| Index: chrome/common/extensions/docs/server2/templates/intros/ttsEngine.html
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| diff --git a/chrome/common/extensions/docs/server2/templates/intros/ttsEngine.html b/chrome/common/extensions/docs/server2/templates/intros/ttsEngine.html
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| index 086d7c02c01501db97d6cf001485fcf7391d35fd..7f2af21e5188c5c65c26dd9ae460800a843c9b52 100644
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| --- a/chrome/common/extensions/docs/server2/templates/intros/ttsEngine.html
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| +++ b/chrome/common/extensions/docs/server2/templates/intros/ttsEngine.html
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| @@ -9,7 +9,10 @@ module to generate speech. Your extension can then use any available
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| web technology to synthesize and output the speech, and send events back
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| to the calling function to report the status.
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| </p>
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| +
|
| +
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| <h2 id="overview">Overview</h2>
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| +
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| <p>An extension can register itself as a speech engine. By doing so, it
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| can intercept some or all calls to functions such as
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| <a href="tts.html#method-speak"><code>speak()</code></a> and
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| @@ -20,10 +23,13 @@ to provide speech, including streaming audio from a server, HTML5 audio,
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| Native Client, or Flash. An extension could even do something different
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| with the utterances, like display closed captions in a pop-up window or
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| send them as log messages to a remote server.</p>
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| +
|
| <h2 id="manifest">Manifest</h2>
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| +
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| <p>To implement a TTS engine, an extension must
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| declare the "ttsEngine" permission and then declare all voices
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| it provides in the extension manifest, like this:</p>
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| +
|
| <pre>{
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| "name": "My TTS Engine",
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| "version": "1.0",
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| @@ -45,15 +51,19 @@ it provides in the extension manifest, like this:</p>
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| },</b>
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| "background_page": "background.html",
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| }</pre>
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| +
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| <p>An extension can specify any number of voices.</p>
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| +
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| <p>The <code>voice_name</code> parameter is required. The name should be
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| descriptive enough that it identifies the name of the voice and the
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| engine used. In the unlikely event that two extensions register voices
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| with the same name, a client can specify the ID of the extension that
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| should do the synthesis.</p>
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| +
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| <p>The <code>gender</code> parameter is optional. If your voice corresponds
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| to a male or female voice, you can use this parameter to help clients
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| choose the most appropriate voice for their application.</p>
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| +
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| <p>The <code>lang</code> parameter is optional, but highly recommended.
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| Almost always, a voice can synthesize speech in just a single language.
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| When an engine supports more than one language, it can easily register a
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| @@ -62,11 +72,13 @@ voice can handle more than one language, it's easiest to just list two
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| separate voices and handle them using the same logic internally. However,
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| if you want to create a voice that will handle utterances in any language,
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| leave out the <code>lang</code> parameter from your extension's manifest.</p>
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| +
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| <p>Finally, the <code>event_types</code> parameter is required if the engine can
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| send events to update the client on the progress of speech synthesis.
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| At a minimum, supporting the <code>'end'</code> event type to indicate
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| when speech is finished is highly recommended, otherwise Chrome cannot
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| schedule queued utterances.</p>
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| +
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| <p class="note">
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| <strong>Note:</strong> If your TTS engine does not support
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| the <code>'end'</code> event type, Chrome cannot queue utterances
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| @@ -76,8 +88,10 @@ option to your engine's onSpeak handler, giving you the option of
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| implementing your own queueing. This is discouraged because then
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| clients are unable to queue utterances that should get spoken by different
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| speech engines.</p>
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| +
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| <p>The possible event types that you can send correspond to the event types
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| that the <code>speak()</code> method receives:</p>
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| +
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| <ul>
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| <li><code>'start'</code>: The engine has started speaking the utterance.
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| <li><code>'word'</code>: A word boundary was reached. Use
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| @@ -94,34 +108,45 @@ that the <code>speak()</code> method receives:</p>
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| this utterance cannot be spoken.
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| Pass more information in <code>event.errorMessage</code>.
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| </ul>
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| +
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| <p>The <code>'interrupted'</code> and <code>'cancelled'</code> events are
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| not sent by the speech engine; they are generated automatically by Chrome.</p>
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| +
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| <p>Text-to-speech clients can get the voice information from your
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| extension's manifest by calling
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| <a href="tts.html#method-getVoices">getVoices()</a>,
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| assuming you've registered speech event listeners as described below.</p>
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| +
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| <h2 id="handling_speech_events">Handling speech events</h2>
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| +
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| <p>To generate speech at the request of clients, your extension must
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| register listeners for both <code>onSpeak</code> and <code>onStop</code>,
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| like this:</p>
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| +
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| <pre>var speakListener = function(utterance, options, sendTtsEvent) {
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| sendTtsEvent({'event_type': 'start', 'charIndex': 0})
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| +
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| // (start speaking)
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| +
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| sendTtsEvent({'event_type': 'end', 'charIndex': utterance.length})
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| };
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| +
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| var stopListener = function() {
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| // (stop all speech)
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| };
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| +
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| chrome.ttsEngine.onSpeak.addListener(speakListener);
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| chrome.ttsEngine.onStop.addListener(stopListener);</pre>
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| +
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| <p class="warning">
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| <b>Important:</b>
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| If your extension does not register listeners for both
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| <code>onSpeak</code> and <code>onStop</code>, it will not intercept any
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| speech calls, regardless of what is in the manifest.</p>
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| +
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| <p>The decision of whether or not to send a given speech request to an
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| extension is based solely on whether the extension supports the given voice
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| parameters in its manifest and has registered listeners
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| for <code>onSpeak</code> and <code>onStop</code>. In other words,
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| there's no way for an extension to receive a speech request and
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| -dynamically decide whether to handle it.</p>
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| +dynamically decide whether to handle it.</p>
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|
|