Wide QMenu: fix size and position

This patch fixes 2 issues related to wide menus:
1) Menu took on full screen height when menu width was larger than
screen width;
2) On a multi-display system wide menu might appear on wrong monitor
(not the one where show event was triggered).

The idea is we limit parent menu and all its submenus within the screen
where it was opened.

Note that this patch fixes only geometry-related issues and there are
also some style flaws which need to be addressed (for example, currently
the text does not elide if it doesn’t fit to the menu’s width).

Task-number: QTBUG-56917
Change-Id: I7e9ff4a48bf03060d76e34d33a13ad6cc890c133
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@qt.io>

2 files changed, 16 insertions, 30 deletions

diff --git a/src/widgets/widgets/qmenu.cpp b/src/widgets/widgets/qmenu.cpp
index 2917083415..16f8734d7b 100644
--- a/src/widgets/widgets/qmenu.cpp
+++ b/src/widgets/widgets/qmenu.cpp
@@ -401,17 +401,6 @@ void QMenuPrivate::updateActionRects(const QRect &screen) const
     itemsDirty = 0;
 }
 
-QSize QMenuPrivate::adjustMenuSizeForScreen(const QRect &screen)
-{
-    Q_Q(QMenu);
-    QSize ret = screen.size();
-    itemsDirty = true;
-    updateActionRects(screen);
-    const int fw = q->style()->pixelMetric(QStyle::PM_MenuPanelWidth, 0, q);
-    ret.setWidth(actionRects.at(getLastVisibleAction()).right() + fw);
-    return ret;
-}
-
 int QMenuPrivate::getLastVisibleAction() const
 {
     //let's try to get the last visible action
@@ -2265,7 +2254,8 @@ void QMenu::popup(const QPoint &p, QAction *atAction)
     else
         pos = p;
 
-    QSize size = sizeHint();
+    const QSize menuSizeHint(sizeHint());
+    QSize size = menuSizeHint;
     QRect screen;
 #ifndef QT_NO_GRAPHICSVIEW
     bool isEmbedded = !bypassGraphicsProxyWidget(this) && d->nearestGraphicsProxyWidget(this);
@@ -2278,13 +2268,11 @@ void QMenu::popup(const QPoint &p, QAction *atAction)
     bool adjustToDesktop = !window()->testAttribute(Qt::WA_DontShowOnScreen);
 
     // if the screens have very different geometries and the menu is too big, we have to recalculate
-    if (size.height() > screen.height() || size.width() > screen.width()) {
-        size = d->adjustMenuSizeForScreen(screen);
-        adjustToDesktop = true;
-    }
-    // Layout is not right, we might be able to save horizontal space
-    if (d->ncols >1 && size.height() < screen.height()) {
-        size = d->adjustMenuSizeForScreen(screen);
+    if ((size.height() > screen.height() || size.width() > screen.width()) ||
+        // Layout is not right, we might be able to save horizontal space
+        (d->ncols >1 && size.height() < screen.height())) {
+        size.setWidth(qMin(menuSizeHint.width(), screen.width() - desktopFrame * 2));
+        size.setHeight(qMin(menuSizeHint.height(), screen.height() - desktopFrame * 2));
         adjustToDesktop = true;
     }
 
@@ -2337,7 +2325,6 @@ void QMenu::popup(const QPoint &p, QAction *atAction)
     d->mousePopupPos = mouse;
     const bool snapToMouse = !d->causedPopup.widget && (QRect(p.x() - 3, p.y() - 3, 6, 6).contains(mouse));
 
-    const QSize menuSize(sizeHint());
     if (adjustToDesktop) {
         // handle popup falling "off screen"
         if (isRightToLeft()) {
@@ -2371,7 +2358,7 @@ void QMenu::popup(const QPoint &p, QAction *atAction)
 
         if (pos.y() < screen.top() + desktopFrame)
             pos.setY(screen.top() + desktopFrame);
-        if (pos.y() + menuSize.height() - 1 > screen.bottom() - desktopFrame) {
+        if (pos.y() + menuSizeHint.height() - 1 > screen.bottom() - desktopFrame) {
             if (d->scroll) {
                 d->scroll->scrollFlags |= uint(QMenuPrivate::QMenuScroller::ScrollDown);
                 int y = qMax(screen.y(),pos.y());
@@ -2384,29 +2371,29 @@ void QMenu::popup(const QPoint &p, QAction *atAction)
     }
     const int subMenuOffset = style()->pixelMetric(QStyle::PM_SubMenuOverlap, 0, this);
     QMenu *caused = qobject_cast<QMenu*>(d_func()->causedPopup.widget);
-    if (caused && caused->geometry().width() + menuSize.width() + subMenuOffset < screen.width()) {
+    if (caused && caused->geometry().width() + menuSizeHint.width() + subMenuOffset < screen.width()) {
         QRect parentActionRect(caused->d_func()->actionRect(caused->d_func()->currentAction));
         const QPoint actionTopLeft = caused->mapToGlobal(parentActionRect.topLeft());
         parentActionRect.moveTopLeft(actionTopLeft);
         if (isRightToLeft()) {
-            if ((pos.x() + menuSize.width() > parentActionRect.left() - subMenuOffset)
+            if ((pos.x() + menuSizeHint.width() > parentActionRect.left() - subMenuOffset)
                 && (pos.x() < parentActionRect.right()))
             {
-                pos.rx() = parentActionRect.left() - menuSize.width();
+                pos.rx() = parentActionRect.left() - menuSizeHint.width();
                 if (pos.x() < screen.x())
                     pos.rx() = parentActionRect.right();
-                if (pos.x() + menuSize.width() > screen.x() + screen.width())
+                if (pos.x() + menuSizeHint.width() > screen.x() + screen.width())
                     pos.rx() = screen.x();
             }
         } else {
             if ((pos.x() < parentActionRect.right() + subMenuOffset)
-                && (pos.x() + menuSize.width() > parentActionRect.left()))
+                && (pos.x() + menuSizeHint.width() > parentActionRect.left()))
             {
                 pos.rx() = parentActionRect.right();
-                if (pos.x() + menuSize.width() > screen.x() + screen.width())
-                    pos.rx() = parentActionRect.left() - menuSize.width();
+                if (pos.x() + menuSizeHint.width() > screen.x() + screen.width())
+                    pos.rx() = parentActionRect.left() - menuSizeHint.width();
                 if (pos.x() < screen.x())
-                    pos.rx() = screen.x() + screen.width() - menuSize.width();
+                    pos.rx() = screen.x() + screen.width() - menuSizeHint.width();
             }
         }
     }
diff --git a/src/widgets/widgets/qmenu_p.h b/src/widgets/widgets/qmenu_p.h
index 64291e842f..898fa3161b 100644
--- a/src/widgets/widgets/qmenu_p.h
+++ b/src/widgets/widgets/qmenu_p.h
@@ -311,7 +311,6 @@ public:
     mutable uint ncols : 4; //4 bits is probably plenty
     uint collapsibleSeparators : 1;
     uint toolTipsVisible : 1;
-    QSize adjustMenuSizeForScreen(const QRect & screen);
     int getLastVisibleAction() const;
 
     bool activationRecursionGuard;