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>

3 files changed, 222 insertions, 0 deletions

diff --git a/src/imports/sensors/qmldistancesensor.cpp b/src/imports/sensors/qmldistancesensor.cpp
new file mode 100644
index 00000000..549c9e1e
--- /dev/null
+++ b/src/imports/sensors/qmldistancesensor.cpp
@@ -0,0 +1,133 @@
+/****************************************************************************
+**
+** 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 "qmldistancesensor.h"
+#include <QDistanceSensor>
+
+/*!
+    \qmltype DistanceSensor
+    \instantiates QmlDistanceSensor
+    \ingroup qml-sensors_type
+    \inqmlmodule QtSensors
+    \since QtSensors 5.4
+    \inherits Sensor
+    \brief The DistanceSensor element reports the distance in cm from an object to the device.
+
+    The DistanceSensor element reports the distance in cm from an object to the device.
+
+    This element wraps the QDistanceSensor class. Please see the documentation for
+    QDistanceSensor for details.
+
+    \sa DistanceReading
+*/
+
+QmlDistanceSensor::QmlDistanceSensor(QObject *parent)
+    : QmlSensor(parent)
+    , m_sensor(new QDistanceSensor(this))
+{
+}
+
+QmlDistanceSensor::~QmlDistanceSensor()
+{
+}
+
+QmlSensorReading *QmlDistanceSensor::createReading() const
+{
+    return new QmlDistanceReading(m_sensor);
+}
+
+QSensor *QmlDistanceSensor::sensor() const
+{
+    return m_sensor;
+}
+
+/*!
+    \qmltype DistanceReading
+    \instantiates QmlDistanceReading
+    \ingroup qml-sensors_reading
+    \inqmlmodule QtSensors
+    \since QtSensors 5.4
+    \inherits SensorReading
+    \brief The DistanceReading element holds the most recent DistanceSensor reading.
+
+    The DistanceReading element holds the most recent DistanceSensor reading.
+
+    This element wraps the QDistanceReading class. Please see the documentation for
+    QDistanceReading for details.
+
+    This element cannot be directly created.
+*/
+
+QmlDistanceReading::QmlDistanceReading(QDistanceSensor *sensor)
+    : QmlSensorReading(sensor)
+    , m_sensor(sensor)
+    , m_distance(0.0)
+{
+}
+
+QmlDistanceReading::~QmlDistanceReading()
+{
+}
+
+/*!
+    \qmlproperty qreal DistanceReading::distance
+    This property holds the distance measurement
+
+    Please see QDistanceReading::distance for information about this property.
+*/
+
+qreal QmlDistanceReading::distance() const
+{
+    return m_distance;
+}
+
+QSensorReading *QmlDistanceReading::reading() const
+{
+    return m_sensor->reading();
+}
+
+void QmlDistanceReading::readingUpdate()
+{
+    qreal distance = m_sensor->reading()->distance();
+    if (m_distance != distance) {
+        m_distance = distance;
+        Q_EMIT distanceChanged();
+    }
+}
diff --git a/src/imports/sensors/qmldistancesensor.h b/src/imports/sensors/qmldistancesensor.h
new file mode 100644
index 00000000..3f1f51a7
--- /dev/null
+++ b/src/imports/sensors/qmldistancesensor.h
@@ -0,0 +1,87 @@
+/****************************************************************************
+**
+** 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.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QMLDISTANCESENSOR_H
+#define QMLDISTANCESENSOR_H
+
+#include "qmlsensor.h"
+
+QT_BEGIN_NAMESPACE
+
+class QDistanceSensor;
+
+class QmlDistanceSensor : public QmlSensor
+{
+    Q_OBJECT
+public:
+    explicit QmlDistanceSensor(QObject *parent = 0);
+    ~QmlDistanceSensor();
+
+private:
+    QSensor *sensor() const Q_DECL_OVERRIDE;
+    QmlSensorReading *createReading() const Q_DECL_OVERRIDE;
+
+    QDistanceSensor *m_sensor;
+};
+
+class QmlDistanceReading : public QmlSensorReading
+{
+    Q_OBJECT
+    Q_PROPERTY(qreal distance READ distance NOTIFY distanceChanged)
+public:
+    explicit QmlDistanceReading(QDistanceSensor *sensor);
+    ~QmlDistanceReading();
+
+    qreal distance() const;
+
+Q_SIGNALS:
+    void distanceChanged();
+
+private:
+    QSensorReading *reading() const Q_DECL_OVERRIDE;
+    void readingUpdate() Q_DECL_OVERRIDE;
+
+    QDistanceSensor *m_sensor;
+    qreal m_distance;
+};
+
+QT_END_NAMESPACE
+#endif
diff --git a/src/imports/sensors/sensors.pro b/src/imports/sensors/sensors.pro
index 2236ce11..73e9c189 100644
--- a/src/imports/sensors/sensors.pro
+++ b/src/imports/sensors/sensors.pro
@@ -13,6 +13,7 @@ HEADERS += \
     qmlambientlightsensor.h \
     qmlambienttemperaturesensor.h \
     qmlcompass.h \
+    qmldistancesensor.h \
     qmlgyroscope.h \
     qmlholstersensor.h \
     qmlirproximitysensor.h \
@@ -35,6 +36,7 @@ SOURCES += sensors.cpp \
     qmlambientlightsensor.cpp \
     qmlambienttemperaturesensor.cpp \
     qmlcompass.cpp \
+    qmldistancesensor.cpp \
     qmlgyroscope.cpp \
     qmlholstersensor.cpp \
     qmlirproximitysensor.cpp \