electron/docs/api/screen.md
2016-09-28 18:28:44 +13:00

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# screen
> Retrieve information about screen size, displays, cursor position, etc.
You cannot require or use this module until the `ready` event of the `app`
module is emitted.
`screen` is an [EventEmitter](http://nodejs.org/api/events.html#events_class_events_eventemitter).
**Note:** In the renderer / DevTools, `window.screen` is a reserved DOM
property, so writing `let {screen} = require('electron')` will not work.
An example of creating a window that fills the whole screen:
```javascript
const electron = require('electron')
const {app, BrowserWindow} = electron
let win
app.on('ready', () => {
const {width, height} = electron.screen.getPrimaryDisplay().workAreaSize
win = new BrowserWindow({width, height})
win.loadURL('https://github.com')
})
```
Another example of creating a window in the external display:
```javascript
const electron = require('electron')
const {app, BrowserWindow} = require('electron')
let win
app.on('ready', () => {
let displays = electron.screen.getAllDisplays()
let externalDisplay = displays.find((display) => {
return display.bounds.x !== 0 || display.bounds.y !== 0
})
if (externalDisplay) {
win = new BrowserWindow({
x: externalDisplay.bounds.x + 50,
y: externalDisplay.bounds.y + 50
})
win.loadURL('https://github.com')
}
})
```
## The `Display` object
The `Display` object represents a physical display connected to the system. A
fake `Display` may exist on a headless system, or a `Display` may correspond to
a remote, virtual display.
* `display` object
* `id` Integer - Unique identifier associated with the display.
* `rotation` Integer - Can be 0, 90, 180, 270, represents screen rotation in
clock-wise degrees.
* `scaleFactor` Number - Output device's pixel scale factor.
* `touchSupport` String - Can be `available`, `unavailable`, `unknown`.
* `bounds` Object
* `size` Object
* `workArea` Object
* `workAreaSize` Object
## Events
The `screen` module emits the following events:
### Event: 'display-added'
Returns:
* `event` Event
* `newDisplay` Object
Emitted when `newDisplay` has been added.
### Event: 'display-removed'
Returns:
* `event` Event
* `oldDisplay` Object
Emitted when `oldDisplay` has been removed.
### Event: 'display-metrics-changed'
Returns:
* `event` Event
* `display` Object
* `changedMetrics` String[]
Emitted when one or more metrics change in a `display`. The `changedMetrics` is
an array of strings that describe the changes. Possible changes are `bounds`,
`workArea`, `scaleFactor` and `rotation`.
## Methods
The `screen` module has the following methods:
### `screen.getCursorScreenPoint()`
Returns `Object`:
* `x` Integer
* `y` Integer
The current absolute position of the mouse pointer.
### `screen.getPrimaryDisplay()`
Returns `Display` - The primary display.
### `screen.getAllDisplays()`
Returns `Display[]` - An array of displays that are currently available.
### `screen.getDisplayNearestPoint(point)`
* `point` Object
* `x` Integer
* `y` Integer
Returns `Display` - The display nearest the specified point.
### `screen.getDisplayMatching(rect)`
* `rect` Object
* `x` Integer
* `y` Integer
* `width` Integer
* `height` Integer
Returns `Display` - The display that most closely intersects the provided bounds.