Windows QPA: Move function to find screen by HWND to QWindowsScreenManager

Task-number: QTBUG-62971
Change-Id: Ida0a8e758723f0f617011a89dc89c266d2506aad
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

3 files changed, 24 insertions, 8 deletions

diff --git a/src/plugins/platforms/windows/qwindowsscreen.cpp b/src/plugins/platforms/windows/qwindowsscreen.cpp
index 3a4793efcd..cfddb3cc71 100644
--- a/src/plugins/platforms/windows/qwindowsscreen.cpp
+++ b/src/plugins/platforms/windows/qwindowsscreen.cpp
@@ -566,4 +566,19 @@ const QWindowsScreen *QWindowsScreenManager::screenAtDp(const QPoint &p) const
     return Q_NULLPTR;
 }
 
+const QWindowsScreen *QWindowsScreenManager::screenForHwnd(HWND hwnd) const
+{
+    HMONITOR hMonitor = MonitorFromWindow(hwnd, MONITOR_DEFAULTTONULL);
+    if (hMonitor == NULL)
+        return nullptr;
+    const auto it =
+        std::find_if(m_screens.cbegin(), m_screens.cend(),
+                     [hMonitor](const QWindowsScreen *s)
+                     {
+                         return s->data().hMonitor == hMonitor
+                             && (s->data().flags & QWindowsScreenData::VirtualDesktop) != 0;
+                     });
+    return it != m_screens.cend() ? *it : nullptr;
+}
+
 QT_END_NAMESPACE
diff --git a/src/plugins/platforms/windows/qwindowsscreen.h b/src/plugins/platforms/windows/qwindowsscreen.h
index 9a8997326b..7cf73f03af 100644
--- a/src/plugins/platforms/windows/qwindowsscreen.h
+++ b/src/plugins/platforms/windows/qwindowsscreen.h
@@ -134,6 +134,7 @@ public:
     const WindowsScreenList &screens() const { return m_screens; }
 
     const QWindowsScreen *screenAtDp(const QPoint &p) const;
+    const QWindowsScreen *screenForHwnd(HWND hwnd) const;
 
 private:
     void removeScreen(int index);
diff --git a/src/plugins/platforms/windows/qwindowswindow.cpp b/src/plugins/platforms/windows/qwindowswindow.cpp
index 5e0fd77776..050829e6f5 100644
--- a/src/plugins/platforms/windows/qwindowswindow.cpp
+++ b/src/plugins/platforms/windows/qwindowswindow.cpp
@@ -1542,15 +1542,15 @@ void QWindowsWindow::handleGeometryChange()
         fireExpose(QRect(QPoint(0, 0), m_data.geometry.size()), true);
     }
     if (!parent() && previousGeometry.topLeft() != m_data.geometry.topLeft()) {
-        HMONITOR hMonitor = MonitorFromWindow(m_data.hwnd, MONITOR_DEFAULTTONULL);
         QPlatformScreen *currentScreen = screen();
-        const auto screens = QWindowsContext::instance()->screenManager().screens();
-        auto newScreenIt = std::find_if(screens.begin(), screens.end(), [&](QWindowsScreen *s) {
-            return s->data().hMonitor == hMonitor
-                && s->data().flags & QWindowsScreenData::VirtualDesktop;
-        });
-        if (newScreenIt != screens.end() && *newScreenIt != currentScreen)
-            QWindowSystemInterface::handleWindowScreenChanged(window(), (*newScreenIt)->screen());
+        const QWindowsScreen *newScreen =
+            QWindowsContext::instance()->screenManager().screenForHwnd(m_data.hwnd);
+        if (newScreen != nullptr && newScreen != currentScreen) {
+            qCDebug(lcQpaWindows).noquote().nospace() << __FUNCTION__
+                << ' ' << window() << " \"" << currentScreen->name()
+                << "\"->\"" << newScreen->name() << '"';
+            QWindowSystemInterface::handleWindowScreenChanged(window(), newScreen->screen());
+        }
     }
     if (testFlag(SynchronousGeometryChangeEvent))
         QWindowSystemInterface::flushWindowSystemEvents(QEventLoop::ExcludeUserInputEvents);