osmscout::TTSEngine Class Reference

Abstract text-to-speech engine. More...

#include <TTSEngine.h>

Inheritance diagram for osmscout::TTSEngine:

Public Types
enum class	TTSEngineState { Idle , Initializing , Synthesizing , Error }
	State of a TTSEngine, useful for showing synthesis progress in the UI (initial synthesis of a message may take a noticeable amount of time). More...

Public Slots
virtual void	initVoice (const Voice &voice)=0
	Initialize the engine for the given voice.
virtual void	playMessage (QString message)=0
	Prepare the message (when it is not cached yet) and play it right away.
virtual void	prepareMessage (QString message)=0
	Synthesize the message to an audio file (cached in a temporary directory) without playing it.

Signals
void	error (const QString &message)
	Emitted when the engine encounters an error (e.g.
void	playAudioFilesRequest (const QList< QUrl > &audioFiles)
void	stateChange (TTSEngineState state)
	Emitted whenever the engine's state changes, e.g.

Public Member Functions
TTSEngineState	getState () const
virtual Voice	getVoice ()=0
TTSEngine &	operator= (const TTSEngine &)=delete
TTSEngine &	operator= (TTSEngine &&)=delete
	Q_ENUM (TTSEngineState)
	TTSEngine ()
	TTSEngine (const TTSEngine &)=delete
	TTSEngine (TTSEngine &&)=delete
	~TTSEngine () override

Protected Member Functions
virtual void	cleanCache ()
	Called on the engine thread when the background thread starts.

Protected Attributes
QThread *	thread
	engine background thread (owns itself, deleted on finish)

Properties
TTSEngineState	state {TTSEngineState::Idle}
	current state of the engine

Detailed Description

Abstract text-to-speech engine.

It synthesizes spoken navigation instructions and plays them through the provided VoiceCorePlayer.

Speech synthesis may be a slow, synchronous operation (see PiperTTSEngine), so the engine runs in its own background thread. All operations (initVoice, prepareMessage, playMessage) are executed asynchronously on that thread, they should be invoked through a queued connection (e.g. QMetaObject::invokeMethod with Qt::QueuedConnection).

The background thread is created and started by the base constructor. When it starts, cleanCache() is invoked on the engine thread (default implementation is empty, a derived class may override it to prune its cache).

Member Enumeration Documentation

TTSEngineState

enum class osmscout::TTSEngine::TTSEngineState

strong

State of a TTSEngine, useful for showing synthesis progress in the UI (initial synthesis of a message may take a noticeable amount of time).

Enumerator
Idle	engine is idle, not synthesizing anything at the moment
Initializing	engine is initializing the voice (e.g. loading a model)
Synthesizing	engine is currently synthesizing a message
Error	the last operation failed (see TTSEngine::error signal for details)

Constructor & Destructor Documentation

TTSEngine() [1/3]

osmscout::TTSEngine::TTSEngine

(

)

References cleanCache(), and thread.

TTSEngine() [2/3]

osmscout::TTSEngine::TTSEngine ( const TTSEngine &  )

delete

TTSEngine() [3/3]

osmscout::TTSEngine::TTSEngine ( TTSEngine &&  )

delete

~TTSEngine()

osmscout::TTSEngine::~TTSEngine ( )

override

References thread.

Member Function Documentation

cleanCache()

void osmscout::TTSEngine::cleanCache ( )

protectedvirtual

Called on the engine thread when the background thread starts.

The default implementation does nothing; a derived class may override it to clean up its on-disk cache. Runs on the engine thread.

Reimplemented in osmscout::PiperTTSEngine.

Referenced by TTSEngine().

error

void osmscout::TTSEngine::error ( const QString &  message )

signal

Emitted when the engine encounters an error (e.g.

synthesis or voice loading failure). message is a localized, human readable description suitable for direct display in the UI.

Referenced by osmscout::PiperTTSEngine::initVoice().

getState()

TTSEngineState osmscout::TTSEngine::getState ( ) const

inline

getVoice()

virtual Voice osmscout::TTSEngine::getVoice ( )

pure virtual

Implemented in osmscout::PiperTTSEngine.

Referenced by osmscout::InstalledVoicesModel::playTTSSample().

initVoice

virtual void osmscout::TTSEngine::initVoice ( const Voice &  voice )

pure virtualslot

Initialize the engine for the given voice.

Runs asynchronously on the engine thread.

Implemented in osmscout::PiperTTSEngine.

operator=() [1/2]

TTSEngine & osmscout::TTSEngine::operator= ( const TTSEngine &  )

delete

operator=() [2/2]

TTSEngine & osmscout::TTSEngine::operator= ( TTSEngine &&  )

delete

playAudioFilesRequest

void osmscout::TTSEngine::playAudioFilesRequest ( const QList< QUrl > &  audioFiles )

signal

Referenced by osmscout::PiperTTSEngine::playMessage().

playMessage

virtual void osmscout::TTSEngine::playMessage ( QString  message )

pure virtualslot

Prepare the message (when it is not cached yet) and play it right away.

Runs asynchronously on the engine thread.

Implemented in osmscout::PiperTTSEngine.

prepareMessage

virtual void osmscout::TTSEngine::prepareMessage ( QString  message )

pure virtualslot

Synthesize the message to an audio file (cached in a temporary directory) without playing it.

Runs asynchronously on the engine thread.

Implemented in osmscout::PiperTTSEngine.

Q_ENUM()

osmscout::TTSEngine::Q_ENUM

(

TTSEngineState

)

stateChange

void osmscout::TTSEngine::stateChange ( TTSEngineState  state )

signal

Emitted whenever the engine's state changes, e.g.

when it starts or finishes synthesizing a message. Useful for showing synthesis progress in the UI, as the initial synthesis of a message may take a while.

Referenced by osmscout::PiperTTSEngine::initVoice().

Member Data Documentation

thread

QThread* osmscout::TTSEngine::thread

protected

engine background thread (owns itself, deleted on finish)

Referenced by TTSEngine(), and ~TTSEngine().

Property Documentation

state

TTSEngineState osmscout::TTSEngine::state {TTSEngineState::Idle}

read

current state of the engine

Referenced by osmscout::PiperTTSEngine::initVoice().

---

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

• TTSEngine.h
• TTSEngine.cpp