Windows QPA: Fix restore geometry after dragging from maximised - Fix

Small adjustment made to previous patch to fix the following issues:
- restoreGeometry not being updated after moving the window from one
screen to the other with keyboard shortcuts.
- restoreGeometry's size not being changed when moving screens if
WM_GETDPISCALEDSIZE isn't sent.

Task-number: QTBUG-112814
Change-Id: I9dd2340137ce57a731f8881d476e902323887e62
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>
(cherry picked from commit 245c2b621f5942861b7f827bfc8a859b9efb9b72)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

src/plugins/platforms/windows/qwindowswindow.cpp

@@ -1954,6 +1954,12 @@ void QWindowsWindow::handleCompositionSettingsChanged()
     }
 }
 
+qreal QWindowsWindow::dpiRelativeScale(const UINT dpi) const
+{
+    return QHighDpiScaling::roundScaleFactor(qreal(dpi) / QWindowsScreen::baseDpi) /
+           QHighDpiScaling::roundScaleFactor(qreal(savedDpi()) / QWindowsScreen::baseDpi);
+}
+
 void QWindowsWindow::handleDpiScaledSize(WPARAM wParam, LPARAM lParam, LRESULT *result)
 {
     // We want to keep QWindow's device independent size constant across the
@@ -1961,9 +1967,8 @@ void QWindowsWindow::handleDpiScaledSize(WPARAM wParam, LPARAM lParam, LRESULT *
     // by the change of DPI (e.g. 120 -> 144 = 1.2), also taking any scale
     // factor rounding into account. The win32 window size includes the margins;
     // add the margins for the new DPI to the window size.
-    const int dpi = int(wParam);
+    const UINT dpi = UINT(wParam);
-    const qreal scale = QHighDpiScaling::roundScaleFactor(qreal(dpi) / QWindowsScreen::baseDpi) /
+    const qreal scale = dpiRelativeScale(dpi);
-                        QHighDpiScaling::roundScaleFactor(qreal(savedDpi()) / QWindowsScreen::baseDpi);
     const QMargins margins = QWindowsGeometryHint::frame(window(), style(), exStyle(), dpi);
     if (!(m_data.flags & Qt::FramelessWindowHint)) {
         // We need to update the custom margins to match the current DPI, because
@@ -1973,10 +1978,6 @@ void QWindowsWindow::handleDpiScaledSize(WPARAM wParam, LPARAM lParam, LRESULT *
         // are currently doing.
         m_data.customMargins *= scale;
     }
-    if (!m_data.restoreGeometry.isEmpty()) {
-        m_data.restoreGeometry.setWidth(m_data.restoreGeometry.width() * scale);
-        m_data.restoreGeometry.setHeight(m_data.restoreGeometry.height() * scale);
-    }
 
     const QSize windowSize = (geometry().size() * scale).grownBy(margins + customMargins());
     SIZE *size = reinterpret_cast<SIZE *>(lParam);
@@ -1988,11 +1989,14 @@ void QWindowsWindow::handleDpiScaledSize(WPARAM wParam, LPARAM lParam, LRESULT *
 void QWindowsWindow::handleDpiChanged(HWND hwnd, WPARAM wParam, LPARAM lParam)
 {
     const UINT dpi = HIWORD(wParam);
+    const qreal scale = dpiRelativeScale(dpi);
     setSavedDpi(dpi);
-
     // Send screen change first, so that the new screen is set during any following resize
     checkForScreenChanged(QWindowsWindow::FromDpiChange);
 
+    if (!IsZoomed(hwnd))
+        m_data.restoreGeometry.setSize(m_data.restoreGeometry.size() * scale);
+
     // We get WM_DPICHANGED in one of two situations:
     //
     // 1. The DPI change is a "spontaneous" DPI change as a result of e.g.
@@ -2030,7 +2034,7 @@ void QWindowsWindow::handleDpiChanged(HWND hwnd, WPARAM wParam, LPARAM lParam)
 void QWindowsWindow::handleDpiChangedAfterParent(HWND hwnd)
 {
     const UINT dpi = GetDpiForWindow(hwnd);
-    const qreal scale = qreal(dpi) / qreal(savedDpi());
+    const qreal scale = dpiRelativeScale(dpi);
     setSavedDpi(dpi);
 
     checkForScreenChanged(QWindowsWindow::FromDpiChange);
@@ -2266,6 +2270,9 @@ void QWindowsWindow::handleGeometryChange()
     if (testFlag(SynchronousGeometryChangeEvent))
         QWindowSystemInterface::flushWindowSystemEvents(QEventLoop::ExcludeUserInputEvents);
 
+    if (!testFlag(ResizeMoveActive))
+        updateRestoreGeometry();
+
     if (!wasSync)
         clearFlag(SynchronousGeometryChangeEvent);
     qCDebug(lcQpaEvents) << __FUNCTION__ << this << window() << m_data.geometry;

src/plugins/platforms/windows/qwindowswindow.h

@@ -345,6 +345,7 @@ public:
 
     void setSavedDpi(int dpi) { m_savedDpi = dpi; }
     int savedDpi() const { return m_savedDpi; }
+    qreal dpiRelativeScale(const UINT dpi) const;
 
 private:
     inline void show_sys() const;