/// <summary>
/// 获取章节语音
/// </summary>
/// <param name="chapter">章节</param>
/// <param name="setCurrentChapter">是否将其设置为当前章节</param>
/// <param name="synthesizer">语音合成器</param>
/// <returns></returns>
public async Task <MediaPlaybackItem> GetChapterVoiceAsync(Chapter chapter, bool setCurrentChapter = false, SpeechSynthesizer synthesizer = null)
{
if (Chapters.Count == 0)
{
throw new InvalidCastException("Chapter not loaded");
}
else if (chapter == null || !Chapters.Contains(chapter))
{
throw new ArgumentException("The chapter is not in current book");
}
// 将章节转化为语音合成流需要时间和额外的系统资源，不宜生成超量的文本
string content = GetReadText(chapter);
if (content.Length > SpeechMaxLength)
{
throw new Exception("The chapter detail text length is too large");
}
if (CurrentChapter != chapter)
{
LoadChapter(chapter);
}
// 控件原本是按需加载页面，但考虑到用户会对生成的语音流进行进度调整，所以在生成合成语音时会将当前章节未渲染的部分全部渲染
_readerView.RenderAllOverflows();
bool isTempSyn = false;
if (synthesizer == null)
{
synthesizer = new SpeechSynthesizer();
isTempSyn = true;
}
synthesizer.Options.IncludeSentenceBoundaryMetadata = true;
synthesizer.Options.IncludeWordBoundaryMetadata = true;
var stream = await synthesizer.SynthesizeTextToStreamAsync(content);
_tempSpeechStream = stream;
MediaSource source = MediaSource.CreateFromStream(stream, stream.ContentType);
if (isTempSyn)
{
synthesizer.Dispose();
}
var playback = new MediaPlaybackItem(source);
RegisterForWordBoundaryEvents(playback);
return(playback);
}
