VyUI alpha
Composables

getViewportSize

Source
The LynxView's size in logical px, converted from SystemInfo's physical pixels.

Overview

Lynx has no window.innerWidth; the background thread exposes physical pixels via SystemInfo.pixelWidth / pixelHeight plus pixelRatio. getViewportSize does the division:

import { getViewportSize } from '@vyui/core'

const size = getViewportSize() // { width: 390, height: 844 } — or null

Returns null off-Lynx (web / vitest) or before SystemInfo resolves, so callers pick their own fallback:

const height = getViewportSize()?.height ?? 800

This is what VySheet and VyScrollView use internally for their viewport estimates.

Not reactive

SystemInfo is a static snapshot — it doesn't update on rotation or split screen. Re-read it when layout actually changes: VyApp emits viewport-change from the root layoutchange event for exactly this.

Main-thread worklets can't call this (cross-file worklet calls don't resolve on Lynx); read SystemInfo inline in the worklet instead.

Signature

getViewportSize(): ViewportSize | null — { width: number, height: number } in logical px.

Related

useGlobalEvent

Subscribe to a Lynx GlobalEventEmitter event — native-to-JS signals from the host app — with automatic cleanup.

useAppConfig

Inject the merged AppConfig provided by the VyUI plugin.