Display macOS window full screen on secondary monitor using Cocoa

Question

I'm working on a Cocoa Mac app where I need to display a window/view on a secondary monitor, full-screen.

I know how to create a window that could be dragged onto the secondary monitor, but I was wanting to programmatically create the window and make it full screen on the external monitor.

Answer 1

First, determine which screen you want to use by iterating over [NSScreen screens].

Create a full screen window with:

NSScreen *screen = /* from [NSScreen screens] */
NSRect screenRect = [screen frame];
NSWindow *window = [[NSWindow alloc] initWithContentRect:screenRect
    styleMask:NSBorderlessWindowMask
    backing:NSBackingStoreBuffered
    defer:NO
    screen:screen];
[window setLevel: CGShieldingWindowLevel()];

You might want to google CGDisplayCapture() as well.

Answer 2

You can call the enterFullScreenMode:withOptions: method of NSView to acheieve the desired behaviour.

See Apple's documentation.

Read here and here for the options that can be supplied to this method.

You can use [NSScreen screens] to get the list of available screens. See here for details.

Answer 3

The full screen window animations are choppy and don't look good in my opinion. The fullscreen view is much smoother.

Try this:

- (void)toggleMyViewFullScreen:(id)sender
{
    if (myView.inFullScreenMode) {
      [myView exitFullScreenModeWithOptions:nil];
    } else {
      NSApplicationPresentationOptions options =
          NSApplicationPresentationHideDock |       
          NSApplicationPresentationHideMenuBar;

      [myView enterFullScreenMode:[NSScreen mainScreen] withOptions:@{
             NSFullScreenModeApplicationPresentationOptions : @(options) }];
                                                                                 }];
    }
}

You can connect this to the fullscreen menu item in the Window menu (after inserting that into your nib) but be sure to change the action that the menu item fires to your toggleMyViewFullScreen: . Or your can invoke toggleMyViewFullScreen programmatically or when your app loads.