UIKitAppKit

UIKitAppKit is a conceptual cross-platform user interface framework designed to unify the UIKit and AppKit ecosystems. The goal is to provide a single API surface that can power applications on iOS, iPadOS, tvOS, and macOS while preserving the native interaction models and platform conventions of each platform. The project envisions a common set of UI primitives, event handling, and layout paradigms that developers can use across devices without rewriting substantial portions of code.

At its core, UIKitAppKit exposes core UI primitives such as views, view controllers, controls, colors, fonts, and layout constraints. These resemble UIKit types like UIView, UIViewController, UIButton, UIColor, UIFont, and NSLayoutConstraint, but are implemented with adapters that map to AppKit equivalents such as NSView, NSViewController, NSButton, NSColor, NSFont, and NSLayoutConstraint behind the scenes. A central rendering and event pipeline translates touches and pointer events into native events, maps autolayout concepts to the underlying constraint system, and surfaces accessibility through each platform’s accessibility API. The framework aims to support features like appearance customization, trait-like context variations, and responsiveness across different screen sizes.

Architecture is envisioned as layered, including a bridging layer that translates UIKit messages to AppKit calls, a rendering layer that interoperates with each platform’s drawing model, and platform adapters that integrate with macOS windowing, menus, toolbars, and keyboard navigation. While designed to enable code sharing and gradual porting, UIKitAppKit acknowledges platform differences and limitations. Not all AppKit features have direct UIKit equivalents, and macOS-specific UI patterns may require manual adaptations. The concept emphasizes safe interoperability, performance considerations, and a path toward cohesive cross-platform development without abandoning native platform philosophies.