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/*!
    \example grue
    \title Qt Sensors - Grue Sensor Example
    \brief The Qt Sensors - Grue sensor example demonstrates all the steps from creating a new sensor to using it.
    \ingroup qtsensors-examples

    \image qtsensors-examples-grue.png

    The Qt Sensors - Grue sensor example demonstrates all the steps from creating a new sensor to using it.

    The sensor definition is placed in a library where client apps can access it. The actual implementation
    lives in a plugin.

    \list
    \li \l{Grue Sensor Definition}
    \li \l{Grue Sensor Implementation}
    \endlist

    The sensor can now be used by a C++ application, even if the application does not have access to the
    definition.

    \list
    \li \l{Grue Sensor Console Application}
    \endlist

    To make the sensor available to a QML application an import must be created.

    \list
    \li \l{Grue Sensor QML Import}
    \li \l{Grue Sensor QML Application}
    \endlist

    \section1 Grue Sensor Definition

    The Grue sensor is defined in a library so that applications can use it.
    The source code is available in the \c{grue/lib} subdirectory.

    First up is the sensor type. This is the interface for sensors that report
    on your likelihood of being eaten by a Grue. Such sensors are very important
    to adventurers, particularly if they are going into dark places as this is
    where Grues live.

    The interface is a simple one. It provides only 1 piece of information, your
    chance of being eaten. For the details on how this is property should be
    interpreted please see the documentation in gruesensor.cpp.

    This example was created using the make_sensor.pl script which can be found in
    src/sensors. As such, it contains some generated code that defines the convenience
    classes GrueFilter and GrueSensor.

    \section1 Grue Sensor Implementation

    The Grue sensor implementation lives in a plugin that is loaded by the Qt Sensors
    library. The source code is available in the \c{grue/plugin} subdirectory.

    The Grue sensor needs a backend before it can be used. The backend provided
    is rather basic and it relies on some kind of light sensor to work but it
    gets the job done. If new hardware that can detect the actual presence of Grues
    becomes available a backend could be created that supports this hardware and
    applications using the Grue sensor would be able to use it without any changes.

    There are a few mandatory parts to a backend. They are the start and stop methods
    and the setReading call. The start and stop methods are used to start and stop
    any underlying hardware. In the case of this backend they start and stop a
    light sensor. In the start method, the backend should be sure to call the
    sensorStopped() or sensorBusy() methods if it cannot start.

    \snippet grue/plugin/gruesensorimpl.cpp start

    The setReading method is needed so that the sensors library knows where the
    readings are coming from. This backend has a local copy of the reading so
    it passes a pointer to the function.

    \snippet grue/plugin/gruesensorimpl.cpp setReading

    However it is also possible to pass null to the setReading method in which
    case the sensors library will create an instance and return a pointer.

    \code
    // Create a reading instance for us to use
    m_reading = setReading<GrueSensorReading>(0);
    \endcode

    The Grue sensor backend also supplies some metadata.

    The backend checks 2 things, how dark it is and how long you have been in the dark.
    It uses the readingChanged() signal to know when to check the light sensor's
    value. Once it is dark, it uses a timer to increase your chance of being eaten.

    The Grue sensor backend is delivered as a plugin. The plugin has a factory object
    that registers the types available and does the actual instantiation of the backend.

    \section1 Grue Sensor Console Application

    The Grue sensor console application demonstrates use of the Grue sensor.
    The source code is available in the \c{grue/console_app} subdirectory.

    This is a simple commandline application. It demonstrates how to use the generic
    access feature of Qt Sensors to avoid a link-time dependency on the Grue Sensor
    library.

    \section1 Grue Sensor QML Import

    The Grue sensor QML import exports the GrueSensor class as a QML type.
    The source code is available in the \c{grue/import} subdirectory.

    This creates the \e {Grue 1.0} import.

    \section1 Grue Sensor QML Application

    The Grue sensor QML application demonstrates the use of GrueSensor QML type.

    The application consists of a single QML file and an image. It is built as an
    exucutable with C++ code that runs the QML, but it can also be launched directly
    using the \c qmlscene tool.

    You should build the top-level 'grue' project before trying to run
    this example or it will not be able to find its dependencies.

    \code
    qmlscene -I . grue.qml
    \endcode

    Above, the \c{-I .} parameter adds the current directory as a module import
    path to locate the Grue QML module.
*/
