Keeping the edges of an image crisp and defined during a CSS transition can be challenging when adding negative margin. How can you maintain image clarity while applying or removing a filter blur class?
Tested in:
- Firefox 37: Functioning perfectly!
- Chrome 42: Some blurriness observed at the border between the image and parent element
- IE9: Not working as expected
Experience the example yourself: Codepen
HTML:
<link href='http://fonts.googleapis.com/css?family=Montserrat' rel='stylesheet' type='text/css'>
<link href='http://fonts.googleapis.com/css?family=Hind' rel='stylesheet' type='text/css'>
<div class="container">
<img class="blur" src="http://budgetstockphoto.com/bamers/stock_photo_spectrum.jpg"/>
</div>
<div class="col">
<h2 class="montserrat">Hover Over Image</h2>
<hr>
<p class="hind">Preventing an image from having undefined blurry edges can be achieved by adding negative margin, but during a CSS transition this fails. As shown on-hover, the image edges become blurred. How can we ensure image definition during a CSS transition with filter blur?<br><br>Try hovering over the image!</p>
</div>
CSS:
html,body{
margin:0;
text-align:center;
background:#F8F8F8;
height:100%;
}
h2{
margin:1em 0;
padding:0;
line-height:1;
color:#111;
}
p{
margin:1em 0;
padding:0;
line-height:1;
text-align:justify;
color:#999;
}
.montserrat{
font-family: 'Montserrat', sans-serif;
}
.hind{
font-family: 'Hind', sans-serif;
}
hr {
width:100%;
display: block;
height: 1px;
border: 0;
border-top: 1px solid #222;
margin: 1em 0;
padding: 0;
line-height:0;
}
.col{
max-width:400px;
display:inline-block;
height:100%;
float:left;
background:#333;
padding-left:20px;
padding-right:20px;
}
.container{
top: 50%;
left: 50%;
transform: translate(-50%,-50%);
width:10%;
display:inline-block;
padding-top:10%;
position:absolute;
overflow:hidden !important;
border-radius:50%;
-webkit-filter: blur(0px); -moz-filter: blur(0px); -o-filter: blur(0px); -ms-filter: blur(0px); filter: blur(0px);/*prevents image from overflowing*/
}
.container img{
position:absolute;
min-width:calc(100% + 30px);
height:calc(100% + 30px);
left:-15px;
right:-15px;
top:-15px;
bottom:-15px;
-webkit-transition: .5s ease-in-out;
}
.blur{
-webkit-filter: blur(5px); -moz-filter: blur(5px); -o-filter: blur(5px); -ms-filter: blur(5px); filter: blur(5px);
}
A touch of jQuery:
$(document).ready(function(){
$('img').hover(function(){
$(this).toggleClass('blur');
});
});