How to detect window state in linux? - linux

Question

I need to find out if a native linux application window is maximized or minimized in a java program.
I tried using X11.XGetWindowProperty() and I get some results also, but I cant make out any useful information in it.
I am using JNA 4.2.1, Java 8 update72 on Ubuntu 14.04 LTS. Any pointers will be very helpful. Thanks in advance to all.
[Edit]
I have the code below which gives me the result I need. But the result is not same for every invocation. The atoms which are returned for the window vary within invocations. Is there any other reliable way to get the window state?
private static X11 x11 = X11.INSTANCE;
private static Display dispy = x11.XOpenDisplay(null);
public static void main(String[] args) {
try {
X11.Atom[] atoms = getAtomProperties(
bytesToInt(getProperty(X11.XA_ATOM, X11.INSTANCE.XInternAtom(dispy, "_NET_WM_STATE", false))));
boolean hidden = false;
boolean vmax = false;
boolean hmax = false;
for (int i = 0; i < atoms.length; i++) {
X11.Atom atom = atoms[i];
if (atom == null)
continue;
String atomName = X11.INSTANCE.XGetAtomName(dispy, atom);
if ("_NET_WM_STATE_HIDDEN".equals(atomName)) {
hidden = true;
} else if ("_NET_WM_STATE_MAXIMIZED_VERT".equals(atomName)) {
vmax = true;
} else if ("_NET_WM_STATE_MAXIMIZED_HORZ".equals(atomName)) {
hmax = true;
}
}
if (hidden)
System.out.println("Window minimized");
else if (vmax && hmax && !hidden)
System.out.println("Window maximized");
else
System.out.println("Window normal");
} catch (X11Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
private static X11.Atom[] getAtomProperties(int[] ids) {
X11.Atom[] atoms = new X11.Atom[ids.length];
for (int i = 0; i < ids.length; i++) {
if (ids[i] == 0)
continue;
atoms[i] = new X11.Atom(ids[i]);
}
return atoms;
}
private static int[] bytesToInt(byte[] prop) {
if (prop == null)
return null;
int[] res = new int[prop.length / 4];
for (int i = 0; i < res.length; i++) {
res[i] = ((prop[i * 4 + 3] & 0xff) << 24) | ((prop[i * 4 + 2] & 0xff) << 16) | ((prop[i * 4 + 1] & 0xff) << 8)
| ((prop[i * 4 + 0] & 0xff));
if (res[i] != 0)
continue;
}
return res;
}
private static byte[] getProperty(X11.Atom xa_prop_type, X11.Atom xa_prop_name) throws X11Exception {
X11.Window window = new X11.Window(73400355);
X11.AtomByReference xa_ret_type_ref = new X11.AtomByReference();
IntByReference ret_format_ref = new IntByReference();
NativeLongByReference ret_nitems_ref = new NativeLongByReference();
NativeLongByReference ret_bytes_after_ref = new NativeLongByReference();
PointerByReference ret_prop_ref = new PointerByReference();
NativeLong long_offset = new NativeLong(0);
NativeLong long_length = new NativeLong(4096 / 4);
/*
* MAX_PROPERTY_VALUE_LEN / 4 explanation (XGetWindowProperty manpage):
*
* long_length = Specifies the length in 32-bit multiples of the data to be retrieved.
*/
if (x11.XGetWindowProperty(dispy, window, xa_prop_name, long_offset, long_length, false, xa_prop_type, xa_ret_type_ref,
ret_format_ref, ret_nitems_ref, ret_bytes_after_ref, ret_prop_ref) != X11.Success) {
String prop_name = x11.XGetAtomName(dispy, xa_prop_name);
throw new X11Exception("Cannot get " + prop_name + " property.");
}
X11.Atom xa_ret_type = xa_ret_type_ref.getValue();
Pointer ret_prop = ret_prop_ref.getValue();
if (xa_ret_type == null) {
// the specified property does not exist for the specified window
return null;
}
if (xa_ret_type == null || xa_prop_type == null || !xa_ret_type.toNative().equals(xa_prop_type.toNative())) {
x11.XFree(ret_prop);
String prop_name = x11.XGetAtomName(dispy, xa_prop_name);
throw new X11Exception("Invalid type of " + prop_name + " property");
}
int ret_format = ret_format_ref.getValue();
long ret_nitems = ret_nitems_ref.getValue().longValue();
// null terminate the result to make string handling easier
int nbytes;
if (ret_format == 32)
nbytes = Native.LONG_SIZE;
else if (ret_format == 16)
nbytes = Native.LONG_SIZE / 2;
else if (ret_format == 8)
nbytes = 1;
else if (ret_format == 0)
nbytes = 0;
else
throw new X11Exception("Invalid return format");
int length = Math.min((int) ret_nitems * nbytes, 4096);
byte[] ret = ret_prop.getByteArray(0, length);
x11.XFree(ret_prop);
return ret;
}