Phonon::BackendInterface Class Reference

#include <phonon/BackendInterface>

Public Types
enum	Class {   MediaObjectClass , VolumeFaderEffectClass , AudioOutputClass , AudioDataOutputClass ,   VisualizationClass , VideoDataOutputClass , EffectClass , VideoWidgetClass ,   VideoGraphicsObjectClass }

Public Member Functions
virtual	~BackendInterface ()
virtual QStringList	availableMimeTypes () const =0
virtual bool	connectNodes (QObject *, QObject *)=0
virtual QObject *	createObject (Class c, QObject *parent, const QList< QVariant > &args=QList< QVariant >())=0
virtual bool	disconnectNodes (QObject *, QObject *)=0
virtual bool	endConnectionChange (QSet< QObject * >)=0
virtual QList< int >	objectDescriptionIndexes (ObjectDescriptionType type) const =0
virtual QHash< QByteArray, QVariant >	objectDescriptionProperties (ObjectDescriptionType type, int index) const =0
virtual bool	startConnectionChange (QSet< QObject * >)=0

Detailed Description

Main Backend class interface.

This interface defines the main factory of the backend. The createObject function creates all the objects needed by the frontend.

The objectDescriptionIndexes and objectDescriptionProperties functions return information about available devices, effects and codecs.

An implementation could look like this:

QObject *Backend::createObject(BackendInterface::Class c, QObject *parent, const QList<QVariant> &args)
{
    switch (c) {
    case MediaObjectClass:
        return new MediaObject(parent);
    case VolumeFaderEffectClass:
        return new VolumeFaderEffect(parent);
    case AudioOutputClass:
        return new AudioOutput(parent);
    case AudioDataOutputClass:
        return new AudioDataOutput(parent);
    case VisualizationClass:
        return new Visualization(parent);
    case VideoDataOutputClass:
        return new VideoDataOutput(parent);
    case EffectClass:
        return new Effect(args[0].toInt(), parent);
    case VideoWidgetClass:
        return new VideoWidget(qobject_cast<QWidget *>(parent));
    }
    return 0;
}
 
QSet<int> Backend::objectDescriptionIndexes(ObjectDescriptionType type) const
{
    QSet<int> set;
    switch(type)
    {
    case Phonon::AudioOutputDeviceType:
        // use AudioDeviceEnumerator to list ALSA and OSS devices
        set << 10000 << 10001;
        break;
    case Phonon::AudioCaptureDeviceType:
        set << 20000 << 20001;
        break;
    case Phonon::VideoOutputDeviceType:
        break;
    case Phonon::VideoCaptureDeviceType:
        set << 30000 << 30001;
        break;
    case Phonon::VisualizationType:
    case Phonon::AudioCodecType:
    case Phonon::VideoCodecType:
    case Phonon::ContainerFormatType:
        break;
    case Phonon::EffectType:
        set << 0x7F000001;
        break;
    }
    return set;
}
 
QHash<QByteArray, QVariant> Backend::objectDescriptionProperties(ObjectDescriptionType type, int index) const
{
    QHash<QByteArray, QVariant> ret;
    switch (type) {
    case Phonon::AudioOutputDeviceType:
        switch (index) {
        case 10000:
            ret.insert("name", QLatin1String("internal Soundcard"));
            break;
        case 10001:
            ret.insert("name", QLatin1String("USB Headset"));
            ret.insert("icon", KIcon("usb-headset"));
            ret.insert("available", false);
            break;
        }
        break;
    case Phonon::AudioCaptureDeviceType:
        switch (index) {
        case 20000:
            ret.insert("name", QLatin1String("Soundcard"));
            ret.insert("description", QLatin1String("first description"));
            break;
        case 20001:
            ret.insert("name", QLatin1String("DV"));
            ret.insert("description", QLatin1String("second description"));
            break;
        }
        break;
    case Phonon::VideoOutputDeviceType:
        break;
    case Phonon::VideoCaptureDeviceType:
        switch (index) {
        case 30000:
            ret.insert("name", QLatin1String("USB Webcam"));
            ret.insert("description", QLatin1String("first description"));
            break;
        case 30001:
            ret.insert("name", QLatin1String("DV"));
            ret.insert("description", QLatin1String("second description"));
            break;
        }
        break;
    case Phonon::VisualizationType:
        break;
    case Phonon::AudioCodecType:
        break;
    case Phonon::VideoCodecType:
        break;
    case Phonon::ContainerFormatType:
        break;
    case Phonon::EffectType:
        switch (index) {
        case 0x7F000001:
            ret.insert("name", QLatin1String("Delay"));
            ret.insert("description", QLatin1String("Simple delay effect with time, feedback and level controls."));
            break;
        }
        break;
    }
    return ret;
}

Author

Matthias Kretz kretz.nosp@m.@kde.nosp@m..org

Definition at line 166 of file backendinterface.h.

Member Enumeration Documentation

Class

enum Phonon::BackendInterface::Class

Classes that the createObject function has to handle.

Enumerator
MediaObjectClass	Request to return a MediaObject object.
VolumeFaderEffectClass	Request to return a VolumeFaderEffect object.
AudioOutputClass	Request to return a AudioOutput object.
AudioDataOutputClass	Request to return a AudioDataOutput object.
VisualizationClass	Request to return a Visualization object.
VideoDataOutputClass	Request to return a VideoDataOutput object.
EffectClass	Request to return a Effect object. Takes an additional int that specifies the effect Id.
VideoWidgetClass	Request to return a VideoWidget object.

Definition at line 179 of file backendinterface.h.

Constructor & Destructor Documentation

~BackendInterface()

virtual Phonon::BackendInterface::~BackendInterface ( )

inlinevirtual

Silence gcc's warning.

Definition at line 174 of file backendinterface.h.

Member Function Documentation

availableMimeTypes()

virtual QStringList Phonon::BackendInterface::availableMimeTypes ( ) const

pure virtual

gets all available mime types

connectNodes()

virtual bool Phonon::BackendInterface::connectNodes ( QObject * , QObject *  )

pure virtual

Defines a signal connection between the two given nodes.

createObject()

virtual QObject * Phonon::BackendInterface::createObject ( Class c, QObject * parent, const QList< QVariant > & args = QList< QVariant >() )

pure virtual

Returns a new instance of the requested class.

Parameters

c	The requested class.
parent	The parent object.
args	Additional arguments (documented in Class).

disconnectNodes()

virtual bool Phonon::BackendInterface::disconnectNodes ( QObject * , QObject *  )

pure virtual

Cuts a signal connection between the two given nodes.

endConnectionChange()

virtual bool Phonon::BackendInterface::endConnectionChange ( QSet< QObject * > )

pure virtual

When this function is called the nodes given in the parameter list may lose signal data when a port is not connected.

objectDescriptionIndexes()

virtual QList< int > Phonon::BackendInterface::objectDescriptionIndexes ( ObjectDescriptionType type ) const

pure virtual

Returns the unique identifiers for the devices/effects/codecs of the given type.

Parameters

type	see ObjectDescriptionType

objectDescriptionProperties()

virtual QHash< QByteArray, QVariant > Phonon::BackendInterface::objectDescriptionProperties ( ObjectDescriptionType type, int index ) const

pure virtual

Given a unique identifier that was returned from objectDescriptionIndexes this function returns a hash mapping property names to values.

The property "name" must always be present. All other properties are optional.

List of possible properties:

• name: The name of the device/effect/codec/...
• description: A text explaining what this device/effect/codec/... is/can do
• icon: An icon name (using the freedesktop naming scheme) or a QIcon for this device/effect/codec/...
• available: A bool telling whether the device is present or unplugged.

Parameters

type	see ObjectDescriptionType
index	The unique identifier that is returned from objectDescriptionIndexes

startConnectionChange()

virtual bool Phonon::BackendInterface::startConnectionChange ( QSet< QObject * > )

pure virtual

When this function is called the nodes given in the parameter list should not lose any signal data when connections are changed.

---

The documentation for this class was generated from the following file:

• backendinterface.h