QPA: Introduce QPlatformWindow::normalGeometry().

QWidgetWindow stores the normal geometry obtained from the widget when
transiting to other states. This does not work reliably on Windows,
where this geometry is already that of the new state. Instead,
introduce  QPlatformWindow::normalGeometry(), add implementation
for Windows and use that in QWidgetWindow.

Task-number: QTBUG-21371

Change-Id: I3819ebaf55b4e7d2f7eef1affe6c20712ba45d7c
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>

2 files changed, 22 insertions, 8 deletions

diff --git a/src/widgets/kernel/qwidgetwindow.cpp b/src/widgets/kernel/qwidgetwindow.cpp
index c7f8e18118..672c4156cd 100644
--- a/src/widgets/kernel/qwidgetwindow.cpp
+++ b/src/widgets/kernel/qwidgetwindow.cpp
@@ -50,6 +50,7 @@
 #include <private/qwidgetbackingstore_p.h>
 #include <qpa/qwindowsysteminterface_p.h>
 #include <qpa/qplatformtheme.h>
+#include <qpa/qplatformwindow.h>
 #include <private/qgesturemanager_p.h>
 
 QT_BEGIN_NAMESPACE
@@ -547,6 +548,24 @@ void QWidgetWindow::updateGeometry()
     m_widget->data->fstrut_dirty = false;
 }
 
+Qt::WindowState effectiveState(Qt::WindowStates state);
+
+// Store normal geometry used for saving application settings.
+void QWidgetWindow::updateNormalGeometry()
+{
+    QTLWExtra *tle = m_widget->d_func()->maybeTopData();
+    if (!tle)
+        return;
+     // Ask platform window, default to widget geometry.
+    QRect normalGeometry;
+    if (const QPlatformWindow *pw = handle())
+        normalGeometry = pw->normalGeometry();
+    if (!normalGeometry.isValid() && effectiveState(m_widget->windowState()) == Qt::WindowNoState)
+        normalGeometry = m_widget->geometry();
+    if (normalGeometry.isValid())
+        tle->normalGeometry = normalGeometry;
+}
+
 void QWidgetWindow::handleMoveEvent(QMoveEvent *event)
 {
     updateGeometry();
@@ -692,8 +711,6 @@ void QWidgetWindow::handleExposeEvent(QExposeEvent *event)
     }
 }
 
-Qt::WindowState effectiveState(Qt::WindowStates state);
-
 void QWidgetWindow::handleWindowStateChangedEvent(QWindowStateChangeEvent *event)
 {
     // QWindow does currently not know 'active'.
@@ -712,16 +729,12 @@ void QWidgetWindow::handleWindowStateChangedEvent(QWindowStateChangeEvent *event
         widgetState |= Qt::WindowMinimized;
         break;
     case Qt::WindowMaximized:
-        if (effectiveState(widgetState) == Qt::WindowNoState)
-            if (QTLWExtra *tle = m_widget->d_func()->maybeTopData())
-                tle->normalGeometry = m_widget->geometry();
+        updateNormalGeometry();
         widgetState |= Qt::WindowMaximized;
         widgetState &= ~(Qt::WindowMinimized | Qt::WindowFullScreen);
         break;
     case Qt::WindowFullScreen:
-        if (effectiveState(widgetState) == Qt::WindowNoState)
-            if (QTLWExtra *tle = m_widget->d_func()->maybeTopData())
-                tle->normalGeometry = m_widget->geometry();
+        updateNormalGeometry();
         widgetState |= Qt::WindowFullScreen;
         widgetState &= ~(Qt::WindowMinimized);
         break;
diff --git a/src/widgets/kernel/qwidgetwindow_qpa_p.h b/src/widgets/kernel/qwidgetwindow_qpa_p.h
index ffde44dd27..8d6f14a669 100644
--- a/src/widgets/kernel/qwidgetwindow_qpa_p.h
+++ b/src/widgets/kernel/qwidgetwindow_qpa_p.h
@@ -104,6 +104,7 @@ private slots:
 
 private:
     void updateGeometry();
+    void updateNormalGeometry();
 
     enum FocusWidgets {
         FirstFocusWidget,