Workaround for EGLFS not supporting per window mouse cursor shape

When hovering over the floating window edges our mouse cursor
changes to resize shape, but when leaving and entering the main window
the mouse cursor wasn't unset.

Workaround by using a global event filter and detecting the leave.

Not using QEvent::Leave as we still allow for some margin outside
the floating window to count as a resize cursor

src/private/FloatingWindow.cpp

@@ -230,7 +230,13 @@ void FloatingWindow::maybeCreateResizeHandler()
 {
     if (!KDDockWidgets::usesNativeDraggingAndResizing()) {
         setFlag(Qt::FramelessWindowHint, true);
-        setWidgetResizeHandler(new WidgetResizeHandler(WidgetResizeHandler::EventFilterMode::Local, WidgetResizeHandler::WindowMode::TopLevel, this));
+        // EGLFS can't have different mouse cursors per window, needs global filter hack to unset when cursor leaves
+        const auto filterMode = isEGLFS() ? WidgetResizeHandler::EventFilterMode::Global
+                                          : WidgetResizeHandler::EventFilterMode::Local;
+
+        setWidgetResizeHandler(new WidgetResizeHandler(filterMode,
+                                                       WidgetResizeHandler::WindowMode::TopLevel,
+                                                       this));
     }
 }
 

src/private/WidgetResizeHandler.cpp

@@ -88,10 +88,31 @@ bool WidgetResizeHandler::eventFilter(QObject *o, QEvent *e)
     if (!widget)
         return false;
 
-    if (m_isTopLevelWindowResizer) {
+    auto me = mouseEvent(e);
-        if (!widget->isTopLevel() || o != mTarget)
+    if (!me)
         return false;
+
+    if (m_isTopLevelWindowResizer) {
+        // Case #1.0: Resizing FloatingWindow
+
+        if (!widget->isTopLevel() || o != mTarget) {
+            if (m_usesGlobalEventFilter) {
+                // Case #1.1: FloatingWindows on EGLFS
+                // EGLFS doesn't support storing mouse cursor shape per window, so we need to use global filter
+                // do detect mouse leaving the window
+                if (!m_resizingInProgress) {
+                    const QPoint globalPos = Qt5Qt6Compat::eventGlobalPos(me);
+                    updateCursor(cursorPosition(globalPos));
+                }
+            }
+
+            // Case #1.2: FloatingWindows on all other platforms
+            // Not needed to mess with the cursor, it gets set when moving over another window.
+            return false;
+        }
     } else if (isMDI()) {
+        // Case #2: Resizing an embedded MDI "Window"
+
         // Each Frame has a WidgetResizeHandler instance.
         // mTarget is the Frame we want to resize.
         // but 'o' might not be mTarget, because we're using a global event filter.