Here are some snippets to help with performing different tasks using NSWindow.

Window Characteristics

• Create Borderless Transparent Window: Create a new class that inherits from NSWindow and override the method: – (id) initWithContentRect: (NSRect) contentRect styleMask: (unsigned int) aStyle backing: (NSBackingStoreType) bufferingType defer: (BOOL) flag

  - (id) initWithContentRect: (NSRect) contentRect
                   styleMask: (unsigned int) aStyle
                     backing: (NSBackingStoreType) bufferingType
                       defer: (BOOL) flag
  {
      if (![super initWithContentRect: contentRect 
                               styleMask: NSBorderlessWindowMask 
                            backing: bufferingType 
                           defer: flag]) return nil;
      [self setBackgroundColor: [NSColor clearColor]];
      [self setOpaque:NO];
   
      return self;
  }
  

  Note: This technique allows you to give the user the perception that Core Animation layers are being drawn onto the desktop. It can also be used to create windows that appear to have non-rectangular shapes.