTIC_STYLUS_PALM_DETECTION_FILTER_H_