Fill element with slanted background on hover - css

Question

I'm trying to create an CSS button hover effect. But I didn't manage to fill the element with a slanted shape.
How the hover effect was planned:
Screenshot 1: How it looks actually.
Screenshot 2: How I want the hover effect to look like with slanted side.
.button_sliding_bg {
color: #31302B;
background: #FFF;
padding: 12px 17px;
margin: 25px;
font-family: 'OpenSansBold', sans-serif;
border: 3px solid #31302B;
font-size: 14px;
font-weight: bold;
letter-spacing: 1px;
text-transform: uppercase;
border-radius: 2px;
display: inline-block;
text-align: center;
cursor: pointer;
box-shadow: inset 0 0 0 0 #31302B;
-webkit-transition: all ease 0.8s;
-moz-transition: all ease 0.8s;
transition: all ease 0.8s;
}
.button_sliding_bg:hover {
box-shadow: inset 200px 0 0 0 #31302B;
color: #FFF;
}
<button class="button_sliding_bg">Buttontext</button>

Answer 1

You can use the technique described in this answer : Fill element from center on hover and skew the pseudo element so it fills the button with a slant :
div {
position: relative;
display: inline-block;
padding: 15px 70px;
border: 5px solid #B17461;
color: #B17461;
font-size: 30px;
font-family: arial;
transition: color .5s;
overflow:hidden;
}
div:before {
content: '';
position: absolute;
top: 0; left: 0;
width: 130%; height: 100%;
background: #B17461;
z-index: -1;
transform-origin:0 0 ;
transform:translateX(-100%) skewX(-45deg);
transition: transform .5s;
}
div:hover {
color: #fff;
}
div:hover:before {
transform: translateX(0) skewX(-45deg);
}
<div>BUTTON</div>
Don't forget to add vendor prefixes for browser support (see canIuse for more info).

Answer 2

I believe that you are actually looking for the end state to fill the entire element with background color and not leave the gap. You could also do it with linear-gradient background images and transition their background-size and background-position like in the below snippet.
One disadvantage of using linear-gradient over pseudo-elements or transforms is that the browser support is lower but it doesn't need extra pseudo-elements and so can leave them spare for other use.
.button_sliding_bg {
color: #31302B;
background: #FFF;
padding: 12px 17px;
margin: 25px;
font-family: 'OpenSansBold', sans-serif;
border: 3px solid #31302B;
font-size: 14px;
font-weight: bold;
letter-spacing: 1px;
text-transform: uppercase;
border-radius: 2px;
display: inline-block;
text-align: center;
cursor: pointer;
background-image: linear-gradient(135deg, #31302B 50%, transparent 51%);
background-size: 100px 100px; /* some initial size to get the slanted appearance */
background-position: -50px -50px; /* negative positioning to hide it initially */
background-repeat: no-repeat;
transition: all ease 0.8s;
}
.button_sliding_bg:hover {
background-size: 200% 200%; /* 200% because gradient is colored only for 50% */
background-position: 0px 0px; /* bring it fully into view */
color: #FFF;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/prefixfree/1.0.7/prefixfree.min.js"></script>
<button class="button_sliding_bg">Buttontext</button>
<button class="button_sliding_bg">Button text lengthy</button>
<button class="button_sliding_bg">Button text <br> with line break</button>
<button class="button_sliding_bg">Button text <br> with <br> multiple <br> line <br>breaks</button>

Answer 3

You can use css :after.
Jsfiddle
.button_sliding_bg {
color: #31302B;
background: #FFF;
padding: 12px 17px;
margin: 25px;
font-family:'OpenSansBold', sans-serif;
border: 3px solid #31302B;
font-size: 14px;
font-weight: bold;
letter-spacing: 1px;
text-transform: uppercase;
border-radius: 2px;
display: inline-block;
text-align: center;
cursor: pointer;
box-shadow: inset 0 0 0 0 #31302B;
-webkit-transition: all ease 0.8s;
-moz-transition: all ease 0.8s;
transition: all ease 0.8s;
position: relative;
}
.button_sliding_bg:hover {
box-shadow: inset 200px 0 0 0 #31302B;
color: #FFF;
}
.button_sliding_bg:after {
content:'';
display: block;
position: absolute;
right: 0;
bottom: 0;
width: 0;
height: 0;
border-width: 0 0 0 0;
border-color: transparent transparent #fff transparent;
border-style: solid;
border-width: 0 0 32px 30px;
-webkit-transition: all ease 0.8s;
-moz-transition: all ease 0.8s;
transition: all ease 0.8s;
}
<button class="button_sliding_bg">Buttontext</button>