Photo Frame comes with 3 API's that can be extended to add new buttons, effects, and themes. Each API has a very specific purpose, but each are very configurable. Buttons will appear in the toolbar, and can be configured to do anything you need. Custom effects can be created and appear in the effects window alongside the others. And, the themes are a way to customize the display of the Photo Frame field itself. Themes will appear in the dropdown in the fieldtype settings.
Tips for getting started
The best way to get started using the API is to first be sure you download the Button Pack and Effects Pack to get an idea of how the API's can be used. All buttons and effects were created by reusing these API's, so referencing them will be the most comprehensive resource to extending the application. The developer API documentation assumes you understand advanced Object-Oriented Programming patterns with an intimate knowledge of PHP.
Expected Directory Structure
The directory structure is pretty consistent and straightforward. You can create 3 different directories within your photo_frame directory, which is inside your add-on. This tells Photo Frame that your add-on has classes that extend these API's. If the directory structure isn't correct, your classes will not be instantiated.
- system - expressionengine - third_party - your_addon - photo_frame - buttons - effects - themes - themes - third_party - your_addon - photo_frame - buttons - effects - themes