使用JavaScript平滑地更改文本

Question

我正在制作一个着陆页,其中一个短语随着选择的单词不断变化.例如,

为客户设计更好的网站.

将切换第一个或最后一个词成为

为客户开发更好的网站.

但是,由于"开发"是一个比"设计"更大的词,因此文本的其余部分最终会被推到而没有平滑过渡.请记住,这是一个多行句子,它是居中的.

var first  = ['Create','Design','Develop'];
var second = ['you','clients','artists','us'];
var i = 0;
var j = 0;
var maxfirst  = first.length - 1;
var maxsecond = second.length - 1;

function delay() {
    $('#intro').velocity("transi1ion.slideUpIn", 1250);
    setInterval(firstwordchange, 400);
    setInterval(secondwordchange, 500);
}

function firstwordchange() {
    if (i < maxfirst) i++; else i = 0;

    $('#firstword').velocity("transition.slideUpOut", 300);

    setTimeout(function () {
        $('#firstword').text(first[i]);
    }, 200);

  $('#firstword').velocity("transition.slideUpIn", 300);
}

function secondwordchange() {
    if (j < maxsecond) j++; else j = 0;

    $('#secondword').velocity("transition.slideUpOut", 300);

    setTimeout(function () {
        $('#secondword').text(second[j]);
    }, 200);

    $('#secondword').velocity("transition.slideUpIn", 300);
}

setTimeout(delay, 700);

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.6.4/jquery.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/velocity/1.1.0/velocity.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/velocity/1.1.0/velocity.ui.min.js"></script>
<div id="intro">
    <span id="firstword" class="introchange">Create</span>
    better websites made for
    <span id="secondword" class="introchange">you</span>.
</div>

如何使内部的,不变的文本过渡顺利进行？

(这里的实际网站)

Answer 1

我要写一篇关于我的概述 会做 做到了:

1. 使用默认初始值为更改单词和静态定位渲染句子.
2. 还可以渲染其他单词变体,visibility: hidden以便您可以确定它们的大小.
3. 绝对每个句子部分.从这一点开始,一切都将被绝对定位,所以如果你有一个很好的定位环境(通常position: relative在父母身上完成),那么它是最好的.
4. 测量每个句子部分,包括改变单词和固定句子部分的宽度,包括隐藏的部分.
5. 更改单词时,计算旧尺寸和新尺寸之间的差异.基于这些差异,使用一些非常简单的数学来查看应该向左或向右移动多少部分并在它们上应用水平翻译(当然还要为翻译设置动画 - 可能只是为了你想要左/右移动,也许你想要其他改变单词的效果).

演示:

var first = ['Create','Cut','Reticulate'];
var second = ['you','clients','artists','us'];
var firstM = [], secondM = [], el;

var $first = $('.the-first'); 
var $second = $('.the-second'); 
var $container = $('#container');

// init static //    
$first.text(first[0]);
$second.text(second[0]);

// create measurables //
for(var i = 0; i < first.length; i++){
    el = $('<div class="measurable">' + first[i] + '</div>');
    $container.append(el);
    firstM.push(el.width());
}
for(var i = 0; i < second.length; i++){
    el = $('<div class="measurable">' + second[i] + '</div>');
    $container.append(el);
    secondM.push(el.width());
}

// absolutize //
var positions = [];
$('#container > span').each(function(){
    positions.push($(this).position());
});
$('#container > span').each(function(){
    var pos = positions.shift();
    $(this).css({
        position: 'absolute',
        left: pos.left,
        top: pos.top
    });
});

// remember initial sizes //
var firstInitialWidth = $first.width();
var secondInitialWidth = $second.width();

// loop the loop //
var activeWordsIndex = 0;
setInterval(function(){
    activeWordsIndex++;
    var firstIndex = activeWordsIndex % first.length;
    var secondIndex = activeWordsIndex % second.length;
    
    $first.text( first[firstIndex] );
    $second.text( second[secondIndex] );
    
    var firstLineOffset = (firstM[firstIndex] - firstInitialWidth) / 2;
    var secondLineOffset = (secondM[secondIndex] - secondInitialWidth) / 2;
   
    $('.static.first').css({
        transform: 'translateX(' + firstLineOffset + 'px)'
    });
    $('.static.second').css({
        transform: 'translateX(' + (-secondLineOffset) + 'px)'
    });
    
    $first.css({
        transition: 'none', 
        transform: 'translate(' + (-firstLineOffset) + 'px, -30px)',
        opacity: '0'
    });
    setTimeout(function(){
        $first.css({
            transition: 'all 1s ease',
            transform: 'translate(' + (-firstLineOffset) + 'px, 0px)',
            opacity: '1'
        });
    }, 50);
    
    $second.css({
        transition: 'none', 
        transform: 'translate(' + (-secondLineOffset) + 'px, 30px)',
        opacity: '0'
    });
    setTimeout(function(){
        $second.css({
            transition: 'all 1s ease',
            transform: 'translate(' + (-secondLineOffset) + 'px, 0px)',
            opacity: '1'
        });
    }, 50);
}, 2000);

#ubercontainer {
    border: 1px solid #eaeaea;
    border-radius: 2px;
    background-color: #ffefc6;
    width: 500px;
    margin: 20px auto;
    padding: 30px 0;
}
#container {
    position: relative;
    text-align: center;
    font-family: sans-serif;
    font-size: 32px;
    font-weight: 800;
    color: #4a6b82;
    height: 78px;
}
.measurable {
    position: absolute;
    visibility: hidden;
}

.static.first, .static.second {
    transition: transform 1s ease;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="ubercontainer">
<div id="container">
    <span class="the-first"></span> 
    <span class="static first">better websites </span><br />
    <span class="static second">made for</span> 
    <span class="the-second"></span>
</div>
</div>

Answer 2

写一个像这样的解决方案,你很快就会意识到,如果你的单词的长度差异合理,你将不得不放弃动态换行的想法.

除了这个小细节之外,你可以轻松地实现使用jQuery动画回调地狱的标准金字塔之后的效果:

var target = $('#target');
var change = function(str) {
  var tmp = $('<h1>' + str + '</h1>');
  tmp.css({
      display: "inline-block",
      position: "absolute"
    })
    .appendTo('body')
    .hide();
  var targetWidth = tmp.outerWidth();
  tmp.remove();
  target.animate({
    opacity: 0
  }, 200, function() {
    target.animate({
      width: targetWidth
    }, 300, function() {
      target.empty()
        .html(str)
        .css({
          display: "initial"
        })
        .animate({
          opacity: 1
        }, 200);
    });
  });
}
var samples = [
  "some sample",
  "another example",
  "just"
];
var i = 0;
setInterval(function() {
  change(samples[++i % samples.length]);
}, 1400);

.container {
  margin: 0 auto;
  text-align: center;
}
#target {
  display: inline-block;
  vertical-align: bottom;
  white-space: no-wrap;
  height: 1em;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="container">
  <h1>This is <span id="target"></span> text</h1>
  <h1>in a longer sentence</h1>
</div>