Running without arguments will show usage: python sprite.py

The usage is as follows: python sprite.py [url pattern]

Example: python sprite.py icons/sets resources/images "static_url('images/{set}/{image}')"

Running Provided Example (from this folder, containing sprite.py): python sprite.py example-sets example-output

Note: The url pattern is optional, and defaults to the url pattern in the above example.

Spriter WILL overwrite files it sees. You only have to worry about this if you have: /(a set name)/images.css /(a set name)/sprites.png /(a set name)/(name of an unspritable image)

So, not much danger... but there is a danger.

The script is written in Python. It requires:

• Either: Python 2.6+ or Python 2.5 with simplejson installed
• PIL (Python Imaging Library)

• Takes a “sets” folder, which should have sub-folder “sets” of icons to be sprited.
• Takes an output folder, under which it will create new set folders containing CSS and image files.
• Combines images under a maximum size (128x128 by default—see Configuration) into a sprites.png file in the output set folder.
• Creates CSS referencing these images using a URL template (SproutCore oriented by default—see URLs)

You may often have more than one set of icons. For instance, you could have a main set and an alternate set that you only want to load on demand, and still want that additional set to be sprited.

Alternatively, you may have images meant for repeating backgrounds, but which should still be sprited.

To facilitate this, the spriting script takes, as its first argument, the location of a sets folder. You put your sets as subfolders into this folder. For instance, this could be your layout:

my-sets
	common
		delete-32.png
		delete-64.png
		file-32.png
		file-64.png
		upload.png
	repeat-x
		config.js       — see Configuration
		toolbar.png
		footer.png
		header.png
	odd-feature
		some-icon.png
		other-icon.png

The CSS has to reference the images. Only problem: it doesn’t know where those images are.

Usually, you’d just be able to use paths relative to the stylesheet. However, if you are using SproutCore, this won’t work because it moves around all the CSS and JavaScript.

Without SproutCore, you'd need: url('sprites.png') With SproutCore, you need something more like: static_url(‘images/set/sprites.png’)

By default, the script structures it for SproutCore, just like above. It uses a URL template of "static_url('images/{set}/{image}')". You can easily change this by changing the third argument for the script.

There are a few things that are configurable. Configuration is done per-set.

Configuration files are JSON files, and are very simple. They are optional, and take at most five parameters:

• prepend-set-name: default: True. Determines whether to prepend the set name onto the CSS class. If false, the CSS class will simply be the name of the image (not including extension).

• max-size: default: 128. The maximum size for sprited images. Images above this size will be put as separate images. Useful if you have some really high-res icons you don’t want to sprite, but want to keep with the set.

• repeat: Default: “none”; can also be “x” or “y”. Determines the repeat mode. If repeat is “x,” the sprites will be laid out in rows; if “y,” the sprites will be laid out in columns. The generated CSS will include repeat-x or repeat-y, respectively.

Note that all images in a repeat-x set must be the same width, and all images in a repeat-y set must be the same height. The width or height of these images should be set using repeat-width and repeat height, which are discussed below.


• repeat-width: Default: 32. If repeat=“x,” the width of the repeat images. If your repetition does not require a pattern, you could set this to 1.


• repeat-height: See that lovely summary of repeat-width above? Well, this is the same, but for y/height.

Where do the config files go? In the set folder, named config.json.

Nice and simple, eh?