我如何动画::元素从右到左的元素宽度之后

Question

我有一个按钮，该按钮使用:: pseudo填充背景。目前，它从左到右填充，这是有意义的，因为宽度从0到100％。但是，我希望它以填充方式翻转。

a.project--link {
  margin: 2rem auto 0 auto;
  padding: 1rem 0;
  display: block;
  border: 1px solid black;
  box-shadow: 0 0 10px rgba(red, .2);
  width: 100%;
  transition: all .2s ease;
  z-index: 1;
  }
  a.project--link:hover {
    box-shadow: 0 0 10px rgba(red, .7);
    transform: scale(1.02);
    transition: all .2s ease;
  }
  a.project--link::after {
    display: block;
    content: '';
    height: 100%;
    width: 0;
    top: 0;
    z-index: -1;
    background-color: red;
    position: absolute;
  }
a.project--link:hover::after {
  width: 100%;
  transition: .3s linear;
}

<a href="#" class="project--link">View Project</a>

如果有人能阐明如何翻转动画，那将是一个巨大的帮助。

Answer 1

使用transform: scaleX()代替width并使用transform-origin控制方向。

a.project--link {
  margin: 2rem auto 0 auto;
  padding: 1rem 0;
  display: block;
  border: 1px solid black;
  box-shadow: 0 0 10px rgba(red, .2);
  width: 100%;
  transition: all .2s ease;
  z-index: 1;
  position: relative;
}
a.project--link:hover {
  box-shadow: 0 0 10px rgba(red, .7);
  transform: scale(1.02);
  transition: all .2s ease;
  transform-origin: 0 100%;
}
a.project--link::after {
  display: block;
  content: '';
  height: 100%;
  top: 0;
  width: 100%;
  z-index: -1;
  background-color: red;
  position: absolute;
  transition: .3s linear;
  transform: scaleX(0);
  transform-origin: 100% 0;
}
a.project--link:hover::after {
  transform: scaleX(1);
}

<a href="#" class="project--link">View Project</a>