CocoaAppKit

CocoaAppKit is an open-source GUI framework intended to provide a Cocoa-inspired API for building desktop applications. It draws on concepts from Apple's Cocoa AppKit while aiming to be portable across platforms. The project states that it is not affiliated with Apple.

Core features include a hierarchically organized object model with a responder chain, target-action for user events, a view-based layout system, and support for constraints-based autolayout. Windows, views, and controls map roughly to NSWindow, NSView, and common widgets in AppKit, allowing developers familiar with Cocoa patterns to work with CocoaAppKit.

Architecture comprises a core UI layer, a rendering backend, and platform adapters. The core library defines primitives such as windows, views, and events; backends handle actual rendering using native widgets or custom drawing; and platform adapters translate system calls to the framework's API. Accessibility and printing services are included.

Language bindings typically provide C++ interfaces, with optional wrappers for other languages such as Swift or Python. CocoaAppKit is used in educational contexts and by developers experimenting with Cocoa-style interfaces on non-Apple platforms, or by those seeking a familiar API surface for cross-platform GUI development.

See also: AppKit, Cocoa, GUI framework, cross-platform UI toolkit.