Screen and power

Two modules cover environment awareness: screen (monitors and cursor) and power (battery, idle, suspend, inhibitors).

Screen

import { screen } from '@owear/core'

screen.watch()                                  // connect the native watcher
const displays = await screen.getAllDisplays()  // Display[]
const primary   = await screen.getPrimaryDisplay()
const cursor    = await screen.getCursorScreenPoint()
const nearest   = await screen.getDisplayNearestPoint(cursor)
const matching  = await screen.getDisplayMatching({ x: 0, y: 0, width: 800, height: 600 })

A Display carries geometry, work area, scale, rotation, label, and more:

interface Display {
  id: number          // stable within a session
  primary: boolean
  label: string
  bounds: { x, y, width, height }      // native pixels
  size: { width, height }
  workArea: { x, y, width, height }
  workAreaSize: { width, height }
  scaleFactor: number
  rotation: number
  internal: boolean
  displayFrequency: number
  colorDepth: number
  colorSpace: string
  touchSupport: 'available' | 'unavailable' | 'unknown'
  nativeOrigin: { x, y }
}

Coordinate conversions:

await screen.screenToDipPoint({ x, y })
await screen.dipToScreenPoint({ x, y })

Events

ow.on('screen.added',   ({ display }) => {})
ow.on('screen.removed', ({ display }) => {})
ow.on('screen.changed', ({ display, metrics }) => {})   // metrics: ['bounds'|'workArea'|'scaleFactor'|'rotation']

The SDK also emits these on screen itself (screen.on('added', …)), and auto-connects the watcher on first use.

Power

powerMonitor

import { powerMonitor } from '@owear/core'

await powerMonitor.watch()
await powerMonitor.isOnBatteryPower()      // boolean
powerMonitor.onBatteryPower                // last known value
await powerMonitor.getIdleTime()           // seconds
await powerMonitor.getIdleState(30)        // 'active' | 'idle' | 'locked' | 'unknown'

Events:

powerMonitor.on('suspend', () => {})
powerMonitor.on('resume', () => {})
powerMonitor.on('shutdown', () => {})
powerMonitor.on('lock', () => {})
powerMonitor.on('unlock', () => {})
powerMonitor.on('ac', () => {})        // plugged in
powerMonitor.on('battery', () => {})   // on battery

In the renderer the same events arrive as power.suspend, power.resume, power.ac, power.battery, power.shutdown, power.lock, power.unlock.

powerSaveBlocker

Prevent the system from sleeping while doing long work:

const id = powerSaveBlocker.start('prevent-display-sleep')
// later
powerSaveBlocker.stop(id)
powerSaveBlocker.isStarted(id)

Types: prevent-display-sleep (stronger) and prevent-app-suspension. prevent-display-sleep takes precedence.

Platform backends (Linux)

• suspend/resume/shutdown and lock/unlock: logind D-Bus;
• battery: UPower, with a /sys/class/power_supply fallback;
• idle: X11 MIT-SCREEN-SAVER (libXss, loaded with dlopen); on Wayland idle is reported as unknown/0;
• inhibitors: org.freedesktop.ScreenSaver.

Windows uses PowerBroadcast/WTS/GetLastInputInfo (verify in CI).

Next steps

• screen module reference and power.
• SDK screen and powerMonitor.