void setup(){
// fullscreen object for main screen + a secondary screen. 
fs = new FullScreen( this, "secondary" ); 

// if you have three screens you can do this: 
// fs = new FullScreen( this, "second", "third" ); 
}

// draw the main sketch
void draw(){
  background( 0 ); 
  // ... 
}


// called by the fullscreen api to initialize the sketch for the 
// secondary screen
void setupSecondary( PApplet sketch ){
  sketch.size( 300, 300 ); 
}

void drawSecondary( PApplet secondary ){
  secondary.background( 255 ); 
  // ... 
}

void mousePressedSecondary( PApplet secondary ){
 // ... 
}

 

void setup(){
  size( 2000, 800 ); // whatever size you want... 
  fs = new FullScreen(); 
  fs.assign( 
    0, new Rectangle( 0, 0, 400, 400 ), // map a 400x400 rectangle to screen 0
    1, new Rectangle( 400, 0, 1600, 800 ) // map a translated 1600x800   rectangle to screen 1 
}


void draw(){
  // draw background things for both screens
  background( 0 ); 


  // translate coordinate system to draw on screen 1
  translate( 400, 0 ); 
}