I leave you a rough example so you can get a starting point:
I will use a simple div element, with the width
and height
that the animated image will have, the png sprite as background-image
and background-repeat
set to no-repeat
CSS Needed:
#anim {
width: 14px; height: 14px;
background-image: url(https://ssl.gstatic.com/ui/v1/icons/mail/im/emotisprites/wink2.png);
background-repeat: no-repeat;
}
Markup needed:
<div id="anim"></div>
The trick is basically to scroll the background image sprite up, using the background-position
CSS property.
We need to know the height
of the animated image (to know how much we will scroll up each time) and how many times to scroll (how many frames will have the animation).
JavaScript implementation:
var scrollUp = (function () {
var timerId; // stored timer in case you want to use clearInterval later
return function (height, times, element) {
var i = 0; // a simple counter
timerId = setInterval(function () {
if (i > times) // if the last frame is reached, set counter to zero
i = 0;
element.style.backgroundPosition = "0px -" + i * height + px ; //scroll up
i++;
}, 100); // every 100 milliseconds
};
})();
// start animation:
scrollUp(14, 42, document.getElementById( anim ))
EDIT: You can also set the CSS properties programmatically so you don t have to define any style on your page, and make a constructor function from the above example, that will allow you to show multiple sprite animations simultaneously:
Usage:
var wink = new SpriteAnim({
width: 14,
height: 14,
frames: 42,
sprite: "https://ssl.gstatic.com/ui/v1/icons/mail/im/emotisprites/wink2.png",
elementId : "anim1"
});
var monkey = new SpriteAnim({
width: 18,
height: 14,
frames: 90,
sprite: "https://ssl.gstatic.com/ui/v1/icons/mail/im/emotisprites/monkey1.png",
elementId : "anim4"
});
Implementation:
function SpriteAnim (options) {
var timerId, i = 0,
element = document.getElementById(options.elementId);
element.style.width = options.width + "px";
element.style.height = options.height + "px";
element.style.backgroundRepeat = "no-repeat";
element.style.backgroundImage = "url(" + options.sprite + ")";
timerId = setInterval(function () {
if (i >= options.frames) {
i = 0;
}
element.style.backgroundPosition = "0px -" + i * options.height + "px";
i++;
}, 100);
this.stopAnimation = function () {
clearInterval(timerId);
};
}
Notice that I added a stopAnimation
method, so you can later stop a specified animation just by calling it, for example:
monkey.stopAnimation();
Check the above example here.