From 8fcc92e38a7ce509ba49c8c0cfeb3ad9f402f4e0 Mon Sep 17 00:00:00 2001
From: Volker Hilsheimer <volker.hilsheimer@qt.io>
Date: Wed, 30 Nov 2022 16:17:18 +0100
Subject: [PATCH] Deliver tablet events to the toplevel widget if there is no
 child

QWidgetWindow dispatched only tablet presses to the toplevel widget if
no child was found at the position; other events, such as hover events,
were discarded. The tabletTracking test case even documented that
shortcoming in a comment.

Fix that by falling back to the toplevel widget for any event. As
before, only press events initialize the tablet grabbing target widget.

Remove the now unneeded parent widget from the test case, and move the
test class into the only test function that uses it.

Amends ea615b421b76668332a3029ad31fa725b5bb9e58 and
8fd6cef3724b2d676c5f6ae235956192d85eac39.

Fixes: QTBUG-108747
Change-Id: I79050f1e063931e439945f64b50712dcc1ecb18c
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>
(cherry picked from commit 7956d9e06032e5488d57cf1dc1c9aae0e7172a20)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
---
 src/widgets/kernel/qwidgetwindow.cpp          |  7 +-
 .../widgets/kernel/qwidget/tst_qwidget.cpp    | 88 +++++++++----------
 2 files changed, 44 insertions(+), 51 deletions(-)

diff --git a/src/widgets/kernel/qwidgetwindow.cpp b/src/widgets/kernel/qwidgetwindow.cpp
index 61dfa5b2f13..626994fc2da 100644
--- a/src/widgets/kernel/qwidgetwindow.cpp
+++ b/src/widgets/kernel/qwidgetwindow.cpp
@@ -1051,11 +1051,10 @@ void QWidgetWindow::handleTabletEvent(QTabletEvent *event)
 
     if (!widget) {
         widget = m_widget->childAt(event->position().toPoint());
-        if (event->type() == QEvent::TabletPress) {
-            if (!widget)
-                widget = m_widget;
+        if (!widget)
+            widget = m_widget;
+        if (event->type() == QEvent::TabletPress)
             qt_tablet_target = widget;
-        }
     }
 
     if (widget) {
diff --git a/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp b/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp
index 3d275a8e593..9f0cdb9d2d0 100644
--- a/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp
+++ b/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp
@@ -12480,60 +12480,54 @@ void tst_QWidget::testForOutsideWSRangeFlag()
     }
 }
 
-class TabletWidget : public QWidget
-{
-public:
-    TabletWidget(QWidget *parent) : QWidget(parent) { }
-
-    int tabletEventCount = 0;
-    int pressEventCount = 0;
-    int moveEventCount = 0;
-    int releaseEventCount = 0;
-    int trackingChangeEventCount = 0;
-    qint64 uid = -1;
-
-protected:
-    void tabletEvent(QTabletEvent *event) override {
-        ++tabletEventCount;
-        uid = event->pointingDevice()->uniqueId().numericId();
-        switch (event->type()) {
-        case QEvent::TabletMove:
-            ++moveEventCount;
-            break;
-        case QEvent::TabletPress:
-            ++pressEventCount;
-            break;
-        case QEvent::TabletRelease:
-            ++releaseEventCount;
-            break;
-        default:
-            break;
-        }
-    }
-
-    bool event(QEvent *ev) override {
-        if (ev->type() == QEvent::TabletTrackingChange)
-            ++trackingChangeEventCount;
-        return QWidget::event(ev);
-    }
-};
-
 void tst_QWidget::tabletTracking()
 {
-    QWidget parent;
-    parent.setWindowTitle(QLatin1String(QTest::currentTestFunction()));
-    parent.resize(200,200);
-    // QWidgetWindow::handleTabletEvent doesn't deliver tablet events to the window's widget, only to a child.
-    // So it doesn't do any good to show a TabletWidget directly: it needs a parent.
-    TabletWidget widget(&parent);
+    class TabletWidget : public QWidget
+    {
+    public:
+        using QWidget::QWidget;
+
+        int tabletEventCount = 0;
+        int pressEventCount = 0;
+        int moveEventCount = 0;
+        int releaseEventCount = 0;
+        int trackingChangeEventCount = 0;
+        qint64 uid = -1;
+
+    protected:
+        void tabletEvent(QTabletEvent *event) override {
+            ++tabletEventCount;
+            uid = event->pointingDevice()->uniqueId().numericId();
+            switch (event->type()) {
+            case QEvent::TabletMove:
+                ++moveEventCount;
+                break;
+            case QEvent::TabletPress:
+                ++pressEventCount;
+                break;
+            case QEvent::TabletRelease:
+                ++releaseEventCount;
+                break;
+            default:
+                break;
+            }
+        }
+
+        bool event(QEvent *ev) override {
+            if (ev->type() == QEvent::TabletTrackingChange)
+                ++trackingChangeEventCount;
+            return QWidget::event(ev);
+        }
+    } widget;
+    widget.setWindowTitle(QLatin1String(QTest::currentTestFunction()));
     widget.resize(200,200);
-    parent.showNormal();
-    QVERIFY(QTest::qWaitForWindowExposed(&parent));
+    widget.showNormal();
+    QVERIFY(QTest::qWaitForWindowExposed(&widget));
     widget.setAttribute(Qt::WA_TabletTracking);
     QTRY_COMPARE(widget.trackingChangeEventCount, 1);
     QVERIFY(widget.hasTabletTracking());
 
-    QWindow *window = parent.windowHandle();
+    QWindow *window = widget.windowHandle();
     QPointF local(10, 10);
     QPointF global = window->mapToGlobal(local.toPoint());
     QPointF deviceLocal = QHighDpi::toNativeLocalPosition(local, window);