/**************************************************************************** ** ** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies). ** All rights reserved. ** Contact: Nokia Corporation (qt-info@nokia.com) ** ** This file is part of the QtSensors module of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:LGPL$ ** GNU Lesser General Public License Usage ** This file may be used under the terms of the GNU Lesser General Public ** License version 2.1 as published by the Free Software Foundation and ** appearing in the file LICENSE.LGPL included in the packaging of this ** file. Please review the following information to ensure the GNU Lesser ** General Public License version 2.1 requirements will be met: ** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. ** ** In addition, as a special exception, Nokia gives you certain additional ** rights. These rights are described in the Nokia Qt LGPL Exception ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. ** ** GNU General Public License Usage ** Alternatively, this file may be used under the terms of the GNU General ** Public License version 3.0 as published by the Free Software Foundation ** and appearing in the file LICENSE.GPL included in the packaging of this ** file. Please review the following information to ensure the GNU General ** Public License version 3.0 requirements will be met: ** http://www.gnu.org/copyleft/gpl.html. ** ** Other Usage ** Alternatively, this file may be used in accordance with the terms and ** conditions contained in a signed written agreement between you and Nokia. ** ** ** ** ** ** $QT_END_LICENSE$ ** ****************************************************************************/ #include "qsensor.h" #include "qsensor_p.h" #include "qsensorbackend.h" #include "qsensormanager.h" #include #include #include QT_BEGIN_NAMESPACE /*! \typedef qrange \relates QSensor This type is defined as a QPair. \code typedef QPair qrange; \endcode \sa QPair, qrangelist, QSensor::availableDataRates */ /*! \typedef qrangelist \relates QSensor This type is defined as a list of qrange values. \code typedef QList qrangelist; \endcode \sa QList, qrange, QSensor::availableDataRates */ /*! \class qoutputrange \relates QSensor \brief The qoutputrange class holds the specifics of an output range. The class is defined as a simple struct. \code struct qoutputrange { qreal maximum; qreal minimum; qreal accuracy; }; \endcode Each output range specifies a minimum and maximum value as well as an accuracy value. The accuracy value represents the resolution of the sensor. It is the smallest change the sensor can detect and is expressed using the same units as the minimum and maximum. Sensors must often trade off range for accuracy. To allow the user to determine which of these are more important the sensor may offer several output ranges. One output range may have reduced minimum and maximum values and increased sensitivity. Another output range may have higher minimum and maximum values with reduced sensitivity. Note that higher sensitivities will be represented by smaller accuracy values. An example of this tradeoff can be seen by examining the LIS302DL accelerometer. It has only 256 possible values to report with. These values are scaled so that they can represent either -2G to +2G (with an accuracy value of 0.015G) or -8G to +8G (with an accuracy value of 0.06G). \sa qoutputrangelist, QSensor::outputRanges */ /*! \variable qoutputrange::maximum This is the maximum value for this output range. The units are defined by the sensor. */ /*! \variable qoutputrange::minimum This is the minimum value for this output range. The units are defined by the sensor. */ /*! \variable qoutputrange::accuracy The accuracy value represents the resolution of the sensor. It is the smallest change the sensor can detect and is expressed using the same units as the minimum and maximum. */ /*! \typedef qoutputrangelist \relates QSensor This type is defined as a list of qoutputrange values. \code typedef QList qoutputrangelist; \endcode \sa QList, qoutputrange, QSensor::outputRanges */ // A bit of a hack to call qRegisterMetaType when the library is loaded. static int qrange_id = qRegisterMetaType("qrange"); static int qrangelist_id = qRegisterMetaType("qrangelist"); static int qoutputrangelist_id = qRegisterMetaType("qoutputrangelist"); // ===================================================================== /*! \class QSensor \ingroup sensors_main \inmodule QtSensors \brief The QSensor class represents a single hardware sensor. The life cycle of a sensor is typically: \list \o Create a sub-class of QSensor on the stack or heap. \o Setup as required by the application. \o Start receiving values. \o Sensor data is used by the application. \o Stop receiving values. \endlist The sensor data is delivered via QSensorReading and its sub-classes. \sa QSensorReading */ /*! Construct the \a type sensor as a child of \a parent. */ QSensor::QSensor(const QByteArray &type, QObject *parent) : QObject(parent) , d(new QSensorPrivate) { d->type = type; registerInstance(); // so the availableSensorsChanged() signal works } /*! Destroy the sensor. Stops the sensor if it has not already been stopped. */ QSensor::~QSensor() { stop(); Q_FOREACH (QSensorFilter *filter, d->filters) filter->setSensor(0); delete d->backend; d->backend = 0; // owned by the backend d->device_reading = 0; d->filter_reading = 0; d->cache_reading = 0; } /*! \property QSensor::connectedToBackend \brief a value indicating if the sensor has connected to a backend. A sensor that has not been connected to a backend cannot do anything useful. Call the connectToBackend() method to force the sensor to connect to a backend immediately. This is automatically called if you call start() so you only need to do this if you need access to sensor properties (ie. to poll the sensor's meta-data before you use it). */ bool QSensor::isConnectedToBackend() const { return (d->backend != 0); } /*! \property QSensor::sensorid \brief the backend identifier for the sensor. Note that the identifier is filled out automatically when the sensor is connected to a backend. If you want to connect a specific backend, you should call setIdentifier() before connectToBackend(). */ QByteArray QSensor::identifier() const { return d->identifier; } void QSensor::setIdentifier(const QByteArray &identifier) { if (isConnectedToBackend()) { qWarning() << "ERROR: Cannot call QSensor::setIdentifier while connected to a backend!"; return; } d->identifier = identifier; } /*! \property QSensor::type \brief the type of the sensor. */ QByteArray QSensor::type() const { return d->type; } /*! Try to connect to a sensor backend. Returns true if a suitable backend could be found, false otherwise. The type must be set before calling this method if you are using QSensor directly. \sa isConnectedToBackend() */ bool QSensor::connectToBackend() { if (isConnectedToBackend()) return true; d->backend = QSensorManager::createBackend(this); // Reset the properties to their default values and re-set them now so // that the logic we've put into the setters gets called. if (d->dataRate != 0) { int tmp = d->dataRate; d->dataRate = 0; setDataRate(tmp); } if (d->outputRange != -1) { int tmp = d->outputRange; d->outputRange = -1; setOutputRange(tmp); } return isConnectedToBackend(); } /*! \property QSensor::busy \brief a value to indicate if the sensor is busy. Some sensors may be on the system but unavailable for use. This function will return true if the sensor is busy. You will not be able to start() the sensor. Note that this function does not return true if you are using the sensor, only if another process is using the sensor. \sa busyChanged() */ bool QSensor::isBusy() const { return d->busy; } /*! \fn QSensor::busyChanged() This signal is emitted when the sensor is no longer busy. This can be used to grab a sensor when it becomes available. \code sensor.start(); if (sensor.isBusy()) { // need to wait for busyChanged signal and try again } \endcode */ /*! \property QSensor::active \brief a value to indicate if the sensor is active. This is true if the sensor is active (returning values). This is false otherwise. Note that setting this value to true will not have an immediate effect. Instead, the sensor will be started once the event loop has been reached. */ void QSensor::setActive(bool active) { if (active == isActive()) return; if (active) QTimer::singleShot(0, this, SLOT(start())); // delay ensures all properties have been set if using QML else stop(); } bool QSensor::isActive() const { return d->active; } /*! \property QSensor::alwaysOn \brief a value to indicate if the sensor should remain running when the screen is off. Some platforms have a policy of suspending sensors when the screen turns off. Setting this property to true will ensure the sensor continues to run. */ void QSensor::setAlwaysOn(bool alwaysOn) { d->alwaysOn = alwaysOn; } bool QSensor::isAlwaysOn() const { return d->alwaysOn; } /*! \property QSensor::availableDataRates \brief the data rates that the sensor supports. This is a list of the data rates that the sensor supports. Measured in Hertz. Entries in the list can represent discrete rates or a continuous range of rates. A discrete rate is noted by having both values the same. See the sensor_explorer example for an example of how to interpret and use this information. Note that this information is not mandatory as not all sensors have a rate at which they run. In such cases, the list will be empty. \sa QSensor::dataRate, qrangelist */ qrangelist QSensor::availableDataRates() const { return d->availableDataRates; } /*! \property QSensor::dataRate \brief the data rate that the sensor should be run at. Measured in Hertz. The data rate is the maximum frequency at which the sensor can detect changes. Setting this property is not portable and can cause conflicts with other applications. Check with the sensor backend and platform documentation for any policy regarding multiple applications requesting a data rate. The default value (0) means that the app does not care what the data rate is. Applications should consider using a timer-based poll of the current value or ensure that the code that processes values can run very quickly as the platform may provide updates hundreds of times each second. This should be set before calling start() because the sensor may not notice changes to this value while it is running. Note that there is no mechanism to determine the current data rate in use by the platform. \sa QSensor::availableDataRates */ int QSensor::dataRate() const { return d->dataRate; } void QSensor::setDataRate(int rate) { if (rate == 0 || !isConnectedToBackend()) { d->dataRate = rate; return; } bool warn = true; Q_FOREACH (const qrange &range, d->availableDataRates) { if (rate >= range.first && rate <= range.second) { warn = false; d->dataRate = rate; break; } } if (warn) { qWarning() << "setDataRate:" << rate << "is not supported by the sensor."; } } /*! Start retrieving values from the sensor. Returns true if the sensor was started, false otherwise. The sensor may fail to start for several reasons. Once an application has started a sensor it must wait until the sensor receives a new value before it can query the sensor's values. This is due to how the sensor receives values from the system. Sensors do not (in general) poll for new values, rather new values are pushed to the sensors as they happen. For example, this code will not work as intended. \badcode sensor->start(); sensor->reading()->x(); // no data available \endcode To work correctly, the code that accesses the reading should ensure the readingChanged() signal has been emitted. \code connect(sensor, SIGNAL(readingChanged()), this, SLOT(checkReading())); sensor->start(); } void MyClass::checkReading() { sensor->reading()->x(); \endcode \sa QSensor::busy */ bool QSensor::start() { if (isActive()) return true; if (!connectToBackend()) return false; // Set these flags to their defaults d->active = true; d->busy = false; // Backend will update the flags appropriately d->backend->start(); Q_EMIT activeChanged(); return isActive(); } /*! Stop retrieving values from the sensor. This releases the sensor so that other processes can use it. \sa QSensor::busy */ void QSensor::stop() { if (!isConnectedToBackend() || !isActive()) return; d->active = false; d->backend->stop(); Q_EMIT activeChanged(); } /*! \property QSensor::reading \brief the reading class. The reading class provides access to sensor readings. The reading object is a volatile cache of the most recent sensor reading that has been received so the application should process readings immediately or save the values somewhere for later processing. Note that this will return 0 until a sensor backend is connected to a backend. Also note that readings are not immediately available after start() is called. Applications must wait for the readingChanged() signal to be emitted. \sa isConnectedToBackend(), start() */ QSensorReading *QSensor::reading() const { return d->cache_reading; } /*! Add a \a filter to the sensor. The sensor does not take ownership of the filter. QSensorFilter will inform the sensor if it is destroyed. \sa QSensorFilter */ void QSensor::addFilter(QSensorFilter *filter) { if (!filter) { qWarning() << "addFilter: passed a null filter!"; return; } filter->setSensor(this); d->filters << filter; } /*! Remove \a filter from the sensor. \sa QSensorFilter */ void QSensor::removeFilter(QSensorFilter *filter) { if (!filter) { qWarning() << "removeFilter: passed a null filter!"; return; } d->filters.removeOne(filter); filter->setSensor(0); } /*! Returns the filters currently attached to the sensor. \sa QSensorFilter */ QList QSensor::filters() const { return d->filters; } /*! \fn QSensor::d_func() const \internal */ /*! \fn QSensor::readingChanged() This signal is emitted when a new sensor reading is received. The sensor reading can be found in the QSensor::reading property. Note that the reading object is a volatile cache of the most recent sensor reading that has been received so the application should process the reading immediately or save the values somewhere for later processing. Before this signal has been emitted for the first time, the reading object will have uninitialized data. \sa start() */ /*! \fn QSensor::activeChanged() This signal is emitted when the QSensor::active property has changed. \sa QSensor::active */ /*! \property QSensor::outputRanges \brief a list of output ranges the sensor supports. A sensor may have more than one output range. Typically this is done to give a greater measurement range at the cost of lowering accuracy. Note that this information is not mandatory. This information is typically only available for sensors that have selectable output ranges (such as typical accelerometers). \sa QSensor::outputRange, qoutputrangelist */ qoutputrangelist QSensor::outputRanges() const { return d->outputRanges; } /*! \property QSensor::outputRange \brief the output range in use by the sensor. This value represents the index in the QSensor::outputRanges list to use. Setting this property is not portable and can cause conflicts with other applications. Check with the sensor backend and platform documentation for any policy regarding multiple applications requesting an output range. The default value (-1) means that the app does not care what the output range is. Note that there is no mechanism to determine the current output range in use by the platform. \sa QSensor::outputRanges */ int QSensor::outputRange() const { return d->outputRange; } void QSensor::setOutputRange(int index) { if (index == -1 || !isConnectedToBackend()) { d->outputRange = index; return; } bool warn = true; if (index >= 0 && index < d->outputRanges.count()) { warn = false; d->outputRange = index; } if (warn) { qWarning() << "setOutputRange:" << index << "is not supported by the sensor."; } } /*! \property QSensor::description \brief a descriptive string for the sensor. */ QString QSensor::description() const { return d->description; } /*! \property QSensor::error \brief the last error code set on the sensor. Note that error codes are sensor-specific. */ int QSensor::error() const { return d->error; } /*! \fn QSensor::sensorError(int error) This signal is emitted when an \a error code is set on the sensor. Note that some errors will cause the sensor to stop working. You should call isActive() to determine if the sensor is still running. */ /*! \fn QSensor::availableSensorsChanged() This signal is emitted when the list of available sensors has changed. The sensors available to a program will not generally change over time however some of the avilable sensors may represent hardware that is not permanently connected. For example, a game controller that is connected via bluetooth would become available when it was on and would become unavailable when it was off. \sa QSensor::sensorTypes(), QSensor::sensorsForType() */ /*! \property QSensor::maxBufferSize The property holds the maximum buffer size. Note that this may be undefined, in which case the sensor does not support any form of buffering. \sa QSensor::bufferSize, QSensor::efficientBufferSize */ /*! \property QSensor::efficientBufferSize The property holds the most efficient buffer size. Normally this is 1 (which means no particular size is most efficient). Some sensor drivers have a FIFO buffer which makes it more efficient to deliver the FIFO's size worth of readings at one time. Note that this may be undefined, in which case the sensor does not support any form of buffering. \sa QSensor::bufferSize, QSensor::maxBufferSize */ /*! \property QSensor::bufferSize This property holds the size of the buffer. By default (and if the property is left undefined), the buffer size is 1, which means no buffering. If the maximum buffer size is 1 (or undefined), then buffering is not supported by the sensor. Setting bufferSize greater than maxBufferSize will cause maxBufferSize to be used. Buffering is turned on when bufferSize is greater than 1. The sensor will collect the requested number of samples and deliver them all to the application at one time. They will be delivered to the application as a burst of changed readings so it is particularly important that the application processes each reading immediately or saves the values somewhere else. If stop() is called when buffering is on-going, the partial buffer is not delivered. When the sensor is started with buffering option, values are collected from that moment onwards. There is no pre-existing buffer that can be utilized. The buffer size can only be changed while the sensor is not active. \sa QSensor::maxBufferSize, QSensor::efficientBufferSize */ // ===================================================================== /*! \class QSensorFilter \ingroup sensors_main \inmodule QtSensors \brief The QSensorFilter class provides an efficient callback facility for asynchronous notifications of sensor changes. Some sensors (eg. the accelerometer) are often accessed very frequently. This may be slowed down by the use of signals and slots. The QSensorFilter interface provides a more efficient way for the sensor to notify your class that the sensor has changed. Additionally, multiple filters can be added to a sensor. They are called in order and each filter has the option to modify the values in the reading or to suppress the reading altogether. Note that the values in the class returned by QSensor::reading() will not be updated until after the filters have been run. \sa filter() */ /*! \internal */ QSensorFilter::QSensorFilter() : m_sensor(0) { } /*! Notifies the attached sensor (if any) that the filter is being destroyed. */ QSensorFilter::~QSensorFilter() { if (m_sensor) m_sensor->removeFilter(this); } /*! \fn QSensorFilter::filter(QSensorReading *reading) This function is called when the sensor \a reading changes. The filter can modify the reading. Returns true to allow the next filter to receive the value. If this is the last filter, returning true causes the signal to be emitted and the value is stored in the sensor. Returns false to drop the reading. */ /*! \internal */ void QSensorFilter::setSensor(QSensor *sensor) { m_sensor = sensor; } // ===================================================================== /*! \class QSensorReading \ingroup sensors_main \inmodule QtSensors \brief The QSensorReading class holds the readings from the sensor. Note that QSensorReading is not particularly useful by itself. The interesting data for each sensor is defined in a sub-class of QSensorReading. */ /*! \internal */ QSensorReading::QSensorReading(QObject *parent, QSensorReadingPrivate *_d) : QObject(parent) , d(_d?_d:new QSensorReadingPrivate) { } /*! \internal */ QSensorReading::~QSensorReading() { } /*! \property QSensorReading::timestamp \brief the timestamp of the reading. Timestamps values are microseconds since a fixed point. You can use timestamps to see how far apart two sensor readings are. Note that sensor timestamps from different sensors may not be directly comparable (as they may choose different fixed points for their reference). \bold{Note that some platforms do not deliver timestamps correctly}. Applications should be prepared for occasional issues that cause timestamps to jump backwards. */ /*! Returns the timestamp of the reading. */ quint64 QSensorReading::timestamp() const { return d->timestamp; } /*! Sets the \a timestamp of the reading. */ void QSensorReading::setTimestamp(quint64 timestamp) { d->timestamp = timestamp; } /*! Returns the number of extra properties that the reading has. Note that this does not count properties declared in QSensorReading. As an example, this returns 3 for QAccelerometerReading because there are 3 properties defined in that class. */ int QSensorReading::valueCount() const { const QMetaObject *mo = metaObject(); return mo->propertyCount() - mo->propertyOffset(); } /*! Returns the value of the property at \a index. Note that this function is slower than calling the data function directly. Here is an example of getting a property via the different mechanisms available. Accessing directly provides the best performance but requires compile-time knowledge of the data you are accessing. \code QAccelerometerReading *reading = ...; qreal x = reading->x(); \endcode You can also access a property by name. To do this you must call QObject::property(). \code qreal x = reading->property("x").value(); \endcode Finally, you can access values via numeric index. \code qreal x = reading->value(0).value(); \endcode Note that value() can only access properties declared with Q_PROPERTY() in sub-classes of QSensorReading. \sa valueCount(), QObject::property() */ QVariant QSensorReading::value(int index) const { // get them meta-object const QMetaObject *mo = metaObject(); // determine the index of the property we want index += mo->propertyOffset(); // get the meta-property QMetaProperty property = mo->property(index); // read the property return property.read(this); } /*! \fn QSensorReading::copyValuesFrom(QSensorReading *other) \internal Copy values from other into this reading. Implemented by sub-classes using the DECLARE_READING() and IMPLEMENT_READING() macros. Note that this method should only be called by QSensorBackend. */ void QSensorReading::copyValuesFrom(QSensorReading *other) { QSensorReadingPrivate *my_ptr = d.data(); QSensorReadingPrivate *other_ptr = other->d.data(); /* Do a direct copy of the private class */ *(my_ptr) = *(other_ptr); } /*! \fn QSensorReading::d_ptr() \internal No longer used. Exists to keep the winscw build happy. */ /*! \macro DECLARE_READING(classname) \relates QSensorReading \brief The DECLARE_READING macro adds some required methods to a reading class. This macro should be used for all reading classes. Pass the \a classname of your reading class. \code class MyReading : public QSensorReading { Q_OBJECT Q_PROPERTY(qreal myprop READ myprop) DECLARE_READING(MyReading) public: qreal myprop() const; vod setMyprop(qreal myprop); }; \endcode \sa IMPLEMENT_READING() */ /*! \macro IMPLEMENT_READING(classname) \relates QSensorReading \brief The IMPLEMENT_READING macro implements the required methods for a reading class. This macro should be used for all reading classes. It should be placed into a single compilation unit (source file), not into a header file. Pass the \a classname of your reading class. \code IMPLEMENT_READING(MyReading) \endcode \sa DECLARE_READING() */ #include "moc_qsensor.cpp" QT_END_NAMESPACE