CSS动画：宽度从右到左，高度从底部到顶部

Question

我正在尝试解决一个问题，即如何让div的宽度从右到左扩展，使得不同容器的高度从底部到顶部延伸。我正在尝试创建一个CSS动画，它将在正方形中旋转，并模拟边框。这里是链接到我的CodePen https://codepen.io/Archezi/pen/xReqvq?editors=0100 如果有帮助的话。

这里是我的HTML代码，.container 是主要的包装器，.circle 是一个动画线条，line1-line4是我正在尝试动画化的正方形的边框。

<div class="container">
    <div class="circle "></div>
    <div class="line1  "></div>
    <div class="line2  "></div>
    <div class="line3  "></div>
    <div class="line4  "></div>
</div>

这是我的CSS样式表。

body {
    margin: 0 auto;
}
.container {
    position:relative;
    margin: 50px auto;
    width: 800px;
    height:800px;
    border:1px solid #000;
}
.circle {
    display:inline-block;
    width: 25px;
    height: 25px;
    border-radius:50%;
    position: absolute;
    top:100px;
    left:100px;
    background:#000;
    animation: myframes 4s ease-in-out 0s infinite;

    /* animation-name: myanimation;
    animation-duration:5s;
    animation-timing-function:ease-in-out;
    animation-delay: 0s;
    animaiton-iteration-count: infinite;
    animation-direction: normal;
    animation-fill-mode: forwards;
    animation-play-state: running; */
}
.line1 {
    height:15px;
    width:15px;
    position:absolute;
    top:105px;
    left:105px;
    background:red;
    animation: squerframe 2s ease-in-out 0s infinite;
}
.line2 {
    height:15px;
    width:15px;
    position:absolute;
    top:105px;
    left:205px;
    background:green;
    animation: squerframe2 2s ease-in-out 1s infinite;
}
.line3 {
    height:15px;
    width:15px;
    position:absolute;
    top:205px;
    left:205px;
    background-color:red;
    animation: squerframe3 2s ease-in-out 2s infinite;
}

.line4 {
    height:15px;
    width:15px;
    position:absolute;
    top:205px;
    left:105px;
    background:green;
    animation: squerframe4 2s ease-in-out 3s infinite;
}
@Keyframes squerframe 
{
    0%  {  width:15px; opacity: 1; }
    50% {  width:115px; }
    100%{  width:115px; opacity: 0; }
}
@Keyframes squerframe2 
{
    0%  { height:15px;  opacity: 1; }
    50% { height:115px;             }
    100%{ height:115px;  opacity: 0;  }
}
@Keyframes squerframe3 
{
    0%  { width:115px; opacity: 0;}
    50% { width:115px; }
    100%{ width:15px; opacity: 1; }
}
@Keyframes squerframe3 
{
    0%  { width:15px; opacity: 1;}
    50% { width:115px;  }
    100%{ width:115px; opacity: 0; }
}
@Keyframes squerframe4 
{
    0%  {  height:15px; opacity: 1;}
    50% {  height:115px;  }
    100%{  height:115px; opacity: 0; }
}

@keyframes myframes 
{
    0%   { top:100px; left:100px; }
    25%  { top:100px; left:200px; }
    50%  { top:200px; left:200px; }  
    75%  { top:200px; left:100px; }
    100% { top:100px; left:100px; }
}

请引导我找到解决方案，或者指引我采用不同的方法解决这个问题。谢谢！

- Archezi

---

抱歉，我不明白问题出在哪里。CodePen 不起作用吗？你为什么需要另一个解决方案？ - vals

Answer 1

这里的问题是，你需要让第三行具有绝对右侧，这样当宽度改变时，它会向左拉伸。

另外，第四行应该有一个绝对底部，这样它就能向上拉伸。

我建议你添加一个容器或更改当前div.container的尺寸（如我在示例中所做），将这四行用作该容器的极限。

以下是已经修改过的示例，可供参考：

https://codepen.io/anon/pen/MbRvGM?editors=0100

body {
  margin: 0 auto;
}
.container {
  position:relative;
  margin: 50px auto;
  width: 115px;
  height:115px;
  border:1px solid #000;
}
.circle {
  display:inline-block;
  width: 25px;
  height: 25px;
  border-radius:50%;
  position: absolute;
  top:0px;
  left:0px;
  background:#000;
  animation: myframes 4s ease-in-out 0s infinite;

/*   animation-name: myanimation;
  animation-duration:5s;
  animation-timing-function:ease-in-out;
  animation-delay: 0s;
  animaiton-iteration-count: infinite;
  animation-direction: normal;
  animation-fill-mode: forwards;
  animation-play-state: running; */



}
.line1 {
  height:15px;
  width:15px;
  position:absolute;
  top:0px;
  left:0px;
  background:red;
  animation: squerframe 2s ease-in-out 0s infinite;
}
.line2 {
  height:15px;
  width:15px;
  position:absolute;
  top:0px;
  left:100px;
  background:green;
  animation: squerframe2 2s ease-in-out 1s infinite;
}
.line3 {
  height:15px;
  width:15px;
  position:absolute;
  top:100px;
  right:0px;
  float: right;
  background-color:red;
  animation: squerframe3 2s ease-in-out 2s infinite;
}

.line4 {
  height:15px;
  width:15px;
  position:absolute;  
  left:0px;
  bottom: 0;
  background:green;
  animation: squerframe4 2s ease-in-out 3s infinite;
}
@Keyframes squerframe 
{
  0%  {  width:15px; opacity: 1; }
  50% {  width:115px; }
  100%{  width:115px; opacity: 0; }
}
@Keyframes squerframe2 
{
  0%  { height:15px;  opacity: 1; }
  50% { height:115px;             }
  100%{ height:115px;  opacity: 0;  }
}
@Keyframes squerframe3 
{
  0%  { width:115px; opacity: 0;}
  50% { width:115px; }
  100%{ width:15px; opacity: 1; }
 }
@Keyframes squerframe3 
{
  0%  { width:15px; opacity: 1;}
  50% { width:115px;  }
  100%{ width:115px; opacity: 0; }
}
@Keyframes squerframe4 
{
  0%  {  height:15px; opacity: 1;}
  50% {  height:115px;  }
  100%{  height:115px; opacity: 0; }
}

 @keyframes myframes 
{
   0%   { top:0px; left:0px; }
   25%  { top:0px; left:100px; }
   50%  { top:100px; left:100px; }  
   75%  { top:100px; left:0px; }
   100% { top:0px; left:0px; }
}

- Rares Hideg

---

谢谢你提供的解决方案。我之前也在考虑这个问题，但我想知道是否有其他解决方案。感谢你的帮助，我会尝试去调试一下。 - Archezi

Answer 2

添加额外的样式

animation: squerframe4 2s ease-in-out 3s infinite;
-webkit-animation: squerframe4 2s ease-in-out 3s infinite;
-moz-animation: squerframe4 2s ease-in-out 3s infinite;

并且用于关键帧

@Keyframes squerframe...
@-webkit-Keyframes squerframe...
@-moz-Keyframes squerframe...

- aavrug