Create a new sensor type for distance.

Create a new sensor type for distance. This sensor type supports new hardware sensors
that can measure physical distance from the device, in centimeters. The API is designed
to mimic the Android API for proximity (TYPE_PROXIMITY), so that if a given proximity
sensor only supports a binary measurement (near vs far), then instead of reporting distance
in cm, the QDistanceSensor will return the max range value to represent far, and a lesser
value to represent close. Using this definition should simplify implementation.

The main reason for not implementing this as a new property of QProximitySensor is that
clients of QProximitySensor have made the assumption that they will receive the readingReady
signal if and only if the reading has changed from near to far or vice versa. Adding a
distance property will break that assumption, as distance has a higher degree of precision.

Change-Id: Ia804948c78ff7391fc8b78df975cddcf861326dc
Reviewed-by: Fabian Bumberger <fbumberger@rim.com>
Reviewed-by: Bernd Weimer <bweimer@blackberry.com>
Reviewed-by: Lorn Potter <lorn.potter@jollamobile.com>

1 files changed, 164 insertions, 0 deletions

diff --git a/src/sensors/qdistancesensor.cpp b/src/sensors/qdistancesensor.cpp
new file mode 100644
index 00000000..3cec9ca9
--- /dev/null
+++ b/src/sensors/qdistancesensor.cpp
@@ -0,0 +1,164 @@
+ /****************************************************************************
+ **
+ ** Copyright (C) 2014 BlackBerry Limited. All rights reserved.
+ ** Contact: http://www.qt-project.org/legal
+ **
+ ** This file is part of the QtSensors module of the Qt Toolkit.
+ **
+ ** $QT_BEGIN_LICENSE:LGPL$
+ ** 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 Digia.  For licensing terms and
+ ** conditions see http://qt.digia.com/licensing.  For further information
+ ** use the contact form at http://qt.digia.com/contact-us.
+ **
+ ** GNU Lesser General Public License Usage
+ ** Alternatively, 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, Digia gives you certain additional
+ ** rights.  These rights are described in the Digia 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.
+ **
+ **
+ ** $QT_END_LICENSE$
+ **
+ ****************************************************************************/
+
+#include <qdistancesensor.h>
+#include "qdistancesensor_p.h"
+
+QT_BEGIN_NAMESPACE
+
+IMPLEMENT_READING(QDistanceReading)
+
+/*!
+    \class QDistanceReading
+    \ingroup sensors_reading
+    \inmodule QtSensors
+    \since 5.4
+
+    \brief The QDistanceReading class holds distance reading in cm from the proximity sensor.
+
+    The QDistanceReading class holds distance reading in cm from the proximity sensor.
+    Note: Some proximity sensor only support two values for distance, a near and far value.
+    In this case, the sensor should report its maximum range value to represent the far state,
+    and a lesser value to represent the near state.
+
+    \section2 QDistanceReading Units
+    The distance is measured in cm
+
+    The distance sensor is typically located in the front face of a device, and thus will
+    measure the distance of an object from the device's front face.
+*/
+
+/*!
+    \property QDistanceReading::distance
+    \brief distance of object from front face of device
+
+    \sa {QDistanceReading Units}
+*/
+
+qreal QDistanceReading::distance() const
+{
+    return d->distance;
+}
+
+/*!
+    Sets distance to \a distance.
+*/
+void QDistanceReading::setDistance(qreal distance)
+{
+    d->distance = distance;
+}
+
+// =====================================================================
+
+/*!
+    \class QDistanceFilter
+    \ingroup sensors_filter
+    \inmodule QtSensors
+    \since 5.4
+
+    \brief The QDistanceFilter class is a convenience wrapper around QSensorFilter.
+
+    The only difference is that the filter() method features a pointer to QDistanceReading
+    instead of QSensorReading.
+*/
+
+/*!
+    \fn QDistanceFilter::filter(QDistanceReading *reading)
+
+    Called when \a reading changes. Returns false to prevent the reading from propagating.
+
+    \sa QSensorFilter::filter()
+*/
+
+bool QDistanceFilter::filter(QSensorReading *reading)
+{
+    return filter(static_cast<QDistanceReading*>(reading));
+}
+
+char const * const QDistanceSensor::type("QDistanceSensor");
+
+/*!
+    \class QDistanceSensor
+    \ingroup sensors_type
+    \inmodule QtSensors
+    \since 5.4
+
+    \brief The QDistanceSensor class is a convenience wrapper around QSensor.
+
+    The only behavioral difference is that this class sets the type properly.
+
+    This class also features a reading() function that returns a QDistanceReading instead of a QSensorReading.
+
+    For details about how the sensor works, see \l QDistanceReading.
+
+    \sa QDistanceReading
+*/
+
+/*!
+    Construct the sensor as a child of \a parent.
+*/
+QDistanceSensor::QDistanceSensor(QObject *parent)
+    : QSensor(QDistanceSensor::type, parent)
+{
+}
+
+/*!
+    Destroy the sensor. Stops the sensor if it has not already been stopped.
+*/
+QDistanceSensor::~QDistanceSensor()
+{
+}
+
+/*!
+    \fn QDistanceSensor::reading() const
+
+    Returns the reading class for this sensor.
+
+    \sa QSensor::reading()
+*/
+
+QDistanceReading *QDistanceSensor::reading() const
+{
+    return static_cast<QDistanceReading*>(QSensor::reading());
+}
+
+#include "moc_qdistancesensor.cpp"
+QT_END_NAMESPACE