文字轉語音

Text To Speech

A Flutter plugin provides TTS (Text-To-Speech) Service. This plugin aims to offer the most of TTS API feature from iOS, Android, web, and macOS.

Getting Started

To use this plugin, add text_to_speech as a dependency in your pubspec.yaml file:

dependencies:  
  text_to_speech: ^0.2.3

Installation

Android

• Minimum SDK version: 21
• Applications targeting SDK 30 (Android 11) need to declare TextToSpeech.Engine.INTENT_ACTION_TTS_SERVICE in the queries elements of Android Manifest (See Android documentation).

<queries>  
  <intent>  
      <action android:name="android.intent.action.TTS_SERVICE" />  
  </intent>  
 </queries>  

iOS & macOS

• iOS minimum version: 7.0
• macOs minimum version 10.14

(See Apple documentation).

Features

Feature	Android	iOS	Web	macOS
speak	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:
stop	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:
pause	-	:white_check_mark:	:white_check_mark:	:white_check_mark:
resume	-	:white_check_mark:	:white_check_mark:	:white_check_mark:
set volume	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:
set rate	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:
set pitch	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:
set language	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:
get language	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:
get voice	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:

Usages

To start, import the dependency in your code:

import 'package:text_to_speech/text_to_speech.dart';  

Then, create instance of TextToSpeech class:

TextToSpeech tts = TextToSpeech();  

Speak

String text = "Hello, Good Morning!";  
tts.speak(text);  

Set Volume

Volume range: 0-1 where 0 is silence, and 1 is the maximum volume (the default behavior).

double volume = 1.0;  
tts.setVolume(volume);  

Set Rate

Rate range: 0-2.
1.0 is the normal and default speech rate. Lower values slow down the speech (0.5 is half the normal speech rate). Greater values accelerate it (2.0 is twice the normal speech rate).

double rate = 1.0;  
tts.setRate(rate);  

Set Pitch

Pitch range: 0-2.
1.0 is the normal pitch, lower values lower the tone of the synthesized voice, greater values increase it.

double pitch = 1.0;  
tts.setPitch(pitch);  

Set Language

Accepting locale tag name of specific language, e.g. 'en-US'. You can retrieve list of supported language using getLanguage function.

String language = 'en-US';  
tts.setLanguage(language);  

Get Languages

Provide list of supported language codes in locale tag name format, e.g. 'en-US'. You can get display name for specific language code

String language = 'en-US';  
tts.setLanguage(language);  

Get Voice

We can get all available voices or get voices of specific language. This function will returns particular voice name.

List<String> voices = await tts.getVoices();  
  
String language = 'en-US';  
List<String> voices = await tts.getVoiceByLang(language);  

Native API Reference

• Android TTS API: https://developer.android.com/reference/android/speech/tts/TextToSpeech
• iOS/macOS AVSpeechSynthesizer API: https://developer.apple.com/documentation/avfaudio/avspeechsynthesizer
• Web Speech API: https://dvcs.w3.org/hg/speech-api/raw-file/tip/speechapi.html#tts-section

Example

You can find example in the example folder and run it to check the implementation.
Move to example directory:

$ cd example  

Run Android / iOS

$ flutter run -d <device_name>  

Run Web

$ flutter run -d chrome  

Run macOS

$ flutter run -d macOS  

TODO

• [ ] Utterance Status Listener
• [ ] Linux Implementation
• [ ] Windows Implementation