Remove usage of QDesktopWidget(Private) from most places in QtWidgets

Call QGuiApplication and QScreen APIs directly to get geometries, and
make use of QScreen::grabWindow grabbing the screen it's called on when
called with WId == 0.

This assumes that QGuiApplication::screen and QWidget::screen never
return nullptr, which is already assumed in other places.

In QSplashScreen, simplify the code to operate on the screen of the
QSplashScreen itself. Remove the case that handles a QDesktopWidget
parent - QSplashScreen doesn't have a constructor that takes a
QWidget* parent anymore.

In the QEffect implementation, we can rely on the widget pointer
not being nullptr (it's tested in the free functions client code
uses).

Includes a few drive-by changes to coding style and logic in
qtooltip.cpp, where the tip label placement now prefers the screen
of the widget the label is created for, and uses the position only
as a fallback.

What remains is the special handling of QDesktopWidget and the
Qt::Desktop type in QWidget and QApplication.

Change-Id: I30b67bab8ae82ddfcc7bbbec3c10f6e935b74f06
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>

24 files changed, 130 insertions, 191 deletions

diff --git a/src/widgets/dialogs/qcolordialog.cpp b/src/widgets/dialogs/qcolordialog.cpp
index 8e5895f48b..30c81f8c0e 100644
--- a/src/widgets/dialogs/qcolordialog.cpp
+++ b/src/widgets/dialogs/qcolordialog.cpp
@@ -40,7 +40,6 @@
 #include "qcolordialog.h"
 
 #include "qapplication.h"
-#include <private/qdesktopwidget_p.h>
 #include "qdrawutil.h"
 #include "qevent.h"
 #include "qimage.h"
@@ -1564,9 +1563,11 @@ bool QColorDialogPrivate::selectColor(const QColor &col)
 
 QColor QColorDialogPrivate::grabScreenColor(const QPoint &p)
 {
-    const QWidget *desktop = QApplication::desktop();
-    const QPixmap pixmap = QGuiApplication::primaryScreen()->grabWindow(desktop->winId(), p.x(), p.y(), 1, 1);
-    QImage i = pixmap.toImage();
+    QScreen *screen = QGuiApplication::screenAt(p);
+    if (!screen)
+        screen = QGuiApplication::primaryScreen();
+    const QPixmap pixmap = screen->grabWindow(0, p.x(), p.y(), 1, 1);
+    const QImage i = pixmap.toImage();
     return i.pixel(0, 0);
 }
 
@@ -1758,7 +1759,7 @@ void QColorDialogPrivate::initWidgets()
     } else {
         // better color picker size for small displays
 #if defined(QT_SMALL_COLORDIALOG)
-        QSize screenSize = QDesktopWidgetPrivate::availableGeometry(QCursor::pos()).size();
+        QSize screenSize = QGuiApplication::screenAt(QCursor::pos())->availableGeometry().size();
         pWidth = pHeight = qMin(screenSize.width(), screenSize.height());
         pHeight -= 20;
         if(screenSize.height() > screenSize.width())
diff --git a/src/widgets/dialogs/qdialog.cpp b/src/widgets/dialogs/qdialog.cpp
index 0f0e213e71..52976611aa 100644
--- a/src/widgets/dialogs/qdialog.cpp
+++ b/src/widgets/dialogs/qdialog.cpp
@@ -49,7 +49,6 @@
 #endif
 
 #include "qevent.h"
-#include <private/qdesktopwidget_p.h>
 #include "qapplication.h"
 #include "qlayout.h"
 #if QT_CONFIG(sizegrip)
@@ -872,23 +871,23 @@ void QDialog::showEvent(QShowEvent *event)
 /*! \internal */
 void QDialog::adjustPosition(QWidget* w)
 {
-
     if (const QPlatformTheme *theme = QGuiApplicationPrivate::platformTheme())
         if (theme->themeHint(QPlatformTheme::WindowAutoPlacement).toBool())
             return;
     QPoint p(0, 0);
-    int extraw = 0, extrah = 0, scrn = 0;
+    int extraw = 0, extrah = 0;
     if (w)
         w = w->window();
     QRect desk;
-    if (w) {
-        scrn = QDesktopWidgetPrivate::screenNumber(w);
-    } else if (QGuiApplication::primaryScreen()->virtualSiblings().size() > 1) {
-        scrn = QDesktopWidgetPrivate::screenNumber(QCursor::pos());
-    } else {
-        scrn = QDesktopWidgetPrivate::screenNumber(this);
-    }
-    desk = QDesktopWidgetPrivate::availableGeometry(scrn);
+    QScreen *scrn = nullptr;
+    if (w)
+        scrn = w->screen();
+    else if (QGuiApplication::primaryScreen()->virtualSiblings().size() > 1)
+        scrn = QGuiApplication::screenAt(QCursor::pos());
+    else
+        scrn = screen();
+    if (scrn)
+        desk = scrn->availableGeometry();
 
     QWidgetList list = QApplication::topLevelWidgets();
     for (int i = 0; (extraw == 0 || extrah == 0) && i < list.size(); ++i) {
@@ -942,9 +941,9 @@ void QDialog::adjustPosition(QWidget* w)
     // QTBUG-52735: Manually set the correct target screen since scaling in a
     // subsequent call to QWindow::resize() may otherwise use the wrong factor
     // if the screen changed notification is still in an event queue.
-    if (scrn >= 0) {
+    if (scrn) {
         if (QWindow *window = windowHandle())
-            window->setScreen(QGuiApplication::screens().at(scrn));
+            window->setScreen(scrn);
     }
 
     move(p);
diff --git a/src/widgets/dialogs/qmessagebox.cpp b/src/widgets/dialogs/qmessagebox.cpp
index e0edc2f755..22d86b301a 100644
--- a/src/widgets/dialogs/qmessagebox.cpp
+++ b/src/widgets/dialogs/qmessagebox.cpp
@@ -64,7 +64,6 @@
 #include <QtGui/qfontmetrics.h>
 #include <QtGui/qclipboard.h>
 #include "private/qabstractbutton_p.h"
-#include <private/qdesktopwidget_p.h>
 
 #ifdef Q_OS_WIN
 #    include <QtCore/qt_windows.h>
@@ -363,7 +362,7 @@ void QMessageBoxPrivate::updateSize()
     if (!q->isVisible())
         return;
 
-    QSize screenSize = QDesktopWidgetPrivate::availableGeometry(QCursor::pos()).size();
+    const QSize screenSize = QGuiApplication::screenAt(QCursor::pos())->availableGeometry().size();
     int hardLimit = qMin(screenSize.width() - 480, 1000); // can never get bigger than this
     // on small screens allows the messagebox be the same size as the screen
     if (screenSize.width() <= 1024)
diff --git a/src/widgets/dialogs/qwizard.cpp b/src/widgets/dialogs/qwizard.cpp
index 0860f9defe..2548a668ce 100644
--- a/src/widgets/dialogs/qwizard.cpp
+++ b/src/widgets/dialogs/qwizard.cpp
@@ -47,7 +47,6 @@
 #include "qapplication.h"
 #include "qboxlayout.h"
 #include "qlayoutitem.h"
-#include <private/qdesktopwidget_p.h>
 #include "qevent.h"
 #include "qframe.h"
 #include "qlabel.h"
diff --git a/src/widgets/kernel/qtooltip.cpp b/src/widgets/kernel/qtooltip.cpp
index af5fbadf22..a57ede6059 100644
--- a/src/widgets/kernel/qtooltip.cpp
+++ b/src/widgets/kernel/qtooltip.cpp
@@ -40,7 +40,6 @@
 #include <QtWidgets/private/qtwidgetsglobal_p.h>
 
 #include <qapplication.h>
-#include <private/qdesktopwidget_p.h>
 #include <qevent.h>
 #include <qpointer.h>
 #include <qstyle.h>
@@ -167,11 +166,11 @@ private:
 QTipLabel *QTipLabel::instance = nullptr;
 
 QTipLabel::QTipLabel(const QString &text, const QPoint &pos, QWidget *w, int msecDisplayTime)
+    : QLabel(w, Qt::ToolTip | Qt::BypassGraphicsProxyWidget)
 #ifndef QT_NO_STYLE_STYLESHEET
-    : QLabel(w, Qt::ToolTip | Qt::BypassGraphicsProxyWidget), styleSheetParent(nullptr), widget(nullptr)
-#else
-    : QLabel(w, Qt::ToolTip | Qt::BypassGraphicsProxyWidget), widget(0)
+    , styleSheetParent(nullptr)
 #endif
+    , widget(nullptr)
 {
     delete instance;
     instance = this;
@@ -225,15 +224,10 @@ void  QTipLabel::updateSize(const QPoint &pos)
         ++extra.rheight();
     setWordWrap(Qt::mightBeRichText(text()));
     QSize sh = sizeHint();
-    QScreen *screen = windowHandle() ? windowHandle()->screen() : QGuiApplication::screenAt(pos);
-    if (!screen)
-        screen = QGuiApplication::primaryScreen();
-    if (screen) {
-        const qreal screenWidth = screen->geometry().width();
-        if (!wordWrap() && sh.width() > screenWidth) {
-            setWordWrap(true);
-            sh = sizeHint();
-        }
+    const QScreen *screen = getTipScreen(pos, this);
+    if (!wordWrap() && sh.width() > screen->geometry().width()) {
+        setWordWrap(true);
+        sh = sizeHint();
     }
     resize(sh + extra);
 }
@@ -367,10 +361,7 @@ bool QTipLabel::eventFilter(QObject *o, QEvent *e)
 
 QScreen *QTipLabel::getTipScreen(const QPoint &pos, QWidget *w)
 {
-    int screenNo = QGuiApplication::primaryScreen()->virtualSiblings().size() > 1
-                 ? QDesktopWidgetPrivate::screenNumber(pos)
-                 : QDesktopWidgetPrivate::screenNumber(w);
-    return QDesktopWidgetPrivate::screen(screenNo);
+    return w ? w->screen() : QGuiApplication::primaryScreen()->virtualSiblingAt(pos);
 }
 
 void QTipLabel::placeTip(const QPoint &pos, QWidget *w)
@@ -463,12 +454,11 @@ bool QTipLabel::tipChanged(const QPoint &pos, const QString &text, QObject *o)
 
 void QToolTip::showText(const QPoint &pos, const QString &text, QWidget *w, const QRect &rect, int msecDisplayTime)
 {
-    if (QTipLabel::instance && QTipLabel::instance->isVisible()){ // a tip does already exist
+    if (QTipLabel::instance && QTipLabel::instance->isVisible()) { // a tip does already exist
         if (text.isEmpty()){ // empty text means hide current tip
             QTipLabel::instance->hideTip();
             return;
-        }
-        else if (!QTipLabel::instance->fadingOut){
+        } else if (!QTipLabel::instance->fadingOut) {
             // If the tip has changed, reuse the one
             // that is showing (removes flickering)
             QPoint localPos = pos;
@@ -483,24 +473,23 @@ void QToolTip::showText(const QPoint &pos, const QString &text, QWidget *w, cons
         }
     }
 
-    if (!text.isEmpty()){ // no tip can be reused, create new tip:
-        QWidget *tipLabelParent = [pos, w]() -> QWidget* {
+    if (!text.isEmpty()) { // no tip can be reused, create new tip:
+        QWidget *tipLabelParent = [w]() -> QWidget* {
 #ifdef Q_OS_WIN32
             // On windows, we can't use the widget as parent otherwise the window will be
             // raised when the tooltip will be shown
-            QScreen *screen = QTipLabel::getTipScreen(pos, w);
-            return QApplication::desktop(screen);
+            Q_UNUSED(w);
+            return nullptr;
 #else
-            Q_UNUSED(pos);
             return w;
 #endif
         }();
         new QTipLabel(text, pos, tipLabelParent, msecDisplayTime); // sets QTipLabel::instance to itself
+        QWidgetPrivate::get(QTipLabel::instance)->setScreen(QTipLabel::getTipScreen(pos, w));
         QTipLabel::instance->setTipRect(w, rect);
         QTipLabel::instance->placeTip(pos, w);
         QTipLabel::instance->setObjectName(QLatin1String("qtooltip_label"));
 
-
 #if QT_CONFIG(effects)
         if (QApplication::isEffectEnabled(Qt::UI_FadeTooltip))
             qFadeEffect(QTipLabel::instance);
diff --git a/src/widgets/kernel/qwhatsthis.cpp b/src/widgets/kernel/qwhatsthis.cpp
index c5a9989837..7ca50f9dab 100644
--- a/src/widgets/kernel/qwhatsthis.cpp
+++ b/src/widgets/kernel/qwhatsthis.cpp
@@ -41,7 +41,7 @@
 #include "qpointer.h"
 #include "qapplication.h"
 #include <private/qguiapplication_p.h>
-#include <private/qdesktopwidget_p.h>
+#include "qwidget.h"
 #include "qevent.h"
 #include "qpixmap.h"
 #include "qscreen.h"
@@ -235,8 +235,7 @@ QWhatsThat::~QWhatsThat()
 
 void QWhatsThat::showEvent(QShowEvent *)
 {
-    background = QGuiApplication::primaryScreen()->grabWindow(QApplication::desktop()->internalWinId(),
-                                                              x(), y(), width(), height());
+    background = QGuiApplication::primaryScreen()->grabWindow(0, x(), y(), width(), height());
 }
 
 void QWhatsThat::mousePressEvent(QMouseEvent* e)
@@ -579,16 +578,16 @@ void QWhatsThisPrivate::say(QWidget * widget, const QString &text, int x, int y)
     QWhatsThat *whatsThat = new QWhatsThat(text, nullptr, widget);
 
     // okay, now to find a suitable location
-    int scr = (widget ?
-                QDesktopWidgetPrivate::screenNumber(widget) :
-                QDesktopWidgetPrivate::screenNumber(QPoint(x,y))
-               );
-    QRect screen = QDesktopWidgetPrivate::screenGeometry(scr);
+    QScreen *screen = widget ? widget->screen()
+                             : QGuiApplication::screenAt(QPoint(x, y));
+    if (!screen)
+        screen = QGuiApplication::primaryScreen();
+    QRect screenRect = screen->geometry();
 
     int w = whatsThat->width();
     int h = whatsThat->height();
-    int sx = screen.x();
-    int sy = screen.y();
+    int sx = screenRect.x();
+    int sy = screenRect.y();
 
     // first try locating the widget immediately above/below,
     // with nice alignment if possible.
@@ -601,13 +600,13 @@ void QWhatsThisPrivate::say(QWidget * widget, const QString &text, int x, int y)
     else
         x = x - w/2;
 
-        // squeeze it in if that would result in part of what's this
-        // being only partially visible
-    if (x + w  + shadowWidth > sx+screen.width())
-        x = (widget? (qMin(screen.width(),
-                           pos.x() + widget->width())
-                     ) : screen.width())
+    // squeeze it in if that would result in part of what's this
+    // being only partially visible
+    if (x + w  + shadowWidth > sx+screenRect.width()) {
+        x = (widget ? qMin(screenRect.width(), pos.x() + widget->width())
+                    : screenRect.width())
             - w;
+    }
 
     if (x < sx)
         x = sx;
@@ -615,18 +614,18 @@ void QWhatsThisPrivate::say(QWidget * widget, const QString &text, int x, int y)
     if (widget && h > widget->height() + 16) {
         y = pos.y() + widget->height() + 2; // below, two pixels spacing
         // what's this is above or below, wherever there's most space
-        if (y + h + 10 > sy+screen.height())
+        if (y + h + 10 > sy + screenRect.height())
             y = pos.y() + 2 - shadowWidth - h; // above, overlap
     }
     y = y + 2;
 
-        // squeeze it in if that would result in part of what's this
-        // being only partially visible
-    if (y + h + shadowWidth > sy+screen.height())
-        y = (widget ? (qMin(screen.height(),
-                             pos.y() + widget->height())
-                       ) : screen.height())
+    // squeeze it in if that would result in part of what's this
+    // being only partially visible
+    if (y + h + shadowWidth > sy + screenRect.height()) {
+        y = (widget ? qMin(screenRect.height(), pos.y() + widget->height())
+                    : screenRect.height())
             - h;
+    }
     if (y < sy)
         y = sy;
 
diff --git a/src/widgets/util/qcompleter.cpp b/src/widgets/util/qcompleter.cpp
index 3083889954..cdd06f4790 100644
--- a/src/widgets/util/qcompleter.cpp
+++ b/src/widgets/util/qcompleter.cpp
@@ -158,7 +158,7 @@
 #include "QtWidgets/qapplication.h"
 #include "QtGui/qevent.h"
 #include <private/qapplication_p.h>
-#include <private/qdesktopwidget_p.h>
+#include <private/qwidget_p.h>
 #if QT_CONFIG(lineedit)
 #include "QtWidgets/qlineedit.h"
 #endif
diff --git a/src/widgets/util/qscroller.cpp b/src/widgets/util/qscroller.cpp
index 003f27de56..b94d8f4b81 100644
--- a/src/widgets/util/qscroller.cpp
+++ b/src/widgets/util/qscroller.cpp
@@ -57,7 +57,6 @@
 #include <QGraphicsScene>
 #include <QGraphicsView>
 #endif
-#include <private/qdesktopwidget_p.h>
 #include <QVector2D>
 #include <QtCore/qmath.h>
 #include <QtGui/qevent.h>
diff --git a/src/widgets/util/qsystemtrayicon.cpp b/src/widgets/util/qsystemtrayicon.cpp
index 9e49b1ec57..556427387f 100644
--- a/src/widgets/util/qsystemtrayicon.cpp
+++ b/src/widgets/util/qsystemtrayicon.cpp
@@ -60,7 +60,6 @@
 #include "qstyle.h"
 #include "qgridlayout.h"
 #include "qapplication.h"
-#include <private/qdesktopwidget_p.h>
 #include "qbitmap.h"
 
 #include <private/qhighdpiscaling_p.h>
@@ -599,12 +598,15 @@ void QBalloonTip::resizeEvent(QResizeEvent *ev)
 void QBalloonTip::balloon(const QPoint& pos, int msecs, bool showArrow)
 {
     this->showArrow = showArrow;
-    QRect scr = QDesktopWidgetPrivate::screenGeometry(pos);
+    QScreen *screen = QGuiApplication::screenAt(pos);
+    if (!screen)
+        screen = QGuiApplication::primaryScreen();
+    QRect screenRect = screen->geometry();
     QSize sh = sizeHint();
     const int border = 1;
     const int ah = 18, ao = 18, aw = 18, rc = 7;
-    bool arrowAtTop = (pos.y() + sh.height() + ah < scr.height());
-    bool arrowAtLeft = (pos.x() + sh.width() - ao < scr.width());
+    bool arrowAtTop = (pos.y() + sh.height() + ah < screenRect.height());
+    bool arrowAtLeft = (pos.x() + sh.width() - ao < screenRect.width());
     setContentsMargins(border + 3,  border + (arrowAtTop ? ah : 0) + 2, border + 3, border + (arrowAtTop ? 0 : ah) + 2);
     updateGeometry();
     sh  = sizeHint();
@@ -630,14 +632,14 @@ void QBalloonTip::balloon(const QPoint& pos, int msecs, bool showArrow)
             path.lineTo(ml + ao, mt - ah);
             path.lineTo(ml + ao + aw, mt);
         }
-        move(qMax(pos.x() - ao, scr.left() + 2), pos.y());
+        move(qMax(pos.x() - ao, screenRect.left() + 2), pos.y());
     } else if (arrowAtTop && !arrowAtLeft) {
         if (showArrow) {
             path.lineTo(mr - ao - aw, mt);
             path.lineTo(mr - ao, mt - ah);
             path.lineTo(mr - ao, mt);
         }
-        move(qMin(pos.x() - sh.width() + ao, scr.right() - sh.width() - 2), pos.y());
+        move(qMin(pos.x() - sh.width() + ao, screenRect.right() - sh.width() - 2), pos.y());
     }
     path.lineTo(mr - rc, mt);
     path.arcTo(QRect(mr - rc*2, mt, rc*2, rc*2), 90, -90);
@@ -649,7 +651,7 @@ void QBalloonTip::balloon(const QPoint& pos, int msecs, bool showArrow)
             path.lineTo(mr - ao, mb + ah);
             path.lineTo(mr - ao - aw, mb);
         }
-        move(qMin(pos.x() - sh.width() + ao, scr.right() - sh.width() - 2),
+        move(qMin(pos.x() - sh.width() + ao, screenRect.right() - sh.width() - 2),
              pos.y() - sh.height());
     } else if (!arrowAtTop && arrowAtLeft) {
         if (showArrow) {
@@ -657,7 +659,7 @@ void QBalloonTip::balloon(const QPoint& pos, int msecs, bool showArrow)
             path.lineTo(ao, mb + ah);
             path.lineTo(ao, mb);
         }
-        move(qMax(pos.x() - ao, scr.x() + 2), pos.y() - sh.height());
+        move(qMax(pos.x() - ao, screenRect.x() + 2), pos.y() - sh.height());
     }
     path.lineTo(ml + rc, mb);
     path.arcTo(QRect(ml, mb - rc*2, rc*2, rc*2), -90, -90);
diff --git a/src/widgets/widgets/qcombobox.cpp b/src/widgets/widgets/qcombobox.cpp
index 042e702987..c42d951248 100644
--- a/src/widgets/widgets/qcombobox.cpp
+++ b/src/widgets/widgets/qcombobox.cpp
@@ -44,7 +44,6 @@
 #include <qpa/qplatformmenu.h>
 #include <qlineedit.h>
 #include <qapplication.h>
-#include <private/qdesktopwidget_p.h>
 #include <qlistview.h>
 #if QT_CONFIG(tableview)
 #include <qtableview.h>
diff --git a/src/widgets/widgets/qdatetimeedit.cpp b/src/widgets/widgets/qdatetimeedit.cpp
index 01f22b2dd6..d825676035 100644
--- a/src/widgets/widgets/qdatetimeedit.cpp
+++ b/src/widgets/widgets/qdatetimeedit.cpp
@@ -42,7 +42,6 @@
 #include <qabstractspinbox.h>
 #include <qapplication.h>
 #include <qdatetimeedit.h>
-#include <private/qdesktopwidget_p.h>
 #include <qdebug.h>
 #include <qevent.h>
 #include <qlineedit.h>
@@ -2598,28 +2597,31 @@ void QDateTimeEditPrivate::positionCalendarPopup()
     pos = q->mapToGlobal(pos);
     pos2 = q->mapToGlobal(pos2);
     QSize size = monthCalendar->sizeHint();
-    QRect screen = QDesktopWidgetPrivate::availableGeometry(pos);
+    QScreen *screen = QGuiApplication::screenAt(pos);
+    if (!screen)
+        screen = QGuiApplication::primaryScreen();
+    const QRect screenRect = screen->availableGeometry();
     //handle popup falling "off screen"
     if (q->layoutDirection() == Qt::RightToLeft) {
         pos.setX(pos.x()-size.width());
         pos2.setX(pos2.x()-size.width());
-        if (pos.x() < screen.left())
-            pos.setX(qMax(pos.x(), screen.left()));
-        else if (pos.x()+size.width() > screen.right())
-            pos.setX(qMax(pos.x()-size.width(), screen.right()-size.width()));
+        if (pos.x() < screenRect.left())
+            pos.setX(qMax(pos.x(), screenRect.left()));
+        else if (pos.x()+size.width() > screenRect.right())
+            pos.setX(qMax(pos.x()-size.width(), screenRect.right()-size.width()));
     } else {
-        if (pos.x()+size.width() > screen.right())
-            pos.setX(screen.right()-size.width());
-        pos.setX(qMax(pos.x(), screen.left()));
+        if (pos.x()+size.width() > screenRect.right())
+            pos.setX(screenRect.right()-size.width());
+        pos.setX(qMax(pos.x(), screenRect.left()));
     }
-    if (pos.y() + size.height() > screen.bottom())
+    if (pos.y() + size.height() > screenRect.bottom())
         pos.setY(pos2.y() - size.height());
-    else if (pos.y() < screen.top())
-        pos.setY(screen.top());
-    if (pos.y() < screen.top())
-        pos.setY(screen.top());
-    if (pos.y()+size.height() > screen.bottom())
-        pos.setY(screen.bottom()-size.height());
+    else if (pos.y() < screenRect.top())
+        pos.setY(screenRect.top());
+    if (pos.y() < screenRect.top())
+        pos.setY(screenRect.top());
+    if (pos.y()+size.height() > screenRect.bottom())
+        pos.setY(screenRect.bottom()-size.height());
     monthCalendar->move(pos);
 }
 
diff --git a/src/widgets/widgets/qdockarealayout.cpp b/src/widgets/widgets/qdockarealayout.cpp
index 022ee645cb..2654341505 100644
--- a/src/widgets/widgets/qdockarealayout.cpp
+++ b/src/widgets/widgets/qdockarealayout.cpp
@@ -44,7 +44,6 @@
 #include "QtWidgets/qtabbar.h"
 #endif
 #include "QtWidgets/qstyle.h"
-#include <private/qdesktopwidget_p.h>
 #include "QtWidgets/qapplication.h"
 #include "QtCore/qvariant.h"
 #include "qdockarealayout_p.h"
@@ -3019,19 +3018,20 @@ QSize QDockAreaLayout::minimumSize() const
  */
 QRect QDockAreaLayout::constrainedRect(QRect rect, QWidget* widget)
 {
-    QRect desktop;
+    QScreen *screen;
     if (QGuiApplication::primaryScreen()->virtualSiblings().size() > 1)
-        desktop = QDesktopWidgetPrivate::screenGeometry(rect.topLeft());
+        screen = QGuiApplication::screenAt(rect.topLeft());
     else
-        desktop = QWidgetPrivate::screenGeometry(widget);
-
-    if (desktop.isValid()) {
-        rect.setWidth(qMin(rect.width(), desktop.width()));
-        rect.setHeight(qMin(rect.height(), desktop.height()));
-        rect.moveLeft(qMax(rect.left(), desktop.left()));
-        rect.moveTop(qMax(rect.top(), desktop.top()));
-        rect.moveRight(qMin(rect.right(), desktop.right()));
-        rect.moveBottom(qMin(rect.bottom(), desktop.bottom()));
+        screen = widget->screen();
+
+    const QRect screenRect = screen->geometry();
+    if (screenRect.isValid()) {
+        rect.setWidth(qMin(rect.width(), screenRect.width()));
+        rect.setHeight(qMin(rect.height(), screenRect.height()));
+        rect.moveLeft(qMax(rect.left(), screenRect.left()));
+        rect.moveTop(qMax(rect.top(), screenRect.top()));
+        rect.moveRight(qMin(rect.right(), screenRect.right()));
+        rect.moveBottom(qMin(rect.bottom(), screenRect.bottom()));
     }
 
     return rect;
diff --git a/src/widgets/widgets/qeffects.cpp b/src/widgets/widgets/qeffects.cpp
index cdfad40760..0090f9b0b9 100644
--- a/src/widgets/widgets/qeffects.cpp
+++ b/src/widgets/widgets/qeffects.cpp
@@ -38,7 +38,9 @@
 ****************************************************************************/
 
 #include "qapplication.h"
+#include "qdebug.h"
 #include "qeffects_p.h"
+#include "qelapsedtimer.h"
 #include "qevent.h"
 #include "qimage.h"
 #include "qpainter.h"
@@ -46,10 +48,10 @@
 #include "qpixmap.h"
 #include "qpointer.h"
 #include "qtimer.h"
-#include "qelapsedtimer.h"
-#include "qdebug.h"
+#include "qwidget.h"
+#include "private/qwidget_p.h"
+#include "qwindow.h"
 
-#include <private/qdesktopwidget_p.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -98,8 +100,9 @@ static QAlphaWidget* q_blend = nullptr;
   Constructs a QAlphaWidget.
 */
 QAlphaWidget::QAlphaWidget(QWidget* w, Qt::WindowFlags f)
-    : QWidget(QApplication::desktop(w ? w->screen() : nullptr), f)
+    : QWidget(nullptr, f)
 {
+    QWidgetPrivate::get(this)->setScreen(w->screen());
 #ifndef Q_OS_WIN
     setEnabled(false);
 #endif
@@ -161,7 +164,7 @@ void QAlphaWidget::run(int time)
     resize(widget->size().width(), widget->size().height());
 
     frontImage = widget->grab().toImage();
-    backImage = QGuiApplication::primaryScreen()->grabWindow(QApplication::desktop()->winId(),
+    backImage = QGuiApplication::primaryScreen()->grabWindow(0,
                                 widget->geometry().x(), widget->geometry().y(),
                                 widget->geometry().width(), widget->geometry().height()).toImage();
 
@@ -379,8 +382,9 @@ static QRollEffect* q_roll = nullptr;
   Construct a QRollEffect widget.
 */
 QRollEffect::QRollEffect(QWidget* w, Qt::WindowFlags f, DirFlags orient)
-    : QWidget(QApplication::desktop(w ? w->screen() : nullptr), f), orientation(orient)
+    : QWidget(nullptr, f), orientation(orient)
 {
+    QWidgetPrivate::get(this)->setScreen(w->screen());
 #ifndef Q_OS_WIN
     setEnabled(false);
 #endif
diff --git a/src/widgets/widgets/qfontcombobox.cpp b/src/widgets/widgets/qfontcombobox.cpp
index a4ac34b51a..5f90853ec5 100644
--- a/src/widgets/widgets/qfontcombobox.cpp
+++ b/src/widgets/widgets/qfontcombobox.cpp
@@ -46,7 +46,6 @@
 #include <qevent.h>
 #include <qapplication.h>
 #include <private/qcombobox_p.h>
-#include <private/qdesktopwidget_p.h>
 #include <qdebug.h>
 
 QT_BEGIN_NAMESPACE
diff --git a/src/widgets/widgets/qmdiarea.cpp b/src/widgets/widgets/qmdiarea.cpp
index f2613bf5dd..c1913a3d09 100644
--- a/src/widgets/widgets/qmdiarea.cpp
+++ b/src/widgets/widgets/qmdiarea.cpp
@@ -165,7 +165,6 @@
 #include <QPainter>
 #include <QFontMetrics>
 #include <QStyleOption>
-#include <private/qdesktopwidget_p.h>
 #include <QDebug>
 #include <qmath.h>
 #if QT_CONFIG(menu)
diff --git a/src/widgets/widgets/qmenu.cpp b/src/widgets/widgets/qmenu.cpp
index 96945fe756..5edc480949 100644
--- a/src/widgets/widgets/qmenu.cpp
+++ b/src/widgets/widgets/qmenu.cpp
@@ -81,7 +81,6 @@
 #include <private/qaction_p.h>
 #include <private/qguiapplication_p.h>
 #include <qpa/qplatformtheme.h>
-#include <private/qdesktopwidget_p.h>
 #include <private/qstyle_p.h>
 
 QT_BEGIN_NAMESPACE
@@ -108,7 +107,7 @@ class QTornOffMenu : public QMenu
             Q_Q(QTornOffMenu);
             QSize size = menuSize;
             const QPoint p = (!initialized) ? causedMenu->pos() : q->pos();
-            QRect screen = popupGeometry(QDesktopWidgetPrivate::screenNumber(p));
+            const QRect screen = popupGeometry(QGuiApplication::screenAt(p));
             const int desktopFrame = q->style()->pixelMetric(QStyle::PM_MenuDesktopFrameWidth, nullptr, q);
             const int titleBarHeight = q->style()->pixelMetric(QStyle::PM_TitleBarHeight, nullptr, q);
             if (scroll && (size.height() > screen.height() - titleBarHeight || size.width() > screen.width())) {
@@ -319,19 +318,14 @@ inline bool QMenuPrivate::useFullScreenForPopup() const
     return !tornoff && QStylePrivate::useFullScreenForPopup();
 }
 
-QRect QMenuPrivate::popupGeometry() const
+QRect QMenuPrivate::popupGeometry(QScreen *screen) const
 {
     Q_Q(const QMenu);
-    return useFullScreenForPopup()
-        ? QWidgetPrivate::screenGeometry(q)
-        : QWidgetPrivate::availableScreenGeometry(q);
-}
-
-QRect QMenuPrivate::popupGeometry(int screen) const
-{
-    return useFullScreenForPopup()
-        ? QDesktopWidgetPrivate::screenGeometry(screen)
-        : QDesktopWidgetPrivate::availableGeometry(screen);
+    if (useFullScreenForPopup())
+        return screen ? screen->geometry()
+                      : QWidgetPrivate::screenGeometry(q);
+    return screen ? screen->availableGeometry()
+                  : QWidgetPrivate::availableScreenGeometry(q);
 }
 
 QList<QPointer<QWidget>> QMenuPrivate::calcCausedStack() const
@@ -2427,7 +2421,7 @@ void QMenuPrivate::popup(const QPoint &p, QAction *atAction, PositionFunction po
         screen = popupGeometry();
     else
 #endif
-    screen = popupGeometry(QDesktopWidgetPrivate::screenNumber(p));
+    screen = popupGeometry(QGuiApplication::screenAt(p));
     updateActionRects(screen);
 
     QPoint pos;
@@ -3668,7 +3662,7 @@ void QMenu::internalDelayedPopup()
         screen = d->popupGeometry();
     else
 #endif
-    screen = d->popupGeometry(QDesktopWidgetPrivate::screenNumber(pos()));
+    screen = d->popupGeometry(QGuiApplication::screenAt(pos()));
 
     int subMenuOffset = style()->pixelMetric(QStyle::PM_SubMenuOverlap, nullptr, this);
     const QRect actionRect(d->actionRect(d->currentAction));
diff --git a/src/widgets/widgets/qmenu_p.h b/src/widgets/widgets/qmenu_p.h
index 4814fcaad9..ffe956d007 100644
--- a/src/widgets/widgets/qmenu_p.h
+++ b/src/widgets/widgets/qmenu_p.h
@@ -352,8 +352,7 @@ public:
     mutable QHash<QAction *, QWidget *> widgetItems;
     void updateActionRects() const;
     void updateActionRects(const QRect &screen) const;
-    QRect popupGeometry() const;
-    QRect popupGeometry(int screen) const;
+    QRect popupGeometry(QScreen *screen = nullptr) const;
     bool useFullScreenForPopup() const;
     int getLastVisibleAction() const;
     void popup(const QPoint &p, QAction *atAction, PositionFunction positionFunction = {});
diff --git a/src/widgets/widgets/qmenubar.cpp b/src/widgets/widgets/qmenubar.cpp
index 10c44e4203..5fd84f7f3b 100644
--- a/src/widgets/widgets/qmenubar.cpp
+++ b/src/widgets/widgets/qmenubar.cpp
@@ -63,7 +63,6 @@
 #include <qpa/qplatformtheme.h>
 #include "private/qguiapplication_p.h"
 #include "qpa/qplatformintegration.h"
-#include <private/qdesktopwidget_p.h>
 
 #include "qmenu_p.h"
 #include "qmenubar_p.h"
diff --git a/src/widgets/widgets/qpushbutton.cpp b/src/widgets/widgets/qpushbutton.cpp
index 8657eb4174..4faa8c7f67 100644
--- a/src/widgets/widgets/qpushbutton.cpp
+++ b/src/widgets/widgets/qpushbutton.cpp
@@ -39,7 +39,6 @@
 
 #include "qapplication.h"
 #include "qbitmap.h"
-#include <private/qdesktopwidget_p.h>
 #if QT_CONFIG(dialog)
 #include <private/qdialog_p.h>
 #endif
diff --git a/src/widgets/widgets/qsizegrip.cpp b/src/widgets/widgets/qsizegrip.cpp
index 02d9b4f3f1..946839c373 100644
--- a/src/widgets/widgets/qsizegrip.cpp
+++ b/src/widgets/widgets/qsizegrip.cpp
@@ -50,7 +50,6 @@
 #include "qdebug.h"
 
 #include <private/qwidget_p.h>
-#include <private/qdesktopwidget_p.h>
 #include <QtWidgets/qabstractscrollarea.h>
 
 QT_BEGIN_NAMESPACE
diff --git a/src/widgets/widgets/qsplashscreen.cpp b/src/widgets/widgets/qsplashscreen.cpp
index 1f1c71dcb8..2c2d1922be 100644
--- a/src/widgets/widgets/qsplashscreen.cpp
+++ b/src/widgets/widgets/qsplashscreen.cpp
@@ -40,7 +40,6 @@
 #include "qsplashscreen.h"
 
 #include "qapplication.h"
-#include <private/qdesktopwidget_p.h>
 #include "qpainter.h"
 #include "qpixmap.h"
 #include "qtextdocument.h"
@@ -69,10 +68,6 @@ public:
     int currAlign;
 
     inline QSplashScreenPrivate();
-
-    void setPixmap(const QPixmap &p, const QScreen *screen = nullptr);
-
-    static const QScreen *screenFor(const QWidget *w);
 };
 
 /*!
@@ -153,7 +148,9 @@ QSplashScreen::QSplashScreen(const QPixmap &pixmap, Qt::WindowFlags f)
 QSplashScreen::QSplashScreen(QScreen *screen, const QPixmap &pixmap, Qt::WindowFlags f)
     : QWidget(*(new QSplashScreenPrivate()), nullptr, Qt::SplashScreen | Qt::FramelessWindowHint | f)
 {
-    d_func()->setPixmap(pixmap, screen);
+    Q_D(QSplashScreen);
+    d->setScreen(screen);
+    setPixmap(pixmap);
 }
 
 /*!
@@ -283,52 +280,16 @@ void QSplashScreen::finish(QWidget *mainWin)
 */
 void QSplashScreen::setPixmap(const QPixmap &pixmap)
 {
-    d_func()->setPixmap(pixmap, QSplashScreenPrivate::screenFor(this));
-}
-
-// In setPixmap(), resize and try to position on a screen according to:
-// 1) If the screen for the given widget is available, use that
-// 2) If a QDesktopScreenWidget is found in the parent hierarchy, use that (see docs on
-//    QSplashScreen(QWidget *, QPixmap).
-// 3) If a widget with associated QWindow is found, use that
-// 4) When nothing can be found, try to center it over the cursor
-
-const QScreen *QSplashScreenPrivate::screenFor(const QWidget *w)
-{
-    if (w && w->screen())
-        return w->screen();
-
-    for (const QWidget *p = w; p !=nullptr ; p = p->parentWidget()) {
-        if (auto dsw = qobject_cast<const QDesktopScreenWidget *>(p))
-            return dsw->screen();
-        if (QWindow *window = p->windowHandle())
-            return window->screen();
-    }
-
-#if QT_CONFIG(cursor)
-    // Note: We could rely on QPlatformWindow::initialGeometry() to center it
-    // over the cursor, but not all platforms (namely Android) use that.
-    if (QGuiApplication::screens().size() > 1) {
-        if (auto screenAtCursor = QGuiApplication::screenAt(QCursor::pos()))
-            return screenAtCursor;
-    }
-#endif // cursor
-    return QGuiApplication::primaryScreen();
-}
-
-void QSplashScreenPrivate::setPixmap(const QPixmap &p, const QScreen *screen)
-{
-    Q_Q(QSplashScreen);
+    Q_D(QSplashScreen);
+    d->pixmap = pixmap;
+    setAttribute(Qt::WA_TranslucentBackground, pixmap.hasAlpha());
 
-    pixmap = p;
-    q->setAttribute(Qt::WA_TranslucentBackground, pixmap.hasAlpha());
+    const QRect r(QPoint(), pixmap.size() / pixmap.devicePixelRatio());
+    resize(r.size());
 
-    QRect r(QPoint(), pixmap.size() / pixmap.devicePixelRatio());
-    q->resize(r.size());
-    if (screen)
-        q->move(screen->geometry().center() - r.center());
-    if (q->isVisible())
-        q->repaint();
+    move(screen()->geometry().center() - r.center());
+    if (isVisible())
+        repaint();
 }
 
 /*!
diff --git a/src/widgets/widgets/qtabwidget.cpp b/src/widgets/widgets/qtabwidget.cpp
index e054156995..710d5a42a7 100644
--- a/src/widgets/widgets/qtabwidget.cpp
+++ b/src/widgets/widgets/qtabwidget.cpp
@@ -44,7 +44,6 @@
 #include "private/qtabbar_p.h"
 #include "qapplication.h"
 #include "qbitmap.h"
-#include <private/qdesktopwidget_p.h>
 #include "qevent.h"
 #include "qlayout.h"
 #include "qstackedwidget.h"
diff --git a/src/widgets/widgets/qtoolbutton.cpp b/src/widgets/widgets/qtoolbutton.cpp
index 0b090d2bac..5a394cfda8 100644
--- a/src/widgets/widgets/qtoolbutton.cpp
+++ b/src/widgets/widgets/qtoolbutton.cpp
@@ -40,7 +40,6 @@
 #include "qtoolbutton.h"
 
 #include <qapplication.h>
-#include <private/qdesktopwidget_p.h>
 #include <qdrawutil.h>
 #include <qevent.h>
 #include <qicon.h>
@@ -728,7 +727,7 @@ static QPoint positionMenu(const QToolButton *q, bool horizontal,
 {
     QPoint p;
     const QRect rect = q->rect(); // Find screen via point in case of QGraphicsProxyWidget.
-    QRect screen = QDesktopWidgetPrivate::availableGeometry(q->mapToGlobal(rect.center()));
+    const QRect screen = QWidgetPrivate::availableScreenGeometry(q);
     if (horizontal) {
         if (q->isRightToLeft()) {
             if (q->mapToGlobal(QPoint(0, rect.bottom())).y() + sh.height() <= screen.bottom()) {
diff --git a/src/widgets/widgets/qwidgetresizehandler.cpp b/src/widgets/widgets/qwidgetresizehandler.cpp
index 4f6541f509..0cf9457a57 100644
--- a/src/widgets/widgets/qwidgetresizehandler.cpp
+++ b/src/widgets/widgets/qwidgetresizehandler.cpp
@@ -41,7 +41,7 @@
 
 #include "qframe.h"
 #include "qapplication.h"
-#include <private/qdesktopwidget_p.h>
+#include "private/qwidget_p.h"
 #include "qcursor.h"
 #if QT_CONFIG(sizegrip)
 #include "qsizegrip.h"