widgets: Pass popup semantic information to Wayland

On Wayland applications do not know their own window positions, this
means that popups cannot stay on screen by themselves. When a window
tries to go offscreen the way the window is adjusted is
context-specific:
- The first menu will be kept on screen by moving the x position until
it all fits.
 - A submenu is too close to the screen edge, the menu will open on the
opposite side of the parent menu to avoid obscuring it.
 - A combo box drop downs will vertically flip to the other side of the
originating combobox.

The Wayland API requires the application to provide semantic hints about
the area in which the popup should be placed, along with hints about in
which direction we should try to place the popup and how to handle being
constrained.

At a QPA level we don't know the location of individual widgets so this
needs forwarding explicitly. Rather than exposing all possible
positioning information, it is inferred from the window type at a QPA
level, this required extending windowType to have more explicit values.

Ideally this needs to be application-facing API as there are third-party
comboboxes, but for now it is private with Qt's default controls opting
into it.

Task-number: QTBUG-99618
Task-number: QTBUG-124810
Fixes: QTBUG-135883
Change-Id: I49a2f18d1bfe1b755f259627722e076d58c13e8f
Reviewed-by: David Redondo <[email protected]>

1 files changed, 13 insertions, 0 deletions

diff --git a/src/widgets/kernel/qtooltip.cpp b/src/widgets/kernel/qtooltip.cpp
index 9e6aaf4b95f..d989feb7f91 100644
--- a/src/widgets/kernel/qtooltip.cpp
+++ b/src/widgets/kernel/qtooltip.cpp
@@ -20,6 +20,8 @@
 #if QT_CONFIG(style_stylesheet)
 #include <private/qstylesheetstyle_p.h>
 #endif
+#include <qpa/qplatformwindow.h>
+#include <qpa/qplatformwindow_p.h>
 
 #include <qlabel.h>
 #include <QtWidgets/private/qlabel_p.h>
@@ -386,6 +388,17 @@ void QTipLabel::placeTip(const QPoint &pos, QWidget *w)
 
         p += offset;
 
+#if QT_CONFIG(wayland)
+        create();
+        if (auto waylandWindow = dynamic_cast<QNativeInterface::Private::QWaylandWindow*>(windowHandle()->handle())) {
+            // based on the existing code below, by default position at 'p' stored at the bottom right of our rect
+            // then  flip to the other arbitrary 4x24 space if constrained
+            const QRect controlGeometry(QRect(p.x() - 4, p.y() - 24, 4, 24));
+            waylandWindow->setParentControlGeometry(controlGeometry);
+            waylandWindow->setExtendedWindowType(QNativeInterface::Private::QWaylandWindow::ToolTip);
+        }
+#endif
+
         QRect screenRect = screen->geometry();
         if (p.x() + this->width() > screenRect.x() + screenRect.width())
             p.rx() -= 4 + this->width();