Programatically detect and setup an external screen?

Question

Hi. Is it possible in Java (or any other language?) to detect if there's an available external screen (on VGA or DVI) and start the screen, and send graphics (text and stuff) to it.

An example: In Powerpoint, if you have an external screen connected, and you go "live" or start the presentation, it will show on the external screen.

I'm working on an app where it should be possible to show different values and info (that changes over time) on an external screen. I'm sure there are other program out there to do that, but now I'm soon done anyways, all I need is to add the external screen feature..

Is this something that differs on Windows, Linux and OS-X?

Answer 1

There might be some hardware specific issues that you will have no control of, so my guess is that it will be impossible to do this reliable for all types of machines, but it might be possible to do for some or even most.

Some laptops that supports an external vga screen will disable (or not enable) it during boot unless there already is a monitor connected (to save power I assume). So if you later want to attach a monitor there will be no signal and you are forced to reboot in order to use an extra monitor. Very annoying, but there is no other workaround. This might be a low end laptop specific problem (?).

So in order to check you have to

• Detect a second display output (should not be a major problem).
• Make sure it is enabled (maybe not always possible?).
• Detect whether the two displays supports displaying different outputs (I guess this should be possible, but I have no idea of how or how difficult). Many laptops will not.