New QCameraInfo class.

The class allows to get the list of available cameras on the system as
well as getting some static information about them such as their unique
ID, display name, physical position and sensor orientation.

This makes QCamera::availableDevices() and QCamera::deviceDescription()
obsolete.

This patch contains the API, documentation and auto-tests but not the
actual implementation by each backend (except for retrieving the default
camera device).

[ChangeLog][QtMultimedia] Added new QCameraInfo class
[ChangeLog][QtMultimedia] QCamera: availableDevices() and
deviceDescription() are deprecated, use QCameraInfo instead

Change-Id: I64fd65729ab26a789468979ed5444ee90bb82cd0
Reviewed-by: Christian Stromme <christian.stromme@digia.com>

1 files changed, 289 insertions, 0 deletions

diff --git a/src/multimedia/camera/qcamerainfo.cpp b/src/multimedia/camera/qcamerainfo.cpp
new file mode 100644
index 000000000..218219c7e
--- /dev/null
+++ b/src/multimedia/camera/qcamerainfo.cpp
@@ -0,0 +1,289 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part 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 "qcamerainfo.h"
+
+#include "qcamera_p.h"
+#include "qmediaserviceprovider_p.h"
+
+#include <qvideodeviceselectorcontrol.h>
+#include <qcamerainfocontrol.h>
+
+QT_BEGIN_NAMESPACE
+
+/*!
+    \class QCameraInfo
+    \brief The QCameraInfo class provides general information about camera devices.
+    \since 5.3
+    \inmodule QtMultimedia
+    \ingroup multimedia
+    \ingroup multimedia_camera
+
+    QCameraInfo lets you query for camera devices that are currently available on the system.
+
+    The static functions defaultCamera() and availableCameras() provide you a list of all
+    available cameras.
+
+    This example prints the name of all available cameras:
+
+    \snippet multimedia-snippets/camera.cpp Camera listing
+
+    A QCameraInfo can be used to construct a QCamera. The following example instantiates a QCamera
+    whose camera device is named 'mycamera':
+
+    \snippet multimedia-snippets/camera.cpp Camera selection
+
+    You can also use QCameraInfo to get general information about a camera device such as
+    description, physical position on the system, or camera sensor orientation.
+
+    \snippet multimedia-snippets/camera.cpp Camera info
+
+    \sa QCamera
+*/
+
+class QCameraInfoPrivate
+{
+public:
+    QCameraInfoPrivate() : isNull(true), position(QCamera::UnspecifiedPosition), orientation(0)
+    { }
+
+    bool isNull;
+    QString deviceName;
+    QString description;
+    QCamera::Position position;
+    int orientation;
+};
+
+/*!
+    Constructs a camera info object for \a camera.
+
+    You can use it to query information about the \a camera object passed as argument.
+
+    If the \a camera is invalid, for example when no camera device is available on the system,
+    the QCameraInfo object will be invalid and isNull() will return true.
+*/
+QCameraInfo::QCameraInfo(const QCamera &camera)
+    : d(new QCameraInfoPrivate)
+{
+    const QVideoDeviceSelectorControl *deviceControl = camera.d_func()->deviceControl;
+    if (deviceControl) {
+        const int selectedDevice = deviceControl->selectedDevice();
+        d->deviceName = deviceControl->deviceName(selectedDevice);
+        d->description = deviceControl->deviceDescription(selectedDevice);
+        d->isNull = false;
+    }
+
+    const QCameraInfoControl *infoControl = camera.d_func()->infoControl;
+    if (infoControl) {
+        d->position = infoControl->cameraPosition(d->deviceName);
+        d->orientation = infoControl->cameraOrientation(d->deviceName);
+        d->isNull = false;
+    }
+}
+
+/*!
+    Constructs a camera info object from a camera device \a name.
+
+    If no such device exists, the QCameraInfo object will be invalid and isNull() will return true.
+*/
+QCameraInfo::QCameraInfo(const QByteArray &name)
+    : d(new QCameraInfoPrivate)
+{
+    if (!name.isNull()) {
+        QMediaServiceProvider *provider = QMediaServiceProvider::defaultServiceProvider();
+        const QByteArray service(Q_MEDIASERVICE_CAMERA);
+        if (provider->devices(service).contains(name)) {
+            d->deviceName = QString::fromLatin1(name);
+            d->description = provider->deviceDescription(service, name);
+            d->position = provider->cameraPosition(name);
+            d->orientation = provider->cameraOrientation(name);
+            d->isNull = false;
+        }
+    }
+}
+
+/*!
+    Constructs a copy of \a other.
+*/
+QCameraInfo::QCameraInfo(const QCameraInfo &other)
+    : d(other.d)
+{
+}
+
+/*!
+    Destroys the QCameraInfo.
+*/
+QCameraInfo::~QCameraInfo()
+{
+}
+
+/*!
+    Returns true if this QCameraInfo is equal to \a other.
+*/
+bool QCameraInfo::operator==(const QCameraInfo &other) const
+{
+    if (d == other.d)
+        return true;
+
+    return (d->deviceName == other.d->deviceName
+            && d->description == other.d->description
+            && d->position == other.d->position
+            && d->orientation == other.d->orientation);
+}
+
+/*!
+    Returns true if this QCameraInfo is null or invalid.
+*/
+bool QCameraInfo::isNull() const
+{
+    return d->isNull;
+}
+
+/*!
+    Returns the device name of the camera
+
+    This is a unique ID to identify the camera and may not be human-readable.
+*/
+QString QCameraInfo::deviceName() const
+{
+    return d->deviceName;
+}
+
+/*!
+    Returns the human-readable description of the camera.
+*/
+QString QCameraInfo::description() const
+{
+    return d->description;
+}
+
+/*!
+    Returns the physical position of the camera on the hardware system.
+*/
+QCamera::Position QCameraInfo::position() const
+{
+    return d->position;
+}
+
+/*!
+    Returns the physical orientation of the camera sensor.
+
+    The value is the orientation angle (clockwise, in steps of 90 degrees) of the camera sensor
+    in relation to the display in its natural orientation.
+
+    You can show the camera image in the correct orientation by rotating it by this value in the
+    anti-clockwise direction.
+
+    For example, suppose a mobile device which is naturally in portrait orientation. The back-facing
+    camera is mounted in landscape. If the top side of the camera sensor is aligned with the
+    right edge of the screen in natural orientation, the value should be 270. If the top side of a
+    front-facing camera sensor is aligned with the right of the screen, the value should be 90.
+*/
+int QCameraInfo::orientation() const
+{
+    return d->orientation;
+}
+
+/*!
+    Returns the default camera on the system.
+
+    The returned object should be checked using isNull() before being used, in case there is no
+    default camera or no cameras at all.
+
+    \sa availableCameras()
+*/
+QCameraInfo QCameraInfo::defaultCamera()
+{
+    return QCameraInfo(QMediaServiceProvider::defaultServiceProvider()->defaultDevice(Q_MEDIASERVICE_CAMERA));
+}
+
+/*!
+    Returns a list of available cameras on the system which are located at \a position.
+
+    If \a position is not specified or if the value is QCamera::UnspecifiedPosition, a list of
+    all available cameras will be returned.
+*/
+QList<QCameraInfo> QCameraInfo::availableCameras(QCamera::Position position)
+{
+    QList<QCameraInfo> cameras;
+
+    const QMediaServiceProvider *provider = QMediaServiceProvider::defaultServiceProvider();
+    const QByteArray service(Q_MEDIASERVICE_CAMERA);
+    const QList<QByteArray> devices = provider->devices(service);
+    for (int i = 0; i < devices.count(); ++i) {
+        const QByteArray &name = devices.at(i);
+        if (position == QCamera::UnspecifiedPosition
+                || position == provider->cameraPosition(name)) {
+            cameras.append(QCameraInfo(name));
+        }
+    }
+
+    return cameras;
+}
+
+/*!
+    Sets the QCameraInfo object to be equal to \a other.
+*/
+QCameraInfo& QCameraInfo::operator=(const QCameraInfo& other)
+{
+    d = other.d;
+    return *this;
+}
+
+/*!
+    \fn QCameraInfo::operator!=(const QCameraInfo &other) const
+
+    Returns true if this QCameraInfo is different from \a other.
+*/
+
+#ifndef QT_NO_DEBUG_STREAM
+QDebug operator<<(QDebug d, const QCameraInfo &camera)
+{
+    d.maybeSpace() << QStringLiteral("QCameraInfo(deviceName=%1, position=%2, orientation=%3)")
+                          .arg(camera.deviceName())
+                          .arg(QString::fromLatin1(QCamera::staticMetaObject.enumerator(QCamera::staticMetaObject.indexOfEnumerator("Position"))
+                               .valueToKey(camera.position())))
+                          .arg(camera.orientation());
+    return d.space();
+}
+#endif
+
+QT_END_NAMESPACE