Question

Is is possible to make a window act like a true heads up display? If not fully can a windows do any part of the following? Any pointers on finding information about how to code a window like this would be great.

1 – Be above everything?

• All other windows?
• On all spaces?
• Shown above the screensaver? [1]

2 – Be non interactive?

• Never get focus?
• Ignore all mouse clicks? (ie. if the user click where the window is, what ever is under the window receives the click)

[1] Shown above the screen saver would be a user settable preference (default to off). If the display is a big TV and the screen saver slide show is running, the user may sill want the display to be shown.

Answer 1

I’m not sure what you want. If you’re looking for a full screen app here’s Implementing the Full-Screen Experience.

Otherwise, you might be wanting to read Window Layers and Levels

Here’s an exert for convenience:

There are a number of predefined window levels, specified by constants defined by the NSWindow class. The levels you typically use are: NSNormalWindowLevel, which specifies the default level; NSFloatingWindowLevel, which specifies the level for floating palettes; and NSScreenSaverWindowLevel, which specifies the level for a screen saver window. You might also use NSStatusWindowLevel for a status window, or NSModalPanelWindowLevel for a modal panel. If you need to implement your own popup menus you use NSPopUpMenuWindowLevel. The remaining two levels, NSTornOffMenuWindowLevel and NSMainMenuWindowLevel, are reserved for system use.

Oh! And I’m pretty sure you can’t have anything over the screensaver.