Can I create this shape with CSS only? - html

Question

I'm building a hero section for a webpage that has a particular shape, at the moment I'm just using an image as an overlay for the actual section background, but I'm looking to reduce the amount of requests I make and would like to know if the following shape can be done using CSS:
So the black part is where the actual image goes, while the white section is what I'm trying to build using CSS;

Answer 1

Here is an idea with one element and radial-gradient to approximate it
.box {
width: 400px;
height: 200px;
display:inline-block;
overflow:hidden;
position:relative;
}
.box:before,
.box:after{
content:"";
position:absolute;
top:0;
left:0;
right:50%;
bottom:0;
background:
radial-gradient(100% 116.3% at top right, transparent 99%,#fff 100%) top,
radial-gradient(100% 116.3% at bottom left, #fff 99%,transparent 100%) bottom;
background-size:100% 50%;
background-repeat:no-repeat;
}
.box:after {
right:0;
left:50%;
transform:scaleX(-1);
}
body {
background:linear-gradient(to right, purple, blue);
}
<div class="box">
</div>
You can then adjust left/right/bottom properties to control the overal shape by having some oveflow and overlap:
.box {
width: 400px;
height: 200px;
display:inline-block;
overflow:hidden;
position:relative;
}
.box:before,
.box:after{
content:"";
position:absolute;
top:0;
left:-2px;
right:40%;
bottom:-45%;
background:
radial-gradient(100% 116.3% at top right, transparent 99%,#fff 100%) top,
radial-gradient(100% 116.3% at bottom left, #fff 99%,transparent 100%) bottom;
background-size:100% 50%;
background-repeat:no-repeat;
}
.box:after {
right:-2px;
left:40%;
transform:scaleX(-1);
}
body {
background:linear-gradient(to right, purple, blue);
}
<div class="box">
</div>
Here is an idea using SVG to replace the radial-gradient:
.box {
height: 200px;
overflow:hidden;
position:relative;
}
.box:before,
.box:after{
content:"";
position:absolute;
top:0;
left:0;
right:50%;
bottom:0;
background:url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64" preserveAspectRatio="none"><path fill="white" d="M64 64 C56 30 8 48 0 0 L0 64 Z"/></svg>');
background-size:100% 100%;
}
.box:after {
right:0;
left:50%;
transform:scaleX(-1);
}
body {
background:linear-gradient(to right, purple, blue);
}
<div class="box">
</div>
Here is a good online tool to edit the SVG: http://jxnblk.com/paths/. Simply append the path to the url at the end and edit it;
http://jxnblk.com/paths/?d=M64 64 C56 30 8 48 0 0 L0 64 Z