multiple monitors - Determine windows display number and/or layout via java

Question

I have a fullscreen java app that will run on an 8 monitor digital signage type display on a Windows 7 machine. I need to be able to display content on specific physical monitors. Ideally I would like the displays ordered 1-8 in Display Properties -> Settings, however many attempts of unplugging/plugging in and reordering have failed to get the physical monitors to appear in any deterministic order via the Display Properties->Settings. I can reorder them fine, but when my java program retrieves information on the displays it is not in the layout/order that windows has them configured.

GraphicsEnvironment ID returns Strings such as Device0 and Device1, but these do not match the Windows Display numbering as seen in the Display properties. For instance if the layout is 7,4,1,2,3,4,5,6 I still get back Device0, Device1... in which Device0 corresponds to identified screen 1 (not 7 which is the first screen on the left). Is there a way to query the OS to determine what layout the displays are in and/or some other technique to display fullscreen on a specific physical monitor?

Answer 1

You can get the bounds of the screens relative to the big virtual desktop:

GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
for (GraphicsDevice gd : ge.getScreenDevices()) {
    Rectangle bounds = gd.getDefaultConfiguration().getBounds();
    System.out.println(bounds.toString());
}

for my setup this gives:

java.awt.Rectangle[x=0,y=0,width=1280,height=1024]
java.awt.Rectangle[x=1280,y=304,width=1280,height=720]

You can use this information to determine their order. E.g. if you are absolutely sure that your monitors are in a nice grid you can go fullscreen on the upper right monitor like this:

GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
GraphicsDevice gdUpperRight = null;
Rectangle bUpperRight = null;
for (GraphicsDevice gd : ge.getScreenDevices()) {
    Rectangle b = gd.getDefaultConfiguration().getBounds();
    if (bUpperRight == null || b.x > bUpperRight.x || b.y > bUpperRight.y) {
        bUpperRight = b;
        gdUpperRight = gd;
    }
}

gdUpperRight.setFullScreenWindow(myFrame);