by Jens Alfke ⟿ December 20, 2007

Santa has an early Xmas present for all you good Leopard programmers: GeekGameBoard, a new piece of sample code by the anonymous engineer elves at Apple.

[Update: GeekGameBoard is now an open-source project hosted at

GeekGameBoard is an example of using Core Animation to present the user interface of a board or card game. It implements a small framework for implementing such games, with domain-specific classes like “Grid” and “Piece”, and examples of several game definitions built on top of the framework.
Some of the generally-useful Core Animation techniques illustrated are:
• Hit testing
• Dragging CALayers with the mouse
• Loading images from files and setting them as layer contents
• 3D “card-flip” animations

Framework classes include Bit, Piece, PlayingCard, HexGrid and more. It comes with sample games from Klondike solitaire to Checkers and even Tic-Tac-Toe. It’s all ready for you to add AI, network play, new game definitions…

PS: Icon websites like IconFactory, InterfaceLift and DeviantArt are great places to get artwork for game pieces. (My personal favorite game pieces are Ginko’s Icons, shown on the right.) Just be aware that most icons, even if freeware, require you to get the copyright holder’s permission for anything other than personal use.