Add documentation for the HeartRate game example

Change-Id: I0f0a82be359fc49becd1eccc67697d5177d73bb1
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@qt.io>
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>

examples/bluetooth/heartrate-game/doc/src/heartrate-game.qdoc

+/****************************************************************************
+**
+** Copyright (C) 2017 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the documentation of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:FDL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Free Documentation License Usage
+** Alternatively, this file may be used under the terms of the GNU Free
+** Documentation License version 1.3 as published by the Free Software
+** Foundation and appearing in the file included in the packaging of
+** this file. Please review the following information to ensure
+** the GNU Free Documentation License version 1.3 requirements
+** will be met: http://www.gnu.org/copyleft/fdl.html.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+/*!
+    \example heartrate-game
+    \title Bluetooth Low Energy Heart Rate Game
+    \brief A game demonstrating the interaction with a Bluetooth Low Energy Heart Rate
+    device/service.
+
+    The Bluetooth Low Energy Heart Rate Game shows how to develop a Bluetooth Low Energy
+    application using the Qt Bluetooth API. The application covers the scanning for
+    Bluetooth Low Energy devices, connecting to a Heart Rate service on the device, writing
+    characteristics and descriptors, and receiving updates from the device once the heart rate
+    has changed.
+
+    \image heartgame-start.png
+
+    The example introduces the following Qt classes:
+
+    \list
+        \li \l QLowEnergyController
+        \li \l QLowEnergyService
+        \li \l QLowEnergyCharacteristic
+        \li \l QLowEnergyDescriptor
+    \endlist
+
+    A Bluetooth Low Energy device with a Heart Rate
+    service is required for this application to work. An alternative might be a programmable
+    Bluetooth Low Energy device which might simulate the service. You can also use the
+    \l {heartrate-server} {Heart Rate server} example for that purpose.
+    If no such device can be found, the example uses a demo mode which creates and displays
+    random values.
+
+    The goal of the game is to increase the measured heart rate as much as possible.
+
+    The \l {lowenergyscanner}{Bluetooth Low Energy Scanner} example might be more suitable
+    if a heart rate device is not available. The scanner example works with any type of Bluetooth
+    Low Energy peripheral device.
+
+    \include examples-run.qdocinc
+
+    \section1 Visual Tour
+
+    The application searches for all Bluetooth Low Energy peripheral devices in the vicinity.
+    It is assumed that the remote devices advertise their presence. The found devices are
+    presented in a list. Note that all found Bluetooth Low Energy devices are listed even
+    if they do not offer a Heart Rate service.
+
+    \image heartgame-search.png
+
+    After the user has selected a target device, the example connects to its Heart Rate service
+    if one is available. It automatically enables notification updates for the Heart Rate value
+    and presents the current value on the screen.
+
+    \image heartgame-running.png
+
+    Once the monitoring process is canceled, a small graph presents a summary of the received
+    values.
+
+    \image heartgame-result.png
+
+*/

src/bluetooth/doc/src/bluetooth-index.qdoc

@@ -181,6 +181,7 @@ A quick way to enable all QtBluetooth logging is to add the following line to th
         \li \l {pingpong}{QML Bluetooth PingPong}
         \li \l {chat}{QML Bluetooth Chat}
         \li \l {heartlistener}{Bluetooth Low Energy Heart Listener}
+        \li \l {heartrate-game}{Bluetooth Low Energy Heart Rate Game}
         \li \l {heartrate-server}{Bluetooth Low Energy Heart Rate Server}
         \li \l {lowenergyscanner}{Bluetooth Low Energy Scanner}
     \endlist