如何在缩放动画中保持原点在图像的中心？

Question

我有一个类似于这个小提琴的情况,我有一个CSS3动画,可以缩放绝对位于另一个元素中心的元素.然而,当动画发生时,它是偏心的,如示例中相对于蓝色的红色方块所示.我该如何居中？我在该transform-origin属性周围尝试了几种配置,但这并没有产生正确的结果.

代码如下:

@-webkit-keyframes ripple_large {
  0% {-webkit-transform:scale(1);}
  75% {-webkit-transform:scale(3); opacity:0.4;}
  100% {-webkit-transform:scale(4); opacity:0;}
}

@keyframes ripple_large {
  0% {transform:scale(1); }
  75% {transform:scale(3); opacity:0.4;}
  100% {transform:scale(4); opacity:0;}
}

.container {
  position: relative;
  display: inline-block;
  margin: 10vmax;
}

.cat {
  height: 20vmax;
}

.center-point {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  height: 10px;
  width: 10px;
  background: blue;
}

.to-animate {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  border: 1px solid red;
  height: 5vmax;
  width: 5vmax;
  transform-origin:center;
}

.one {
  -webkit-animation: ripple_large 2s linear 0s infinite;
  animation: ripple_large 2s linear 0s infinite;
}

.two {
  -webkit-animation: ripple_large 2s linear 1s infinite;
  animation: ripple_large 2s linear 1s infinite;
}

Answer 1

问题在于你正在消除translate转型.

当您指定新转换(动画内部的转换)时,它会覆盖第一个转换,因此您需要将它们添加到同一transform属性中.在您的情况下,您将删除修复中心对齐的翻译:

@keyframes ripple_large {
  0% {
    transform: translate(-50%, -50%) scale(1) ;
  }
  75% {
    transform: translate(-50%, -50%) scale(3) ;
    opacity: 0.4;
  }
  100% {
    transform:translate(-50%, -50%)  scale(4) ;
    opacity: 0;
  }
}

.container {
  position: relative;
  display: inline-block;
  margin: 10vmax;
}

.cat {
  height: 20vmax;
}

.center-point {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  height: 10px;
  width: 10px;
  background: blue;
  transform-origin:center;
}

.to-animate {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  border: 1px solid red;
  height: 5vmax;
  width: 5vmax;
}

.one {
  -webkit-animation: ripple_large 2s linear 0s infinite;
  animation: ripple_large 2s linear 0s infinite;
}

.two {
  -webkit-animation: ripple_large 2s linear 1s infinite;
  animation: ripple_large 2s linear 1s infinite;
}

<div class='container'>
  <img src='http://www.catster.com/wp-content/uploads/2017/08/Pixiebob-cat.jpg' class='cat'>
  <div class='center-point'>
  </div>
  <div class='to-animate one'></div>
  <div class='to-animate two'></div>
</div>

UPDATE

如评论所述,最好使用除翻译之外的其他方法来居中您的元素以避免更改动画,因为这可以与其他元素一起使用.