Let's start with something easy: I'm sure that at some point you will either have used or created image sprites, right? If you're a SASS developer, no doubt you will have availed yourself of the sprite mixins from Compass, and used an app such as Koala to compile, or compiled directly from the command line.
Note
A copy of the relevant files for creating sprites using Compass can be found in the code download that accompanies this book, in the Tutorial21A
folder.
The process is relatively straightforward, but you still have to set up a Compass
project, install a GUI application (if you're using one), and so on, which is a real pain! We could use an online application such as SpritePad (http://spritepad.wearekiss.com/) instead, but again that's a manual process, and it's prone to error. Instead, we can easily use PostCSS to help us here —over and above the normal variables that we declare at the top of any gulp file, there is very little required in order to produce basic...