NOTE: some content in this wiki applies only to 0.12 and earlier versions. For official documentation on 0.13 and later, seehttp://docs.nwjs.io

Screen API requires node-webkit >= v0.10.2

Screenis an instance ofEventEmitterobject, and you're able to useScreen.on(...)to respond to native screen's events.

Screenis a singleton object, need to be initiated once by callinggui.Screen.Init()

Init the Screen singleton object, you only need to call this once

Getthe array of screen (number of screen connected to the computer)

screen has following structure:

screen{
// unique id for a screen
id:int,

// physical screen resolution, can be negative, not necessarily start from 0,depending on screen arrangement
bounds:{
x:int,
y:int,
width:int,
height:int
},

// useable area within the screen bound
work_area:{
x:int,
y:int,
width:int,
height:int
},

scaleFactor:float,
isBuiltIn:bool,
rotation:int,
touchSupport:int
}

Screen.chooseDesktopMedia requires nwjs >= v0.12.0
Screen sharing by selection; Currently only working in Windows and OSX and some linux distribution.

DesktopCaptureSourceType:"window" or "screen"
The callback parameter should be a function that looks like this: function(string streamId) {...};
returns falseif the function fails to execute or existing chooseDesktopMedia is still active

Example:

vargui=require('nw.gui');
gui.Screen.Init();// you only need to call this once
gui.Screen.chooseDesktopMedia(["window","screen"],
function(streamId){
varvid_constraint={
mandatory:{
chromeMediaSource:'desktop',
chromeMediaSourceId:streamId,
maxWidth:1920,
maxHeight:1080
},
optional:[]
};
navigator.webkitGetUserMedia({audio:false,video:vid_constraint},success_func,fallback_func);
}
);

More info:https://github.com/nwjs/nw.js/issues/3077

Following events can be listened by usingScreen.on()function, for more information on how to receive events, you can visitEventEmitter.

emitted when the screen resolution, arrangement is changed, the callback is called with 1 argument `screen'

emitted when a new screen added, the callback is called with 1 argument `screen'

emitted when existing screen removed, the callback is called with 1 argument `screen'

functionScreenToString(screen){
varstring="";
string+="screen"+screen.id+"";
varrect=screen.bounds;
string+="bound{"+rect.x+","+rect.y+","+rect.width+","+rect.height+"}";
rect=screen.work_area;
string+="work_area{"+rect.x+","+rect.y+","+rect.width+","+rect.height+"}";
string+="scaleFactor:"+screen.scaleFactor;
string+="isBuiltIn:"+screen.isBuiltIn;
string+="<br>";
returnstring;
}

//init must be called once during startup, before any function to gui.Screen can be called
gui.Screen.Init();
varstring="";
varscreens=gui.Screen.screens;
// store all the screen information into string
for(vari=0;i<screens.length;i++){
string+=ScreenToString(screens[i]);
}

varscreenCB={
onDisplayBoundsChanged:function(screen){
varout="OnDisplayBoundsChanged"+ScreenToString(screen);
},

onDisplayAdded:function(screen){
varout="OnDisplayAdded"+ScreenToString(screen);
},

onDisplayRemoved:function(screen){
varout="OnDisplayRemoved"+ScreenToString(screen);
}
};

// listen to screen events
gui.Screen.on('displayBoundsChanged',screenCB.onDisplayBoundsChanged);
gui.Screen.on('displayAdded',screenCB.onDisplayAdded);
gui.Screen.on('displayRemoved',screenCB.onDisplayRemoved);

Screen.DesktopCaptureMonitor requires nwjs >= v0.12.3

The DesktopCaptureMonitor will start monitoring the system and trigger the below events. The screen may flicker if while DesktopCaptureMonitor is running.

Boolean of whether the DesktopCaptureMonitor is started.

The DesktopCaptureMonitor will stop monitoring the system. The screen may flicker while DesktopCaptureMonitor is running. Theidprovided can be passed intochromeMediaSourceIdingetUserMediaconstraints. DesktopCaptureMonitor should be stopped after a stream is selected.

Following events can be listened by usingScreen.DesktopCaptureMonitor.on()function, for more information on how to receive events, you can visitEventEmitter.

A new source was added.
idis unique id that can be passed as chromeMediaSourceId
nameis the title of the window or screen
orderis the z-order of the windows, if screens are selected they will appear first
typeof the stream: "screen", "window", "other" or "unknown"
primaryon Windows OS only, this will be true if the source is the primary monitor

A source was removed.
idis the chromeMediaSourceId of the screen or monitor that is no longer capturable

The Z-order of a source changed (this may change for windows as others are focused).
idis the chromeMediaSourceId of the screen or window that has changed z-order
new_orderis the new z-order
old_orderis the old z-order

The name of the source has changed. This can happen when a window changes title.
idis the chromeMediaSourceId of the screen or window that has a name changed
nameis the new new name of the screen or window

The thumbnail of a source changed.
idis the chromeMediaSourceId of the screen or window that has an updated thumbnail
thumbnailis the base64 encoded png of the thumbnail

gui.Screen.Init();
gui.Screen.DesktopCaptureMonitor.on("added",function(id,name,order,type){
//select first stream and shutdown
varconstraints={
audio:{//Note: Audio desktop capture only supported in Chromium in WindowsOS
mandatory:{
chromeMediaSource:"system",
chromeMediaSourceId:id
}
},
video:{
mandatory:{
chromeMediaSource:'desktop',
chromeMediaSourceId:id,
}
}
};

// TODO: call getUserMedia with contraints

gui.Screen.DesktopCaptureMonitor.stop();
});

gui.Screen.DesktopCaptureMonitor.on("removed",function(id){});
gui.Screen.DesktopCaptureMonitor.on("orderchanged",function(id,new_order,old_order){});
gui.Screen.DesktopCaptureMonitor.on("namechanged",function(id,name){});
gui.Screen.DesktopCaptureMonitor.on("thumbnailchanged",function(id,thumbnail){});
gui.Screen.DesktopCaptureMonitor.start(true,true);