Restore support for -title command line argument on X11, add -qwindowtitle.

-title disappeared between Qt4 and Qt5, due to all the refactorings around QPA.
Making the caption of the mainwindow configurable allows custom setups
for specific users or use cases.

[ChangeLog][QtGui][QGuiApplication] Restore support for -title command line
argument on X11, add -qwindowtitle on all platforms.

Change-Id: I73e6bf21248f3419178eba583b257172a175e74e
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Albert Astals Cid <albert.astals@canonical.com>
Reviewed-by: Paul Olav Tvete <paul.tvete@digia.com>
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@digia.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/src/gui/kernel/qwindow.cpp b/src/gui/kernel/qwindow.cpp
index 42f61399d9..2382764183 100644
--- a/src/gui/kernel/qwindow.cpp
+++ b/src/gui/kernel/qwindow.cpp
@@ -432,6 +432,14 @@ void QWindow::setVisible(bool visible)
         // remove posted quit events when showing a new window
         QCoreApplication::removePostedEvents(qApp, QEvent::Quit);
 
+        if (type() == Qt::Window) {
+            QString &firstWindowTitle = QGuiApplicationPrivate::instance()->firstWindowTitle;
+            if (!firstWindowTitle.isEmpty()) {
+                setTitle(firstWindowTitle);
+                firstWindowTitle = QString();
+            }
+        }
+
         QShowEvent showEvent;
         QGuiApplication::sendEvent(this, &showEvent);
     }