如何将凹形矩形动画为凸

Question

我使用素描创建了以下形状的矩形。

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当我悬停它，我需要动画和休息如下的形状。

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是否有一种方法，我可以动画它使用css，只有从凹到凸。

任何帮助都将不胜感激。我对svg解决方案也没意见。

下面是svg的小提琴链接。

​

    <svg width="641px" height="313px" viewBox="0 0 641 313" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
    <!-- Generator: Sketch 52.5 (67469) - http://www.bohemiancoding.com/sketch -->
    <title>Concave</title>
    <desc>Created with Sketch.</desc>
    <defs>
        <path d="M0,252.683363 C104.477953,274.894454 210.133596,286 316.966929,286 C423.800262,286 531.811286,274.894454 641,252.683363 L641,565 L0,565 L0,252.683363 Z" id="path-1"></path>
    </defs>
    <g id="Page-1" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd">
        <g id="iteration-3" transform="translate(-752.000000, -3299.000000)">
            <g id="case--study" transform="translate(0.000000, 2766.000000)">
                <g transform="translate(50.000000, 100.000000)" id="case--study--1-copy">
                    <g transform="translate(702.000000, 181.000000)">
                        <use id="bottom" fill="#000000" fill-rule="nonzero" xlink:href="#path-1"></use>
                    </g>
                </g>
            </g>
        </g>
    </g>
</svg>

​

Answer 1

对于CSS唯一的解决方案，我会考虑径向梯度和一些背景动画：

​

.box {
  height:50px;
  width:600px;
  padding-top:50px;
  background:
    /*concave*/
    radial-gradient(410px 50px at 50% 0,transparent, 80%, #000 80.5%) center,
    /*convexe*/
    radial-gradient(410px 50px at 50% 50px,#000, 80%, transparent 80.5%)center,
    linear-gradient(#000,#000) content-box;
  background-size:100% 100%,100% 0px,auto;  
  background-repeat:no-repeat;
  transition:1s all;
}
.box:hover {
  background-size:100% 0,100% 100%,auto;
}

<div class="box"></div>

​

您还可以将其用于全宽度矩形：

​

.box {
  height:50px;
  padding-top:50px;
  background:
    /*concave*/
    radial-gradient(70% 50px at 50% 0,transparent, 80%, #000 80.5%) center,
    /*convexe*/
    radial-gradient(70% 50px at 50% 50px,#000, 80%, transparent 80.5%)center,
    linear-gradient(#000,#000) content-box;
  background-size:100% 100%,100% 0px,auto;  
  background-repeat:no-repeat;
  transition:1s all;
}
.box:hover {
  background-size:100% 0,100% 100%,auto;
}

<div class="box"></div>

​

如果您有更大的高度或动态高度，最好考虑一个伪元素，这样就不会受到高度变化的影响：

​

.box {
  height: 80vh;
  position: relative;
  padding-top: 50px;
  background: #000 content-box;
}

.box::before {
  content: "";
  position: absolute;
  top: 1px;
  left: 0;
  right: 0;
  padding: inherit;
  background: 
   /*concave*/
   radial-gradient(70% 50px at 50% 0, transparent, 80%, #000 80.5%) bottom,      
   /*convexe*/
   radial-gradient(70% 50px at 50% 50px, #000, 80%, transparent 80.5%)bottom;
  background-size: 100% 100%, 100% 0px;
  background-repeat: no-repeat;
  transition: 1s all;
}

.box:hover::before {
  background-size: 100% 0, 100% 100%;
}

<div class="box"></div>

​

更新

您还可以像下面这样调整效果：

​

.box {
  height: 80vh;
  position: relative;
  padding-top: 100px;
  background: #000 content-box;
}


/*concave*/
.box::before {
  content: "";
  position: absolute;
  top: 50px;
  left: 0;
  right: 0;
  height: 51px;
  background: 
   radial-gradient(70% 50px at 50% 0, transparent, 80%, #000 80.5%) top center;
  background-size: 100% 200%;
  background-repeat: no-repeat;
  transition: 0.5s all 0.4s ease-out;
}

/*convexe*/
.box::after {
  content: "";
  position: absolute;
  top: 1px;
  left: 0;
  right: 0;
  height: 51px;
  background:
   radial-gradient(70% 50px at 50% 50px, #000, 80%, transparent 80.5%)bottom center;
  background-size: 200% 0%;
  background-repeat: no-repeat;
  transition: 0.5s all ease-in;
}

.box:hover::before {
  background-position: bottom center;
  background-size: 200% 200%;
  transition: 0.5s all ease-in;
}

.box:hover::after {
  background-size: 100% 100%;
  transition: 0.5s all 0.4s ease-out;
}

<div class="box"></div>

​

Answer 2

一种解决方案可以是使用SVG创建形状，然后通过CSS转换路径：

​

body {
  width: 40vw;
  display: block;
  margin: 0 auto;
}
.path {
    transition: d 2s ease-in-out;
}

.path:hover{     
    d: path('M0 20 Q 50 0 100 20 L100 60 L0 60 Z');
}

<svg viewBox="0 0 100 60" xmlns="http://www.w3.org/2000/svg">
  <path class="path" d="M0 20 Q 50 40 100 20 L100 60 L0 60 Z" fill="black"/>
</svg>
<p>hover over the shape</p>

​