services/inputflinger/reader/mapper/TouchCursorInputMapperCommon.cpp

/*
 * Copyright (C) 2022 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <input/DisplayViewport.h>
#include <stdint.h>
#include <ui/Rotation.h>

#include "EventHub.h"
#include "InputListener.h"
#include "InputReaderContext.h"

namespace android {

namespace {

[[nodiscard]] std::list<NotifyArgs> synthesizeButtonKey(
        InputReaderContext* context, int32_t action, nsecs_t when, nsecs_t readTime,
        int32_t deviceId, uint32_t source, int32_t displayId, uint32_t policyFlags,
        int32_t lastButtonState, int32_t currentButtonState, int32_t buttonState, int32_t keyCode) {
    std::list<NotifyArgs> out;
    if ((action == AKEY_EVENT_ACTION_DOWN && !(lastButtonState & buttonState) &&
         (currentButtonState & buttonState)) ||
        (action == AKEY_EVENT_ACTION_UP && (lastButtonState & buttonState) &&
         !(currentButtonState & buttonState))) {
        out.push_back(NotifyKeyArgs(context->getNextId(), when, readTime, deviceId, source,
                                    displayId, policyFlags, action, 0, keyCode, 0,
                                    context->getGlobalMetaState(), when));
    }
    return out;
}

} // namespace

ui::Rotation getInverseRotation(ui::Rotation orientation) {
    switch (orientation) {
        case ui::ROTATION_90:
            return ui::ROTATION_270;
        case ui::ROTATION_270:
            return ui::ROTATION_90;
        default:
            return orientation;
    }
}

void rotateDelta(ui::Rotation orientation, float* deltaX, float* deltaY) {
    float temp;
    switch (orientation) {
        case ui::ROTATION_90:
            temp = *deltaX;
            *deltaX = *deltaY;
            *deltaY = -temp;
            break;

        case ui::ROTATION_180:
            *deltaX = -*deltaX;
            *deltaY = -*deltaY;
            break;

        case ui::ROTATION_270:
            temp = *deltaX;
            *deltaX = -*deltaY;
            *deltaY = temp;
            break;

        default:
            break;
    }
}

bool isPointerDown(int32_t buttonState) {
    return buttonState &
            (AMOTION_EVENT_BUTTON_PRIMARY | AMOTION_EVENT_BUTTON_SECONDARY |
             AMOTION_EVENT_BUTTON_TERTIARY);
}

[[nodiscard]] std::list<NotifyArgs> synthesizeButtonKeys(
        InputReaderContext* context, int32_t action, nsecs_t when, nsecs_t readTime,
        int32_t deviceId, uint32_t source, int32_t displayId, uint32_t policyFlags,
        int32_t lastButtonState, int32_t currentButtonState) {
    std::list<NotifyArgs> out;
    out += synthesizeButtonKey(context, action, when, readTime, deviceId, source, displayId,
                               policyFlags, lastButtonState, currentButtonState,
                               AMOTION_EVENT_BUTTON_BACK, AKEYCODE_BACK);
    out += synthesizeButtonKey(context, action, when, readTime, deviceId, source, displayId,
                               policyFlags, lastButtonState, currentButtonState,
                               AMOTION_EVENT_BUTTON_FORWARD, AKEYCODE_FORWARD);
    return out;
}

std::tuple<nsecs_t /*eventTime*/, nsecs_t /*readTime*/> applyBluetoothTimestampSmoothening(
        const InputDeviceIdentifier& identifier, nsecs_t currentEventTime, nsecs_t readTime,
        nsecs_t lastEventTime) {
    if (identifier.bus != BUS_BLUETOOTH) {
        return {currentEventTime, readTime};
    }

    // Assume the fastest rate at which a Bluetooth touch device can report input events is one
    // every 4 milliseconds, or 250 Hz. Timestamps for successive events from a Bluetooth device
    // will be separated by at least this amount.
    constexpr static nsecs_t MIN_BLUETOOTH_TIMESTAMP_DELTA = ms2ns(4);
    // We define a maximum smoothing time delta so that we don't generate events too far into the
    // future.
    constexpr static nsecs_t MAX_BLUETOOTH_SMOOTHING_DELTA = ms2ns(32);
    const nsecs_t smoothenedEventTime =
            std::min(std::max(currentEventTime, lastEventTime + MIN_BLUETOOTH_TIMESTAMP_DELTA),
                     currentEventTime + MAX_BLUETOOTH_SMOOTHING_DELTA);
    // If we are modifying the event time, treat this event as a synthetically generated event for
    // latency tracking purposes and use the event time as the read time (zero read latency).
    const nsecs_t smoothenedReadTime =
            smoothenedEventTime != currentEventTime ? currentEventTime : readTime;
    return {smoothenedEventTime, smoothenedReadTime};
}

} // namespace android