1// Copyright (C) 2016 The Qt Company Ltd.
2// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
3
4#include "genericalssensor.h"
5#include <QDebug>
6
7char const * const genericalssensor::id("generic.als");
8
9genericalssensor::genericalssensor(QSensor *sensor)
10 : QSensorBackend(sensor)
11{
12 lightSensor = new QLightSensor(this);
13 lightSensor->addFilter(filter: this);
14 lightSensor->connectToBackend();
15
16 setReading<QAmbientLightReading>(&m_reading);
17 setDataRates(lightSensor);
18}
19
20void genericalssensor::start()
21{
22 lightSensor->setDataRate(sensor()->dataRate());
23 lightSensor->setAlwaysOn(sensor()->isAlwaysOn());
24 lightSensor->start();
25 if (!lightSensor->isActive())
26 sensorStopped();
27 if (lightSensor->isBusy())
28 sensorBusy();
29}
30
31void genericalssensor::stop()
32{
33 lightSensor->stop();
34}
35
36struct lux_limit {
37 int min;
38 int max;
39};
40
41// Defines the min and max lux values that a given level has.
42// These are used to add histeresis to the sensor.
43// If the previous level is below a level, the lux must be at or above the minimum.
44// If the previous level is above a level, the lux muyt be at or below the maximum.
45static lux_limit limits[] = {
46 { .min: 0, .max: 0 }, // Undefined (not used)
47 { .min: 0, .max: 5 }, // Dark
48 { .min: 10, .max: 50 }, // Twilight
49 { .min: 100, .max: 200 }, // Light
50 { .min: 500, .max: 2000 }, // Bright
51 { .min: 5000, .max: 0 } // Sunny
52};
53
54#if 0
55// Used for debugging
56static QString light_level(int level)
57{
58 switch (level) {
59 case 1:
60 return QLatin1String("Dark");
61 case 2:
62 return QLatin1String("Twilight");
63 case 3:
64 return QLatin1String("Light");
65 case 4:
66 return QLatin1String("Bright");
67 case 5:
68 return QLatin1String("Sunny");
69 default:
70 return QLatin1String("Undefined");
71 }
72}
73#endif
74
75bool genericalssensor::filter(QLightReading *reading)
76{
77 // It's unweildly dealing with these constants so make some
78 // local aliases that are shorter. This makes the code below
79 // much easier to read.
80 enum {
81 Undefined = QAmbientLightReading::Undefined,
82 Dark = QAmbientLightReading::Dark,
83 Twilight = QAmbientLightReading::Twilight,
84 Light = QAmbientLightReading::Light,
85 Bright = QAmbientLightReading::Bright,
86 Sunny = QAmbientLightReading::Sunny
87 };
88
89 int lightLevel = m_reading.lightLevel();
90 qreal lux = reading->lux();
91
92 // Check for change direction to allow for histeresis
93 if (lightLevel < Sunny && lux >= limits[Sunny ].min) lightLevel = Sunny;
94 else if (lightLevel < Bright && lux >= limits[Bright ].min) lightLevel = Bright;
95 else if (lightLevel < Light && lux >= limits[Light ].min) lightLevel = Light;
96 else if (lightLevel < Twilight && lux >= limits[Twilight].min) lightLevel = Twilight;
97 else if (lightLevel < Dark && lux >= limits[Dark ].min) lightLevel = Dark;
98 else if (lightLevel > Dark && lux <= limits[Dark ].max) lightLevel = Dark;
99 else if (lightLevel > Twilight && lux <= limits[Twilight].max) lightLevel = Twilight;
100 else if (lightLevel > Light && lux <= limits[Light ].max) lightLevel = Light;
101 else if (lightLevel > Bright && lux <= limits[Bright ].max) lightLevel = Bright;
102
103 //qDebug() << "lightLevel" << light_level(lightLevel) << "lux" << lux;
104
105 if (static_cast<int>(m_reading.lightLevel()) != lightLevel || m_reading.timestamp() == 0) {
106 m_reading.setTimestamp(reading->timestamp());
107 m_reading.setLightLevel(static_cast<QAmbientLightReading::LightLevel>(lightLevel));
108
109 newReadingAvailable();
110 }
111
112 return false;
113}
114
115

source code of qtsensors/src/plugins/sensors/generic/genericalssensor.cpp