A Library-Agnostic Geometry Editor That Runs Without a UI
Frontend teams that embed drawing tools into dashboards, GIS apps, or canvas editors often hit a wall when the library's UI or map dependency can't be swapped. A Facade-and-adapter architecture makes the editor a drop-in component that survives library migrations and supports imperative, headless use.
Most map-drawing tools bind tightly to a single library and a fixed UI, making integration and customization painful. This design series lays out a library-agnostic geometry editor where the host application interacts only with a Facade, and all rendering passes through a swappable map adapter. Drawers and modifiers use the Strategy pattern, while elements gain hover and edit capabilities through marker interfaces, keeping the core logic free of framework-specific code. Two minimal sequence diagrams show the closed loops for polygon drawing and vertex dragging, with the host never touching the map library directly. The series spans seven articles covering the Facade, event flow, data objects, multi-mode coexistence, auxiliary editing handles, engineering conventions, and the underlying design patterns, each ending with guidance on when to apply or skip a technique.
Separating the editor into a headless, UI-free core and a rendering adapter turns it from a widget into a library — a distinction most map-drawing tools never make.
The design treats the host and the map library as external peers, giving the editor exactly two touchpoints: an imperative API and a coordinate contract. That constraint is what makes cross-library support possible without abstraction leaks.
Ending each article with 'when not to use this' is a rare discipline in technical writing; it signals that the patterns are chosen for specific integration pain, not for architectural purity.