使用伪元素（及其高度）的视差

Question

我正在尝试在我的网站上创建视差效果，并研究了几种 css 解决方案。我选择了一个可以看到的 Joshua Bemenderfer here

我稍微编辑了示例代码以使问题更加明显，但是因为它使用的是伪元素，与其父元素的大小相匹配，所以当我调整视差部分大小时我很难停止白色 space 在图像移动时不可见。

（注意，您必须在代码段上全屏查看问题）：

*编辑：Codepen because the snippet isn't showing the problem in full screen or in the preview

/* Tiny reset thingy */
body,html{margin:0;padding:0;}

.wrapper {
  /* The height needs to be set to a fixed value for the effect to work.
   * 100vh is the full height of the viewport. */
  height: 100vh;
  /* The scaling of the images would add a horizontal scrollbar, so disable x overflow. */
  overflow-x: hidden;
  /* Enable scrolling on the page. */
  overflow-y: auto;
  /* Set the perspective to 2px. This is essentailly the simulated distance from the viewport to transformed objects.*/
  perspective: 2px;
}

.section {
  /* Needed for children to be absolutely positioned relative to the parent. */
  position: relative;
  /* The height of the container. Must be set, but it doesn't really matter what the value is. */
  height: 200px;
  
  /* For text formatting. */
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  text-shadow: 0 0 5px #000;
}

.parallax::after {
  /* Display and position the pseudo-element */
  content: " ";
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  
  /* Move the pseudo-element back away from the camera,
   * then scale it back up to fill the viewport.
   * Because the pseudo-element is further away, it appears to move more slowly, like in real life. */
  transform: translateZ(-1px) scale(1.5);
  /* Force the background image to fill the whole element. */
  background-size: 100%;
  /* Keep the image from overlapping sibling elements. */ 
  z-index: -1;
}

/* The styling for the static div. */
.static {
  background: red;
}

/* Sets the actual background images to adorable kitties. This part is crucial. */
.bg1::after {
  background-image: url('https://placekitten.com/g/900/700');
}

.bg2::after {
  background-image: url('https://placekitten.com/g/800/600');
}

<main class="wrapper">
  <section class="section static">
    <h1>Boring</h1>
  </section>
  <section class="section parallax bg2">
    <h1>SO FWUFFY AWWW</hi>
  </section>
    <section class="section static">
    <h1>Boring</h1>
  </section>
</main>

关于如何解决这个问题有什么想法吗？我似乎无法在不破坏效果的情况下让它工作

谢谢

Answer 1

使伪元素变大以隐藏这种不良效果。只需将顶部底部值设置为负数即可：

/* Tiny reset thingy */
body,html{margin:0;padding:0;}

.wrapper {
  height: 100vh;
  overflow-x: hidden;
  overflow-y: auto;
  perspective: 2px;
}

.section {
  position: relative;
  height: 200px;
  
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  text-shadow: 0 0 5px #000;
}

.parallax::after {
  content: " ";
  position: absolute;
  top: -100px;
  right: 0;
  bottom: -100px;
  left: 0;
  
  transform: translateZ(-1px) scale(1.5);
  background-size: 100% auto;
  z-index: -1;
}

/* The styling for the static div. */
.static {
  background: red;
}

/* Sets the actual background images to adorable kitties. This part is crucial. */
.bg1::after {
  background-image: url('https://placekitten.com/g/900/700');
}

.bg2::after {
  background-image: url('https://placekitten.com/g/800/600');
}

<main class="wrapper">
  <section class="section static">
    <h1>Boring</h1>
  </section>
  <section class="section parallax bg2">
    <h1>SO FWUFFY AWWW</h1>
  </section>
    <section class="section static">
    <h1>Boring</h1>
  </section>
</main>

使用伪元素（及其高度）的视差

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