Photoshop CS6 contains five scripted patterns that can be accessed by right clicking on a path, selecting Fill, or by selecting Fill from the Edit Menu. Once you have the fill dialog box you choose Pattern in the Use selection box, and check the checkbox Scripted Patterns:

Here are examples of patterns generated by scripted Deco pattern fills in Photoshop CS6: Brick Fill (a), Cross Weave (b), Random Fill (c), Spiral (d), and Symmetry Fill (e).

Under the hood

Photoshop CS6 includes five JavaScript files that define five distinct patterns. These patterns are executed by the Deco framework, which is a scriptable environment that is tailored for creating procedural patterns. These five JavaScript files are located in the following directory:

Windows 32 bit:

Program Files (x86)\Adobe\Adobe Photoshop CS6\Presets\Deco

Windows 64 bit:

Program Files\Adobe\Adobe Photoshop CS6 (64 Bit)\Presets\Deco

Mac:

/Applications/Adobe Photoshop CS6/Presets/Deco

It is possible to create new patterns by defining new scripts and placing them into the directories above. The Deco script file acts as a pattern preset and when a new file is added to these directories, the name of the file appears in the Scripted Patterns pull-down menu and the pattern is ready to be used.

Where to get new patterns

There has been a vibrant community of users already at the pre-release forums. A few users created new scripts and some managed to cleverly combine regular Photoshop scripts with Deco scripts to extend the functionality of the feature. For example, Chuck Ubele created a Photoshop script that provides a rich menu of options for the shipped Deco script and one new script (see his website). Others then created beautiful patterns using these new scripts.

For now you can dowload new scripts at the end of this page or from the forum http://forums.adobe.com/community/photoshop/photoshop_scripting.

Once you dowload a script, place it to the directory listed above. The file needs to have the extension jsx. You may have to make the directory writeable to do be able to copy the file there. Depending on your version of Photoshop the new fill (with the same name as your script file) will appear in teh pull down menu for scripted fills either when you open the Fill panel or after you restart Photoshop.

Where to meet other users interested in scripted patterns

The topic related to Deco scripted patterns are discussed in the Photoshop Scripting forum: http://forums.adobe.com/community/photoshop/photoshop_scripting

How to create your own scripted patterns

You can download a documentation on writing your own Deco scripts below. Feel free to contact Radomír Měch or ask other users in the forum. Don’t forget to share your scripts or the resulting patterns! Have fun!

Dowloads

Deco Scripted Patterns

These scripts should be placed to Presets directory, listed above. Please save them with a jsx extension (select Save As in the browser - in the menu or right click on the link, select type All Files and add the .jsx to the file name - Firefox does better job at it than Internet Explorer). New fills will appear in the Fill palette pulldown menu:

Random Fill Boundary.jsx - a modified version of the shipping Random Fill script, in which the pattern is placed only near the edge of a rectangular selection.
Random Fill Boundary Rotate.jsx - a version of the script above, in which the pattern is also rotated when it is placed near the edge.
Random Fill Boundary Rotate Color.jsx - a version of the script above, in which the color of the placed pattern is randomly varied (this was a very succesful script on pre-release forum).

Photoshop Scripts Combined with Deco Scripts

These scripts were created by Richard Y. Kain. They combine a regular photoshop script that defines a user interface and a deco script that then defines the resulting pattern using the input from the regular script.

Varying Path and Spacing.zip - scripts used to place symbols along a path - see the documentation inside the zip file.
PartialPlaneSymmetryFill.zip - these scripts can place pattern along any of the existing symmetries - see the documentation inside the zip file.

Photoshop Script Providing UI for Shipped Scripts

This is a regular Photoshop script that enhance enhance the functionality of scripted patterns. It can be placed anywhere and then it should be executed using File->Scripts->Browse.

Chuck Uebele's Scripted Fill UI - this script creates User Interface, allowing the users to modify various parameters of scripted patterns, without having to edit the files.

Documentation

Programming Deco Scripted Patterns (advanced)
Seek Example.jsx - a script from Section 3.3 of the documentation, illustrating the use of simulation loop. Run it with a square input pattern.