使用引导程序文本转盘淡入淡出背景

Question

我有三个背景图像，我想每隔5秒淡出一次。我还利用原生引导转盘组件以5秒的间隔滑入和滑出文本，以与不断变化和褪色的背景图像相匹配。

场景

• 问题1：第一个背景图像将是页面加载时的默认背景图像。5秒后，第二个背景图像会褪色，这也与转盘滑动到第二个文本的时间一致。又过了5秒，第三个背景图像逐渐消失，转盘滑动到下一个文本。

• 问题2：引导程序转盘组件有一个指示器，当单击时，它会切换并滑动到转盘部分的文本中。我希望在单击转盘指示器时更改背景图像。也就是说，如果转盘指示器1被点击，则背景图像应当淡化为第一背景图像。这应当适用于第二和第三转盘指示器及其各自的背景图像。如果背景图像当前是活动的转盘项目和背景图像，则背景图像不应更改并渐变为单击的图像。

现状

• 我已经能够使用jquery实现具有衰落效果的背景图像，我在stackoverflow中也得到了一个解决方案。我还使用bootstrap旋转木马组件完成了文本旋转木马，该组件具有选项(数据间隔="5000"(，该选项将切换时间设置为5秒，以匹配背景图像淡入和淡出的相同时间间隔，但仍有明显的小延迟。如何消除明显的延迟？

• 图像有时会先闪烁后褪色。有没有更好、更合适的方法可以在不闪烁图像的情况下实现褪色效果？

• 即使我在点击时运行了该功能，点击转盘指示器也不会切换并将背景图像淡入下一个。如何以正确的方式实现？

以下是我尝试过的：

var bgImageArray = ["1_ozdgvm.jpg", "2_vjtjfy.jpg", "3_oxpdx2.jpg"],
base = "https://res.cloudinary.com/iolamide/image/upload/v1604569872/home_banner_",
secs = 5;
bgImageArray.forEach(function(img) {
new Image().src = base + img;
// caches images, avoiding white flash between background replacements
});
function backgroundSequence() {
window.clearTimeout();
var k = 0;
for (i = 0; i < bgImageArray.length; i++) {
setTimeout(function() {
document.getElementById('animated-bg').style.backgroundImage = "url(" + base + bgImageArray[k] + ")";
// document.getElementById('animated-bg').style.backgroundSize ="cover";
if ((k + 1) === bgImageArray.length) {
setTimeout(function() {
backgroundSequence()
}, (secs * 1000))
} else {
k++;
}
}, (secs * 1000) * i)
}
}
backgroundSequence();

$('.carousel-item').click(function() {
backgroundSequence();
})

*,
*::before,
*::after {
margin: 0;
padding: 0;
}
html {
box-sizing: border-box;
}
body {
box-sizing: inherit;
color: #fff !important;
}
.animated-bg {
background-image: url("https://res.cloudinary.com/iolamide/image/upload/v1604569872/home_banner_1_ozdgvm.jpg");
background-size: cover;
background-position: center;
background-repeat: no-repeat;
transition: background 1s;
height: 694px;
position: relative;
display: flex;
flex-direction: column;
align-items: center;
justify-content: center;
}
.animated-bg:before {
content: "";
position: absolute;
top: 0;
bottom: 0;
left: 0;
right: 0;
}
.container {
padding: 3rem;
border-radius: 20px;
width: 700px;
background: rgba(0, 0, 0, 0.3);
display: flex;
flex-direction: column;
align-items: center;
justify-content: center;
text-align: center;
}
.text-top p {
width: 400px;
margin: 30px auto;
text-align: center;
}
h1 {
margin-top: 0;
text-align: center;
font-weight: 600;
}
.carousel-item p {
width: 330px;
text-align: center;
}
.carousel-indicators {
bottom: -50px !important;
}
@media only screen and (max-width: 800px) {
.container {
padding: 2rem;
width: 90%;
}
}
@media only screen and (max-width: 500px) {
.text-top p {
width: 80%;
}
}

<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" rel="stylesheet" />
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js"></script>
<div class="animated-bg" id="animated-bg">
<div class="container">
<div class="text-top" id="texttop">
<h1>Crossfade and Text Carousel</h1>
<p>Fade background image and swipe text at the same time. Also fade the background image to the one that matches the carousel's text when the carousel's indicator is clicked</p>
</div>
<div id="carouselExampleIndicators" class="carousel slide" data-ride="carousel" data-interval="5000">
<ol class="carousel-indicators">
<li data-target="#carouselExampleIndicators" data-slide-to="0" class="active"></li>
<li data-target="#carouselExampleIndicators" data-slide-to="1"></li>
<li data-target="#carouselExampleIndicators" data-slide-to="2"></li>
</ol>
<div class="carousel-inner">
<div class="carousel-item active">
<p>
Carousel Text One
</p>
</div>
<div class="carousel-item">
<p>Carousel Text Two</p>
</div>
<div class="carousel-item">
<p>Carousel Text Three</p>
</div>
</div>
</div>
</div>
</div>

Answer 1

您不需要自己切换图像的所有逻辑。您可以使用carousel apion('slide.bs.carousel')收听幻灯片更改，并相应地切换图像。

const bgImageArray = ["1_ozdgvm.jpg", "2_vjtjfy.jpg", "3_oxpdx2.jpg"],
base = "https://res.cloudinary.com/iolamide/image/upload/v1604569872/home_banner_";

bgImageArray.forEach(function(img) {
new Image().src = base + img;
// caches images, avoiding white flash between background replacements
});

$('.carousel'). on('slide.bs.carousel', function(e) {
$('.animated-bg').css({
backgroundImage: `url(${base}${bgImageArray[e.to]})`
});
});

*,
*::before,
*::after {
margin: 0;
padding: 0;
}
html {
box-sizing: border-box;
}
body {
box-sizing: inherit;
color: #fff !important;
}
.animated-bg {
background-image: url("https://res.cloudinary.com/iolamide/image/upload/v1604569872/home_banner_1_ozdgvm.jpg");
background-size: cover;
background-position: center;
background-repeat: no-repeat;
transition: background 1s;
height: 694px;
position: relative;
display: flex;
flex-direction: column;
align-items: center;
justify-content: center;
}
.animated-bg:before {
content: "";
position: absolute;
top: 0;
bottom: 0;
left: 0;
right: 0;
}
.container {
padding: 3rem;
border-radius: 20px;
width: 700px;
background: rgba(0, 0, 0, 0.3);
display: flex;
flex-direction: column;
align-items: center;
justify-content: center;
text-align: center;
}
.text-top p {
width: 400px;
margin: 30px auto;
text-align: center;
}
h1 {
margin-top: 0;
text-align: center;
font-weight: 600;
}
.carousel-item p {
width: 330px;
text-align: center;
}
.carousel-indicators {
bottom: -50px !important;
}
@media only screen and (max-width: 800px) {
.container {
padding: 2rem;
width: 90%;
}
}
@media only screen and (max-width: 500px) {
.text-top p {
width: 80%;
}
}

<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" rel="stylesheet" />
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js"></script>
<div class="animated-bg" id="animated-bg">
<div class="container">
<div class="text-top" id="texttop">
<h1>Crossfade and Text Carousel</h1>
<p>Fade background image and swipe text at the same time. Also fade the background image to the one that matches the carousel's text when the carousel's indicator is clicked</p>
</div>
<div id="carouselExampleIndicators" class="carousel slide" data-ride="carousel" data-interval="5000">
<ol class="carousel-indicators">
<li data-target="#carouselExampleIndicators" data-slide-to="0" class="active"></li>
<li data-target="#carouselExampleIndicators" data-slide-to="1"></li>
<li data-target="#carouselExampleIndicators" data-slide-to="2"></li>
</ol>
<div class="carousel-inner">
<div class="carousel-item active">
<p>
Carousel Text One
</p>
</div>
<div class="carousel-item">
<p>Carousel Text Two</p>
</div>
<div class="carousel-item">
<p>Carousel Text Three</p>
</div>
</div>
</div>
</div>
</div>

https://jsbin.com/mewiwuv/edit?js，输出