Rotating a background image with CSS3 - css

Question

I have a background image that has an arrow that points to the right. When a user clicks on the button, the selected state changes the arrow to point down (using a different background position in my image sprite).
Is there anyway to animate this using CSS3 so once the button is clicked and jQuery assigns it a "selected" class, it will rotate in an animation (only 90 degrees) from the right to down? (preferably using the single image/position with the arrow that points to the right)
I'm unsure as to whether transform or key animation frames need to be used.

Answer 1

you could use the ::after (or ::before) pseudo-element, to generate the animation
div /*some irrelevant css */
{
background:-webkit-linear-gradient(top,orange,orangered);
background:-moz-linear-gradient(top,orange,orangered);
float:left;padding:10px 20px;color:white;text-shadow:0 1px black;
font-size:20px;font-family:sans-serif;border:1px orangered solid;
border-radius:5px;cursor:pointer;
}
/* element to animate */
div::after /* you will use for example "a::after" */
{
content:' ►'; /* instead of content you could use a bgimage here */
float:right;
margin:0 0 0 10px;
-moz-transition:0.5s all;
-webkit-transition:0.5s all;
}
/* actual animation */
div:hover::after /* you will use for example "a.selected::after" */
{
-moz-transform:rotate(90deg);
-webkit-transform:rotate(90deg);
}
HTML:
<div>Test button</div>
in your case you will use element.selected class instead of
jsfiddle demo: http://jsfiddle.net/p8kkf/
hope this helps

Answer 2

Here is a rotating css class that I have used to spin a background image:
.rotating {
-webkit-animation: rotating-function 1.25s linear infinite;
-moz-animation: rotating-function 1.25s linear infinite;
-ms-animation: rotating-function 1.25s linear infinite;
-o-animation: rotating-function 1.25s linear infinite;
animation: rotating-function 1.25s linear infinite;
}
#-webkit-keyframes rotating-function {
from {
-webkit-transform: rotate(0deg);
}
to {
-webkit-transform: rotate(360deg);
}
}
#-moz-keyframes rotating-function {
from {
-moz-transform: rotate(0deg);
}
to {
-moz-transform: rotate(360deg);
}
}
#-ms-keyframes rotating-function {
from {
-ms-transform: rotate(0deg);
}
to {
-ms-transform: rotate(360deg);
}
}
#-o-keyframes rotating-function {
from {
-o-transform: rotate(0deg);
}
to {
-o-transform: rotate(360deg);
}
}
#keyframes rotating-function {
from {
transform: rotate(0deg);
}
to {
transform: rotate(360deg);
}
}