Install

$ pip install pysprites

Example

$ pysprites -i page1.psd -m icon- -b -r -c page1.css -o page1.png

This command will import layers whose name starts with icon-, from page1.psd, reposition them, output the css for each sprite to page1.css, and output the merged png to page1.png

Command line

$ pysprites [args...]

-i a.psd b.psd ... : import psd layer from psd files (need psd_tools)
-a x.png y.png ... : add png files
-m filter  : only handle layer or image name startswith filter
-p padding : add padding for each sprite
-r         : reposition sprites
-cp string : use string as css class prefix
-b         : gen sprite width and height for css
-c out.css : output css to file
-o out.png : output merged png to file

Framework

Actually, everything is in a single file : pysprites/sprites.py.

In a task, everything present as a “General Sprite Process Group” (gsp), it is struct is as follow:

gsp :: (width, height, img, padding, prefix, args)
img :: list of [[name, [width, height],[left, top], PIL_object]

And the gsp go though handlers, a handler reposition the img, and a handler save it to png, and so on.

Reposition Algorithm

1. Select two most height sprites and the final image height.

2. Find a lowest gap.

3. Select a longest sprite that can be insert to left, and insert it.

4. If cannot insert it, fill the gap and goto step2.

5. Repeat untail every sprite has been inserted.

Using a EdgeLines struct to maintain the lowest gap, and the gsp_reposition function implements this algorithm. See the code in pysprites/sprites.py

Contribute

I think this tools is good enough for me. However, Welcome for new handlers, for example, import the layer from a GIMP xcf file, or new reposition algorithm, or any participation !

Enjoy it!