Support _NET_WORKAREA on Xinerama setups in QDesktopWidget

Instead of ignoring _NET_WORKAREA, merge it with each screen geometry
to give a meaningful availableGeometry() for all screens.

Reviewed-by: denis

2 files changed, 28 insertions, 10 deletions

diff --git a/src/gui/kernel/qdesktopwidget_x11.cpp b/src/gui/kernel/qdesktopwidget_x11.cpp
index 1555fc034d..8b0c215ced 100644
--- a/src/gui/kernel/qdesktopwidget_x11.cpp
+++ b/src/gui/kernel/qdesktopwidget_x11.cpp
@@ -285,26 +285,36 @@ const QRect QDesktopWidget::availableGeometry(int screen) const
     if (d->workareas[screen].isValid())
         return d->workareas[screen];
 
-    if ((d->screenCount == 1 || !isVirtualDesktop())
-        && X11->isSupportedByWM(ATOM(_NET_WORKAREA))) {
+    if (X11->isSupportedByWM(ATOM(_NET_WORKAREA))) {
+        int x11Screen = isVirtualDesktop() ? DefaultScreen(X11->display) : screen;
+
         Atom ret;
         int format, e;
         unsigned char *data = 0;
         unsigned long nitems, after;
 
         e = XGetWindowProperty(X11->display,
-                                QX11Info::appRootWindow(screen),
-                                ATOM(_NET_WORKAREA), 0, 4, False, XA_CARDINAL,
-                                &ret, &format, &nitems, &after, &data);
+                               QX11Info::appRootWindow(x11Screen),
+                               ATOM(_NET_WORKAREA), 0, 4, False, XA_CARDINAL,
+                               &ret, &format, &nitems, &after, &data);
 
+        QRect workArea;
         if (e == Success && ret == XA_CARDINAL &&
             format == 32 && nitems == 4) {
             long *workarea = (long *) data;
-            d->workareas[screen].setRect(workarea[0], workarea[1],
-                                          workarea[2], workarea[3]);
+            workArea = QRect(workarea[0], workarea[1], workarea[2], workarea[3]);
         } else {
-            d->workareas[screen] = screenGeometry(screen);
+            workArea = screenGeometry(screen);
+        }
+
+        if (isVirtualDesktop()) {
+            // intersect the workarea (which spawns all Xinerama screens) with the rect for the
+            // requested screen
+            workArea &= screenGeometry(screen);
         }
+
+        d->workareas[screen] = workArea;
+
         if (data)
             XFree(data);
     } else {
diff --git a/tests/auto/qdesktopwidget/tst_qdesktopwidget.cpp b/tests/auto/qdesktopwidget/tst_qdesktopwidget.cpp
index c6fac8d466..d2b0d8a476 100644
--- a/tests/auto/qdesktopwidget/tst_qdesktopwidget.cpp
+++ b/tests/auto/qdesktopwidget/tst_qdesktopwidget.cpp
@@ -99,9 +99,17 @@ void tst_QDesktopWidget::availableGeometry()
 {
     QDesktopWidget desktop;
 
-    QRect total = desktop.screenGeometry();
-    QRect available = desktop.availableGeometry();
+    QRect total;
+    QRect available;
 
+    for (int i = 0; i < desktop.screenCount(); ++i) {
+        total = desktop.screenGeometry(i);
+        available = desktop.availableGeometry(i);
+        QVERIFY(total.contains(available));
+    }
+
+    total = desktop.screenGeometry();
+    available = desktop.availableGeometry();
     QVERIFY(total.contains(available));
     QCOMPARE(desktop.availableGeometry(desktop.primaryScreen()), available);
     QCOMPARE(desktop.screenGeometry(desktop.primaryScreen()), total);