Drop call to setPlatformScreen in QHighDpiScaling::setScreenFactor

Drop call to setPlatformScreen since the only affected variables are
logicalDpi and geometry. Replace setPlatformScreen with updateLogicalDpi
which handles global scale factor changes in QScreen.

Call updateGeometriesWithSignals() to check if there are any changes
in geometry or availableGeometry, since the geometry or availableGeometry
can also change when setting a scale factor.

Move setPlatformScreen to QScreen ctor as the function is not used
elsewhere.

Pick-to: 6.4 6.3 6.2
Change-Id: I7acf40bf0643e89a1d9177674d66dc503829f98f
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

src/gui/kernel/qhighdpiscaling.cpp

@@ -555,9 +555,8 @@ void QHighDpiScaling::setScreenFactor(QScreen *screen, qreal factor)
     else
         QHighDpiScaling::m_namedScreenScaleFactors.insert(name, factor);
 
-    // hack to force re-evaluation of screen geometry
     if (screen->handle())
-        screen->d_func()->setPlatformScreen(screen->handle()); // updates geometries based on scale factor
+        screen->d_func()->updateLogicalDpi();
 }
 
 QPoint QHighDpiScaling::mapPositionToNative(const QPoint &pos, const QPlatformScreen *platformScreen)

src/gui/kernel/qplatformscreen.h

@@ -135,7 +135,7 @@ protected:
     QScopedPointer<QPlatformScreenPrivate> d_ptr;
 
 private:
-    friend class QScreenPrivate;
+    friend QScreen;
 };
 
 // Qt doesn't currently support running with no platform screen

src/gui/kernel/qscreen.cpp

@@ -41,7 +41,26 @@ QScreen::QScreen(QPlatformScreen *screen)
     : QObject(*new QScreenPrivate(), nullptr)
 {
     Q_D(QScreen);
-    d->setPlatformScreen(screen);
+    d->platformScreen = screen;
+    d->platformScreen->d_func()->screen = this;
+    d->orientation = d->platformScreen->orientation();
+
+    d->logicalDpi = QPlatformScreen::overrideDpi(d->platformScreen->logicalDpi());
+
+    d->refreshRate = d->platformScreen->refreshRate();
+    // safeguard ourselves against buggy platform behavior...
+    if (d->refreshRate < 1.0)
+        d->refreshRate = 60.0;
+
+    d->updateHighDpi();
+    d->updatePrimaryOrientation(); // derived from the geometry
+}
+
+void QScreenPrivate::updateLogicalDpi()
+{
+    Q_Q(QScreen);
+    logicalDpi = QPlatformScreen::overrideDpi(q->handle()->logicalDpi());
+    updateGeometriesWithSignals(); // updates geometries based on scale factor
 }
 
 void QScreenPrivate::updateGeometriesWithSignals()
@@ -71,25 +90,6 @@ void QScreenPrivate::emitGeometryChangeSignals(bool geometryChanged, bool availa
         emit q->physicalDotsPerInchChanged(q->physicalDotsPerInch());
 }
 
-void QScreenPrivate::setPlatformScreen(QPlatformScreen *screen)
-{
-    Q_Q(QScreen);
-    platformScreen = screen;
-    platformScreen->d_func()->screen = q;
-    orientation = platformScreen->orientation();
-
-    logicalDpi = QPlatformScreen::overrideDpi(platformScreen->logicalDpi());
-
-    refreshRate = platformScreen->refreshRate();
-    // safeguard ourselves against buggy platform behavior...
-    if (refreshRate < 1.0)
-        refreshRate = 60.0;
-
-    updateHighDpi();
-    updatePrimaryOrientation(); // derived from the geometry
-}
-
-
 /*!
     Destroys the screen.
  */

src/gui/kernel/qscreen_p.h

@@ -28,12 +28,12 @@ class QScreenPrivate : public QObjectPrivate
 {
     Q_DECLARE_PUBLIC(QScreen)
 public:
-    void setPlatformScreen(QPlatformScreen *screen);
     void updateHighDpi()
     {
         geometry = platformScreen->deviceIndependentGeometry();
         availableGeometry = QHighDpi::fromNative(platformScreen->availableGeometry(), QHighDpiScaling::factor(platformScreen), geometry.topLeft());
     }
+    void updateLogicalDpi();
 
     void updatePrimaryOrientation();
     void updateGeometriesWithSignals();