Building Responsive UIs with AtCursor: A Step-by-Step Tutorial

// AtCursorProvider (simplified) function AtCursorProvider({ children }) {   const [pos, setPos] = useState({ x: 0, y: 0 });   useEffect(() => {     let raf = null;     function onMove(e) {       const { clientX: x, clientY: y } = e;       if (raf) cancelAnimationFrame(raf);       raf = requestAnimationFrame(() => setPos({ x, y }));     }     window.addEventListener('pointermove', onMove);     return () => window.removeEventListener('pointermove', onMove);   }, []);   return <AtCursorContext.Provider value={pos}>{children}</AtCursorContext.Provider>; } 

Performance considerations

• Throttle or batch updates with requestAnimationFrame.
• Avoid layout-triggering reads (offsetWidth, getBoundingClientRect) on every pointer event.
• Use transform rather than top/left for moving elements.
• Keep the cursor layer simple; heavy DOM or images will slow rendering.

Accessibility

• Ensure cursor-driven features have keyboard and touch equivalents.
• Provide visible focus states and ARIA roles for interactive elements.
• Avoid hiding essential content only accessible via cursor hover — support focus/keyboard navigation.

Cross-platform and native apps

• Electron: reuse web techniques; integrate with native cursor APIs when needed.
• Native (Windows/macOS/Linux): implement similar abstractions using platform event systems (Win32, Cocoa, X11/Wayland).
• Consider high-DPI scaling and pointer precision differences across devices.

Security & privacy

AtCursor implementations that track pointer positions should be careful about privacy-sensitive features (e.g., continuous tracking of user behavior). Only collect and transmit pointer data when necessary and with user consent.

Debugging tips

• Log reduced state snapshots rather than full event objects.
• Visualize hit-testing areas during development.
• Use performance profiling to detect paints and layer recompositions.

Example use cases

• Graphic editors: brush previews, snapping guides.
• Spreadsheets: drag-to-fill previews and live tooltips.
• Maps: coordinate readouts and anchored popovers.
• Gaming UIs: custom crosshairs and ability indicators.
• Complex forms: contextual help that follows the cursor.

Patterns & best practices

• Centralize cursor state in a lightweight manager/provider.
• Expose read-only snapshots to subscribers.
• Let components register interest selectively (e.g., only when visible).
• Provide configuration for offset, delay, and anchor behavior.
• Degrade gracefully on touch or keyboard-only environments.

Conclusion

AtCursor standardizes cursor-aware UI patterns and makes advanced interactions easier, more consistent, and performant. Implement it as a provider/manager, prioritize performance and accessibility, and tailor behavior per-platform for best results.