Updated version of article published on September 27, 2012. Updates include latest data on current browser support, removing unnecessary vendor prefixes from code samples, and addition of live demo on CodePen.
Scaling, skewing and rotating any element is possible with the CSS3
transform property. It’s supported in all modern browsers without vendor prefixes. If you need to support Blackberry Browser and UC Browser for Android, you’ll need to use the
-webkit- prefix, e.g.
Great stuff. However, this rotates the whole element — its content, border and background image. What if you only want to rotate the background image? Or what if you want the background to remain fixed while the element is rotated?
Currently, there’s no W3C proposal for background-image transformations. It would be incredibly useful so I suspect one will appear eventually, but that doesn’t help developers who want to use similar effects today.
Fortunately, there is a solution. In essence, it’s a hack which applies the background image to a before or after pseudo element rather than the parent container. The pseudo element can then be transformed independently.
Transforming the Background Only
The container element can have any styles applied but it must be set to
position: relative since our pseudo element will be positioned within it. You should also set
overflow: hidden unless you’re happy for the background to spill out beyond the container.
We can now create an absolutely-positioned pseudo element with a transformed background. The z-index is set to -1 to ensure it appears below the container’s content.
background: url(background.png) 0 0 repeat;
Note you may need to adjust the pseudo element’s width, height and position. For example, if you’re using a repeated image, a rotated area must be larger than its container to fully cover the background:
Fixing the Background on a Transformed Element
Continue reading %How to Apply CSS3 Transforms to Background Images%