Widget System

PaperCast features a modular widget system. Widgets are predefined Node structures that users can drag and drop into the visual builder.

Basic vs Advanced Nodes

In src/registry/categories/, widgets are grouped into categories:

1. Basic Nodes: Core primitives like text, image, and divider. These are usually atomic (they do not split across pages).
2. Layout Nodes: Containers like row, column, and stack. These nodes often implement custom split functions to allow their children to paginate seamlessly.
3. Advanced Nodes: Complex components like table or rich text components.

Drag and Drop

The visual builder uses a DnD system to allow users to pull from the widget registry and drop them into the document.

When a widget is dropped:

1. The builder reads the default JSON schema defined for that widget (e.g., a basic Text widget drops with { type: "text", content: "New Text" }).
2. The astManipulators inject this new node into the active AST.
3. The store updates, triggering a re-render and re-pagination.