iTunes-style NSWindow subclass?

Question

Is there an open-source library for Cocoa to create a window following iTunes\' style? That is the window controls are laid out vertically instead of horizontally:

Answer 1

Just a modified version based on @Regexident 's for new macOS. The view hierarchy changed for new macOS UI, so the original version does not work. The modified code is as follows (works on macOS 10.13):

- (void)verticalizeButtonsForWindow:(NSWindow *)aWindow {
    // New view hierarchy.
    NSView *titleBarContainerView = aWindow.contentView.superview.subviews[1];
    titleBarContainerView.frame = NSMakeRect(titleBarContainerView.frame.origin.x, titleBarContainerView.frame.origin.y - 60.0 + titleBarContainerView.frame.size.height, titleBarContainerView.frame.size.width, 60.0);
    NSView *titleBarView = titleBarContainerView.subviews[0];
    titleBarView.frame = NSMakeRect(0.0, 0.0, titleBarView.frame.size.width, 60.0);
    NSArray *titleBarSubviews = titleBarView.subviews;

    NSView *closeButton = [titleBarSubviews objectAtIndex:0];
    NSRect closeButtonFrame = [closeButton frame];

    NSView *minimizeButton = [titleBarSubviews objectAtIndex:2];
    NSRect minimizeButtonFrame = [minimizeButton frame];

    NSView *zoomButton = [titleBarSubviews objectAtIndex:1];
    NSRect zoomButtonFrame = [zoomButton frame];

    // Coordinate changed: add instead of minus.
    [minimizeButton setFrame:NSMakeRect(closeButtonFrame.origin.x, closeButtonFrame.origin.y + 20.0, minimizeButtonFrame.size.width, minimizeButtonFrame.size.height)];
    [zoomButton setFrame:NSMakeRect(closeButtonFrame.origin.x, closeButtonFrame.origin.y + 40.0, zoomButtonFrame.size.width, zoomButtonFrame.size.height)];
}

Result screenshot: