語音合成API突出顯示語音

Question

目前，我正在制作一個簡單的應用，其中使用語音合成API朗讀文本。 我想在說出（粗體）這兩個詞時將其突出顯示。 我目前有一個非常基本的實現，使用“ onboundary”事件來執行此操作。 但是，我想知道是否有更好/更完善的方法，因為我的實現基於一些假設。

var words;
var wordIdx;
var text;
var utterance = new SpeechSynthesisUtterance();
utterance.lang = 'en-UK';
utterance.rate = 1;

window.onload = function(){
    document.getElementById('textarea').innerText = 'This is a text area.  It is used as a simple test to check whether these words are highlighted as they are spoken using the web speech synthesis API (utterance).';

    document.getElementById('playbtn').onclick = function(){
        text    = document.getElementById('textarea').innerText;
        words   = text.split(' ');
        wordIdx = 0;

        utterance.text = text;
        speechSynthesis.speak(utterance);
    }

    utterance.onboundary = function(event){
        var e = document.getElementById('textarea');
        var it = '';

        for(var i = 0; i < words.length; i++){
            if(i === wordIdx){
                it += '<strong>' + words[i] + '</strong>';
            } else {
                it += words[i];
            }

            it += ' ';
        }

        e.innerHTML = it;
        wordIdx++;
    }
}

Answer 1

您的代碼不起作用，但是我只是寫了一個示例，該示例可以按您想要的方式工作。 打開小提琴以查看其工作原理

var utterance = new SpeechSynthesisUtterance();
var wordIndex = 0;
var global_words = [];
utterance.lang = 'en-UK';
utterance.rate = 1;


document.getElementById('playbtn').onclick = function(){
    var text    = document.getElementById('textarea').value;
    var words   = text.split(" ");
    global_words = words;
    // Draw the text in a div
    drawTextInPanel(words);
    spokenTextArray = words;
    utterance.text = text;
    speechSynthesis.speak(utterance);
};

utterance.onboundary = function(event){
    var e = document.getElementById('textarea');
    var word = getWordAt(e.value,event.charIndex);
    // Show Speaking word : x
    document.getElementById("word").innerHTML = word;
    //Increase index of span to highlight
    console.info(global_words[wordIndex]);

    try{
        document.getElementById("word_span_"+wordIndex).style.color = "blue";
    }catch(e){}

    wordIndex++;
};

utterance.onend = function(){
        document.getElementById("word").innerHTML = "";
    wordIndex = 0;
    document.getElementById("panel").innerHTML = "";
};

// Get the word of a string given the string and the index
function getWordAt(str, pos) {
    // Perform type conversions.
    str = String(str);
    pos = Number(pos) >>> 0;

    // Search for the word's beginning and end.
    var left = str.slice(0, pos + 1).search(/\S+$/),
        right = str.slice(pos).search(/\s/);

    // The last word in the string is a special case.
    if (right < 0) {
        return str.slice(left);
    }
    // Return the word, using the located bounds to extract it from the string.
    return str.slice(left, right + pos);
}

function drawTextInPanel(words_array){
console.log("Dibujado");
        var panel = document.getElementById("panel");
    for(var i = 0;i < words_array.length;i++){
        var html = '<span id="word_span_'+i+'">'+words_array[i]+'</span>&nbsp;';
        panel.innerHTML += html;
    }
}

請玩以下小提琴：

高亮口語SpeechSynthesis Javascript小提琴

它以藍色突出顯示div中的口語單詞，您可以使用粗體樣式對其進行自定義，但重要的是創意。

注意：請記住， onboundary事件僅針對本機（本地）語音合成觸發。 更改Google遠程語音的Google示例中指定的語音（即Google UK English Male ），將使您的代碼失敗，因為SpeechSynthesis API似乎僅播放由Google服務器生成的聲音。