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>

6 files changed, 61 insertions, 12 deletions

diff --git a/src/gui/kernel/qplatformwindow.cpp b/src/gui/kernel/qplatformwindow.cpp
index fe29627c5a..2364f465b6 100644
--- a/src/gui/kernel/qplatformwindow.cpp
+++ b/src/gui/kernel/qplatformwindow.cpp
@@ -127,6 +127,18 @@ QRect QPlatformWindow::geometry() const
     return d->rect;
 }
 
+/*!
+    Returns the geometry of a window in 'normal' state
+    (neither maximized, fullscreen nor minimized) for saving geometries to
+    application settings.
+
+    \since 5.3
+*/
+QRect QPlatformWindow::normalGeometry() const
+{
+    return QRect();
+}
+
 QMargins QPlatformWindow::frameMargins() const
 {
     return QMargins();
diff --git a/src/gui/kernel/qplatformwindow.h b/src/gui/kernel/qplatformwindow.h
index 7dfbae036f..0adeb223f1 100644
--- a/src/gui/kernel/qplatformwindow.h
+++ b/src/gui/kernel/qplatformwindow.h
@@ -84,6 +84,7 @@ public:
 
     virtual void setGeometry(const QRect &rect);
     virtual QRect geometry() const;
+    virtual QRect normalGeometry() const;
 
     virtual QMargins frameMargins() const;
 
diff --git a/src/plugins/platforms/windows/qwindowswindow.cpp b/src/plugins/platforms/windows/qwindowswindow.cpp
index 5b6fced031..e9ab902966 100644
--- a/src/plugins/platforms/windows/qwindowswindow.cpp
+++ b/src/plugins/platforms/windows/qwindowswindow.cpp
@@ -1234,6 +1234,28 @@ void QWindowsWindow::handleCompositionSettingsChanged()
         applyBlurBehindWindow(handle());
 }
 
+static QRect normalFrameGeometry(HWND hwnd)
+{
+#ifndef Q_OS_WINCE
+    WINDOWPLACEMENT wp;
+    wp.length = sizeof(WINDOWPLACEMENT);
+    if (GetWindowPlacement(hwnd, &wp))
+        return qrectFromRECT(wp.rcNormalPosition);
+#else
+    Q_UNUSED(hwnd)
+#endif
+    return QRect();
+}
+
+QRect QWindowsWindow::normalGeometry() const
+{
+    // Check for fake 'fullscreen' mode.
+    const bool fakeFullScreen = m_savedFrameGeometry.isValid() && window()->windowState() == Qt::WindowFullScreen;
+    const QRect frame = fakeFullScreen ? m_savedFrameGeometry : normalFrameGeometry(m_data.hwnd);
+    const QMargins margins = fakeFullScreen ? QWindowsGeometryHint::frame(m_savedStyle, 0) : frameMargins();
+    return frame.isValid() ? frame.marginsRemoved(margins) : frame;
+}
+
 void QWindowsWindow::setGeometry(const QRect &rectIn)
 {
     QRect rect = rectIn;
@@ -1593,10 +1615,9 @@ void QWindowsWindow::setWindowState_sys(Qt::WindowState newState)
                 m_savedStyle = style();
 #ifndef Q_OS_WINCE
                 if (oldState == Qt::WindowMinimized) {
-                    WINDOWPLACEMENT wp;
-                    wp.length = sizeof(WINDOWPLACEMENT);
-                    if (GetWindowPlacement(m_data.hwnd, &wp))
-                        m_savedFrameGeometry = qrectFromRECT(wp.rcNormalPosition);
+                    const QRect nf = normalFrameGeometry(m_data.hwnd);
+                    if (nf.isValid())
+                        m_savedFrameGeometry = nf;
                 } else {
 #endif
                     m_savedFrameGeometry = frameGeometry_sys();
diff --git a/src/plugins/platforms/windows/qwindowswindow.h b/src/plugins/platforms/windows/qwindowswindow.h
index 3a9516e0e5..99c5761a65 100644
--- a/src/plugins/platforms/windows/qwindowswindow.h
+++ b/src/plugins/platforms/windows/qwindowswindow.h
@@ -162,6 +162,7 @@ public:
     virtual QSurfaceFormat format() const { return m_format; }
     virtual void setGeometry(const QRect &rect);
     virtual QRect geometry() const { return m_data.geometry; }
+    QRect normalGeometry() const Q_DECL_OVERRIDE;
 
     virtual void setVisible(bool visible);
     bool isVisible() const;
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,