Phase 2 of removing QDesktopWidget

Remove QDestopWidget public header, simplify the implementation that
maintains a Qt::Desktop type QWidget for each QScreen, and turn
QWidget's initial target screen into a QScreen pointer.

QApplication::desktop() now takes an optional QScreen pointer, and
returns a QWidget pointer, so that applications and widgets can get
access to the root widget for a specific screen without having to
resort to private APIs.

QDesktopWidgetPrivate implementations to look up a screen for an index,
widget, or point are now all inline functions that thinly wrap
QGuiApplication::screens/screenAt calls. We should consider adding those
as convenience APIs to QScreen instead.

Note that QWidget::screen is assumed to return a valid pointer; there is
code that handles the case that it returns nullptr (but also code that
trusts that it never is nullptr), so this needs to be defined, verified
with tests, and asserted. We can then simplify the code further.

Change-Id: Ifc89be65a0dce265b6729feaf54121c35137cb94
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

10 files changed, 3 insertions, 13 deletions

diff --git a/tests/auto/widgets/dialogs/qdialog/tst_qdialog.cpp b/tests/auto/widgets/dialogs/qdialog/tst_qdialog.cpp
index d469b0f9bd..91d0c07efd 100644
--- a/tests/auto/widgets/dialogs/qdialog/tst_qdialog.cpp
+++ b/tests/auto/widgets/dialogs/qdialog/tst_qdialog.cpp
@@ -37,7 +37,6 @@
 #include <qstyle.h>
 #include <QVBoxLayout>
 #include <QSizeGrip>
-#include <QDesktopWidget>
 #include <QGraphicsProxyWidget>
 #include <QGraphicsView>
 #include <QWindow>
diff --git a/tests/auto/widgets/effects/qgraphicseffect/tst_qgraphicseffect.cpp b/tests/auto/widgets/effects/qgraphicseffect/tst_qgraphicseffect.cpp
index 19288d07a7..38181c8af0 100644
--- a/tests/auto/widgets/effects/qgraphicseffect/tst_qgraphicseffect.cpp
+++ b/tests/auto/widgets/effects/qgraphicseffect/tst_qgraphicseffect.cpp
@@ -28,7 +28,6 @@
 
 
 #include <QtTest/QtTestWidgets>
-#include <QtWidgets/qdesktopwidget.h>
 #include <QtWidgets/qgraphicseffect.h>
 #include <QtWidgets/qgraphicsview.h>
 #include <QtWidgets/qgraphicsscene.h>
diff --git a/tests/auto/widgets/graphicsview/qgraphicsitem/tst_qgraphicsitem.cpp b/tests/auto/widgets/graphicsview/qgraphicsitem/tst_qgraphicsitem.cpp
index e7a79d017b..9ae127dbe0 100644
--- a/tests/auto/widgets/graphicsview/qgraphicsitem/tst_qgraphicsitem.cpp
+++ b/tests/auto/widgets/graphicsview/qgraphicsitem/tst_qgraphicsitem.cpp
@@ -38,7 +38,6 @@
 #include <QAbstractTextDocumentLayout>
 #include <QBitmap>
 #include <QCursor>
-#include <QDesktopWidget>
 #include <QScreen>
 #include <QLabel>
 #include <QDial>
diff --git a/tests/auto/widgets/itemviews/qheaderview/tst_qheaderview.cpp b/tests/auto/widgets/itemviews/qheaderview/tst_qheaderview.cpp
index 1553b6e982..afb1b18af0 100644
--- a/tests/auto/widgets/itemviews/qheaderview/tst_qheaderview.cpp
+++ b/tests/auto/widgets/itemviews/qheaderview/tst_qheaderview.cpp
@@ -27,7 +27,6 @@
 **
 ****************************************************************************/
 
-#include <QDesktopWidget>
 #include <QHeaderView>
 #include <QProxyStyle>
 #include <QSignalSpy>
diff --git a/tests/auto/widgets/itemviews/qtreeview/tst_qtreeview.cpp b/tests/auto/widgets/itemviews/qtreeview/tst_qtreeview.cpp
index f85b885b34..531d1e823a 100644
--- a/tests/auto/widgets/itemviews/qtreeview/tst_qtreeview.cpp
+++ b/tests/auto/widgets/itemviews/qtreeview/tst_qtreeview.cpp
@@ -28,7 +28,6 @@
 
 #include "../../../../shared/fakedirmodel.h"
 
-#include <QDesktopWidget>
 #include <QHeaderView>
 #include <QLabel>
 #include <QLineEdit>
diff --git a/tests/auto/widgets/kernel/qdesktopwidget/.gitignore b/tests/auto/widgets/kernel/qdesktopwidget/.gitignore
deleted file mode 100644
index d6f7cc7ca9..0000000000
--- a/tests/auto/widgets/kernel/qdesktopwidget/.gitignore
+++ /dev/null
@@ -1 +0,0 @@
-tst_qdesktopwidget
diff --git a/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp b/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp
index 873d0460ff..b05d6cd96e 100644
--- a/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp
+++ b/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp
@@ -44,7 +44,6 @@
 #include <qstyle.h>
 #include <qwidget.h>
 #include <qstylefactory.h>
-#include <qdesktopwidget.h>
 #include <private/qwidget_p.h>
 #include <private/qwidgetrepaintmanager_p.h>
 #include <private/qapplication_p.h>
@@ -9170,7 +9169,7 @@ void tst_QWidget::translucentWidget()
     QPixmap widgetSnapshot;
 
 #ifdef Q_OS_WIN
-    QWidget *desktopWidget = QApplication::desktop()->screen(0);
+    QWidget *desktopWidget = QApplication::desktop();
     widgetSnapshot = grabWindow(desktopWidget->windowHandle(), labelPos.x(), labelPos.y(), label.width(), label.height());
 #else
     widgetSnapshot = label.grab(QRect(QPoint(0, 0), label.size()));
diff --git a/tests/auto/widgets/widgets/qmdiarea/tst_qmdiarea.cpp b/tests/auto/widgets/widgets/qmdiarea/tst_qmdiarea.cpp
index f8a91e6ec6..7899f1f523 100644
--- a/tests/auto/widgets/widgets/qmdiarea/tst_qmdiarea.cpp
+++ b/tests/auto/widgets/widgets/qmdiarea/tst_qmdiarea.cpp
@@ -40,7 +40,6 @@
 #include <QStyleOption>
 #include <QVBoxLayout>
 #include <QLineEdit>
-#include <QDesktopWidget>
 #include <QDockWidget>
 #include <QScrollBar>
 #include <QTextEdit>
diff --git a/tests/auto/widgets/widgets/qmenu/tst_qmenu.cpp b/tests/auto/widgets/widgets/qmenu/tst_qmenu.cpp
index 8ce0ea2184..783476cf67 100644
--- a/tests/auto/widgets/widgets/qmenu/tst_qmenu.cpp
+++ b/tests/auto/widgets/widgets/qmenu/tst_qmenu.cpp
@@ -38,7 +38,6 @@
 #include <QStatusBar>
 #include <QListWidget>
 #include <QWidgetAction>
-#include <QDesktopWidget>
 #include <QScreen>
 #include <QSpinBox>
 #include <qdialog.h>
diff --git a/tests/auto/widgets/widgets/qopenglwidget/tst_qopenglwidget.cpp b/tests/auto/widgets/widgets/qopenglwidget/tst_qopenglwidget.cpp
index cb4fc201f6..ccd8d0ec05 100644
--- a/tests/auto/widgets/widgets/qopenglwidget/tst_qopenglwidget.cpp
+++ b/tests/auto/widgets/widgets/qopenglwidget/tst_qopenglwidget.cpp
@@ -31,7 +31,6 @@
 #include <QtGui/QPainter>
 #include <QtGui/QScreen>
 #include <QtGui/QStaticText>
-#include <QtWidgets/QDesktopWidget>
 #include <QtWidgets/QGraphicsView>
 #include <QtWidgets/QGraphicsScene>
 #include <QtWidgets/QGraphicsRectItem>
@@ -504,8 +503,8 @@ static QPixmap grabWidgetWithoutRepaint(const QWidget *widget, QRect clipArea)
     // because GDI functions can't grab OpenGL layer content.
     // Instead the whole screen should be captured, with an adjusted clip area, which contains
     // the final composited content.
-    QDesktopWidget *desktopWidget = QApplication::desktop();
-    const QWidget *mainScreenWidget = desktopWidget->screen();
+    QWidget *desktopWidget = QApplication::desktop(QGuiApplication::primaryScreen());
+    const QWidget *mainScreenWidget = desktopWidget;
     targetWidget = mainScreenWidget;
     clipArea = QRect(widget->mapToGlobal(clipArea.topLeft()),
                      widget->mapToGlobal(clipArea.bottomRight()));