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