electron/docs/api/system-preferences.md
2016-12-21 19:21:04 -08:00

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# systemPreferences
> Get system preferences.
Process: [Main](../glossary.md#main-process)
```javascript
const {systemPreferences} = require('electron')
console.log(systemPreferences.isDarkMode())
```
## Events
The `systemPreferences` object emits the following events:
### Event: 'accent-color-changed' _Windows_
Returns:
* `event` Event
* `newColor` String - The new RGBA color the user assigned to be their system
accent color.
### Event: 'color-changed' _Windows_
Returns:
* `event` Event
### Event: 'inverted-color-scheme-changed' _Windows_
Returns:
* `event` Event
* `invertedColorScheme` Boolean - `true` if an inverted color scheme, such as
a high contrast theme, is being used, `false` otherwise.
## Methods
### `systemPreferences.isDarkMode()` _macOS_
Returns `Boolean` - Whether the system is in Dark Mode.
### `systemPreferences.isSwipeTrackingFromScrollEventsEnabled()` _macOS_
Returns `Boolean` - Whether the Swipe between pages setting is on.
### `systemPreferences.postNotification(event, userInfo)` _macOS_
* `event` String
* `userInfo` Object
Posts `event` as native notifications of macOS. The `userInfo` is an Object
that contains the user information dictionary sent along with the notification.
### `systemPreferences.postLocalNotification(event, userInfo)` _macOS_
* `event` String
* `userInfo` Object
Posts `event` as native notifications of macOS. The `userInfo` is an Object
that contains the user information dictionary sent along with the notification.
### `systemPreferences.subscribeNotification(event, callback)` _macOS_
* `event` String
* `callback` Function
* `event` String
* `userInfo` Object
Subscribes to native notifications of macOS, `callback` will be called with
`callback(event, userInfo)` when the corresponding `event` happens. The
`userInfo` is an Object that contains the user information dictionary sent
along with the notification.
The `id` of the subscriber is returned, which can be used to unsubscribe the
`event`.
Under the hood this API subscribes to `NSDistributedNotificationCenter`,
example values of `event` are:
* `AppleInterfaceThemeChangedNotification`
* `AppleAquaColorVariantChanged`
* `AppleColorPreferencesChangedNotification`
* `AppleShowScrollBarsSettingChanged`
### `systemPreferences.unsubscribeNotification(id)` _macOS_
* `id` Integer
Removes the subscriber with `id`.
### `systemPreferences.subscribeLocalNotification(event, callback)` _macOS_
* `event` String
* `callback` Function
* `event` String
* `userInfo` Object
Same as `subscribeNotification`, but uses `NSNotificationCenter` for local defaults.
This is necessary for events such as `NSUserDefaultsDidChangeNotification`
### `systemPreferences.unsubscribeLocalNotification(id)` _macOS_
* `id` Integer
Same as `unsubscribeNotification`, but removes the subscriber from `NSNotificationCenter`.
### `systemPreferences.getUserDefault(key, type)` _macOS_
* `key` String
* `type` String - Can be `string`, `boolean`, `integer`, `float`, `double`,
`url`, `array`, `dictionary`
Get the value of `key` in system preferences.
This API uses `NSUserDefaults` on macOS. Some popular `key` and `type`s are:
* `AppleInterfaceStyle`: `string`
* `AppleAquaColorVariant`: `integer`
* `AppleHighlightColor`: `string`
* `AppleShowScrollBars`: `string`
* `NSNavRecentPlaces`: `array`
* `NSPreferredWebServices`: `dictionary`
* `NSUserDictionaryReplacementItems`: `array`
### `systemPreferences.setUserDefault(key, type, value)` _macOS_
* `key` String
* `type` String - See [`getUserDefault`][#systempreferencesgetuserdefaultkey-type-macos]
* `value` String
Set the value of `key` in system preferences.
Note that `type` should match actual type of `value`. An exception is thrown
if they don't.
This API uses `NSUserDefaults` on macOS. Some popular `key` and `type`s are:
* `ApplePressAndHoldEnabled`: `boolean`
### `systemPreferences.isAeroGlassEnabled()` _Windows_
This method returns `true` if [DWM composition][dwm-composition] (Aero Glass) is
enabled, and `false` otherwise.
An example of using it to determine if you should create a transparent window or
not (transparent windows won't work correctly when DWM composition is disabled):
```javascript
const {BrowserWindow, systemPreferences} = require('electron')
let browserOptions = {width: 1000, height: 800}
// Make the window transparent only if the platform supports it.
if (process.platform !== 'win32' || systemPreferences.isAeroGlassEnabled()) {
browserOptions.transparent = true
browserOptions.frame = false
}
// Create the window.
let win = new BrowserWindow(browserOptions)
// Navigate.
if (browserOptions.transparent) {
win.loadURL(`file://${__dirname}/index.html`)
} else {
// No transparency, so we load a fallback that uses basic styles.
win.loadURL(`file://${__dirname}/fallback.html`)
}
```
[dwm-composition]:https://msdn.microsoft.com/en-us/library/windows/desktop/aa969540.aspx
### `systemPreferences.getAccentColor()` _Windows_
Returns `String` - The users current system wide accent color preference in RGBA
hexadecimal form.
```js
const color = systemPreferences.getAccentColor() // `"aabbccdd"`
const red = color.substr(0, 2) // "aa"
const green = color.substr(2, 2) // "bb"
const blue = color.substr(4, 2) // "cc"
const alpha = color.substr(6, 2) // "dd"
```
### `systemPreferences.getColor(color)` _Windows_
* `color` String - One of the following values:
* `3d-dark-shadow` - Dark shadow for three-dimensional display elements.
* `3d-face` - Face color for three-dimensional display elements and for dialog
box backgrounds.
* `3d-highlight` - Highlight color for three-dimensional display elements.
* `3d-light` - Light color for three-dimensional display elements.
* `3d-shadow` - Shadow color for three-dimensional display elements.
* `active-border` - Active window border.
* `active-caption` - Active window title bar. Specifies the left side color in
the color gradient of an active window's title bar if the gradient effect is
enabled.
* `active-caption-gradient` - Right side color in the color gradient of an
active window's title bar.
* `app-workspace` - Background color of multiple document interface (MDI)
applications.
* `button-text` - Text on push buttons.
* `caption-text` - Text in caption, size box, and scroll bar arrow box.
* `desktop` - Desktop background color.
* `disabled-text` - Grayed (disabled) text.
* `highlight` - Item(s) selected in a control.
* `highlight-text` - Text of item(s) selected in a control.
* `hotlight` - Color for a hyperlink or hot-tracked item.
* `inactive-border` - Inactive window border.
* `inactive-caption` - Inactive window caption. Specifies the left side color
in the color gradient of an inactive window's title bar if the gradient
effect is enabled.
* `inactive-caption-gradient` - Right side color in the color gradient of an
inactive window's title bar.
* `inactive-caption-text` - Color of text in an inactive caption.
* `info-background` - Background color for tooltip controls.
* `info-text` - Text color for tooltip controls.
* `menu` - Menu background.
* `menu-highlight` - The color used to highlight menu items when the menu
appears as a flat menu.
* `menubar` - The background color for the menu bar when menus appear as flat
menus.
* `menu-text` - Text in menus.
* `scrollbar` - Scroll bar gray area.
* `window` - Window background.
* `window-frame` - Window frame.
* `window-text` - Text in windows.
Returns `String` - The system color setting in RGB hexadecimal form (`#ABCDEF`).
See the [Windows docs][windows-colors] for more details.
### `systemPreferences.isInvertedColorScheme()` _Windows_
Returns `Boolean` - `true` if an inverted color scheme, such as a high contrast
theme, is active, `false` otherwise.
[windows-colors]:https://msdn.microsoft.com/en-us/library/windows/desktop/ms724371(v=vs.85).aspx