Add way to override when to show context menu

Add Qt::ContextMenuTrigger enum used with
QStyleHints::setContextMenuTrigger() to override default platform
behavior when to trigger context menu event.
The default is to show context menu on mouse press on
UNIX systems and on mouse release on Windows.

Give developer a possibility to override platform default behavior
to make cross platform application that behaves the same way on all
platforms

Task-number: QTBUG-93486
Change-Id: Ic832d3d8a7c355a8adb46868fff9cfd19988cf3c
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

6 files changed, 54 insertions, 5 deletions

diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
index c97374e975..f2b914f203 100644
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -3447,6 +3447,15 @@ void QGuiApplicationPrivate::updatePalette()
     }
 }
 
+QEvent::Type QGuiApplicationPrivate::contextMenuEventType()
+{
+    switch (QGuiApplication::styleHints()->contextMenuTrigger()) {
+    case Qt::ContextMenuTrigger::Press: return QEvent::MouseButtonPress;
+    case Qt::ContextMenuTrigger::Release: return QEvent::MouseButtonRelease;
+    }
+    return QEvent::None;
+}
+
 void QGuiApplicationPrivate::clearPalette()
 {
     delete app_pal;
diff --git a/src/gui/kernel/qguiapplication_p.h b/src/gui/kernel/qguiapplication_p.h
index cca79534fc..39c490c581 100644
--- a/src/gui/kernel/qguiapplication_p.h
+++ b/src/gui/kernel/qguiapplication_p.h
@@ -323,6 +323,8 @@ public:
 
     static void updatePalette();
 
+    static QEvent::Type contextMenuEventType();
+
 protected:
     virtual void handleThemeChanged();
 
diff --git a/src/gui/kernel/qstylehints.cpp b/src/gui/kernel/qstylehints.cpp
index 0d15d114ec..73c6199733 100644
--- a/src/gui/kernel/qstylehints.cpp
+++ b/src/gui/kernel/qstylehints.cpp
@@ -443,6 +443,40 @@ void QStyleHints::setShowShortcutsInContextMenus(bool s)
 }
 
 /*!
+    \property QStyleHints::contextMenuTrigger
+    \since 6.8
+    \brief mouse event used to trigger a context menu event.
+
+    The default on UNIX systems is to show context menu on mouse button press event, while on
+    Windows it is the mouse button release event. This property can be used to override the default
+    platform behavior.
+
+    \note Developers must use this property with great care, as it changes the default interaction
+    mode that their users will expect on the platform that they are running on.
+
+    \sa Qt::ContextMenuTrigger
+*/
+Qt::ContextMenuTrigger QStyleHints::contextMenuTrigger() const
+{
+    Q_D(const QStyleHints);
+    if (d->m_contextMenuTrigger == -1) {
+        return themeableHint(QPlatformTheme::ContextMenuOnMouseRelease).toBool()
+                   ? Qt::ContextMenuTrigger::Release
+                   : Qt::ContextMenuTrigger::Press;
+    }
+    return Qt::ContextMenuTrigger(d->m_contextMenuTrigger);
+}
+
+void QStyleHints::setContextMenuTrigger(Qt::ContextMenuTrigger contextMenuTrigger)
+{
+    Q_D(QStyleHints);
+    const Qt::ContextMenuTrigger currentTrigger = this->contextMenuTrigger();
+    d->m_contextMenuTrigger = int(contextMenuTrigger);
+    if (currentTrigger != contextMenuTrigger)
+        emit contextMenuTriggerChanged(contextMenuTrigger);
+}
+
+/*!
     \property QStyleHints::passwordMaskDelay
     \brief the time, in milliseconds, a typed letter is displayed unshrouded
     in a text input field in password mode.
diff --git a/src/gui/kernel/qstylehints.h b/src/gui/kernel/qstylehints.h
index 8981383060..97ef59f3cf 100644
--- a/src/gui/kernel/qstylehints.h
+++ b/src/gui/kernel/qstylehints.h
@@ -36,6 +36,8 @@ class Q_GUI_EXPORT QStyleHints : public QObject
     Q_PROPERTY(bool showIsMaximized READ showIsMaximized STORED false CONSTANT FINAL)
     Q_PROPERTY(bool showShortcutsInContextMenus READ showShortcutsInContextMenus
                WRITE setShowShortcutsInContextMenus NOTIFY showShortcutsInContextMenusChanged FINAL)
+    Q_PROPERTY(Qt::ContextMenuTrigger contextMenuTrigger READ contextMenuTrigger WRITE
+                   setContextMenuTrigger NOTIFY contextMenuTriggerChanged FINAL)
     Q_PROPERTY(int startDragDistance READ startDragDistance NOTIFY startDragDistanceChanged FINAL)
     Q_PROPERTY(int startDragTime READ startDragTime NOTIFY startDragTimeChanged FINAL)
     Q_PROPERTY(int startDragVelocity READ startDragVelocity STORED false CONSTANT FINAL)
@@ -80,6 +82,8 @@ public:
     bool showIsMaximized() const;
     bool showShortcutsInContextMenus() const;
     void setShowShortcutsInContextMenus(bool showShortcutsInContextMenus);
+    Qt::ContextMenuTrigger contextMenuTrigger() const;
+    void setContextMenuTrigger(Qt::ContextMenuTrigger contextMenuTrigger);
     int passwordMaskDelay() const;
     QChar passwordMaskCharacter() const;
     qreal fontSmoothingGamma() const;
@@ -108,6 +112,7 @@ Q_SIGNALS:
     void tabFocusBehaviorChanged(Qt::TabFocusBehavior tabFocusBehavior);
     void useHoverEffectsChanged(bool useHoverEffects);
     void showShortcutsInContextMenusChanged(bool);
+    void contextMenuTriggerChanged(Qt::ContextMenuTrigger contextMenuTrigger);
     void wheelScrollLinesChanged(int scrollLines);
     void mouseQuickSelectionThresholdChanged(int threshold);
     void colorSchemeChanged(Qt::ColorScheme colorScheme);
diff --git a/src/gui/kernel/qstylehints_p.h b/src/gui/kernel/qstylehints_p.h
index 2b3979512a..497bf95cbf 100644
--- a/src/gui/kernel/qstylehints_p.h
+++ b/src/gui/kernel/qstylehints_p.h
@@ -35,6 +35,7 @@ public:
     int m_tabFocusBehavior = -1;
     int m_uiEffects = -1;
     int m_showShortcutsInContextMenus = -1;
+    int m_contextMenuTrigger = -1;
     int m_wheelScrollLines = -1;
     int m_mouseQuickSelectionThreshold = -1;
     int m_mouseDoubleClickDistance = -1;
diff --git a/src/gui/kernel/qwindow.cpp b/src/gui/kernel/qwindow.cpp
index b40fd7e8e8..7c885032c7 100644
--- a/src/gui/kernel/qwindow.cpp
+++ b/src/gui/kernel/qwindow.cpp
@@ -2654,16 +2654,14 @@ bool QWindow::event(QEvent *ev)
         This logic could be simplified by always synthesizing events in
         QGuiApplicationPrivate, or perhaps even in each QPA plugin. See QTBUG-93486.
     */
-    static const QEvent::Type contextMenuTrigger =
-        QGuiApplicationPrivate::platformTheme()->themeHint(QPlatformTheme::ContextMenuOnMouseRelease).toBool() ?
-        QEvent::MouseButtonRelease : QEvent::MouseButtonPress;
     auto asMouseEvent = [](QEvent *ev) {
         const auto t = ev->type();
         return t == QEvent::MouseButtonPress || t == QEvent::MouseButtonRelease
                 ? static_cast<QMouseEvent *>(ev) : nullptr ;
     };
-    if (QMouseEvent *me = asMouseEvent(ev); me &&
-        ev->type() == contextMenuTrigger && me->button() == Qt::RightButton) {
+    if (QMouseEvent *me = asMouseEvent(ev);
+        me && ev->type() == QGuiApplicationPrivate::contextMenuEventType()
+        && me->button() == Qt::RightButton) {
         QContextMenuEvent e(QContextMenuEvent::Mouse, me->position().toPoint(),
                             me->globalPosition().toPoint(), me->modifiers());
         QGuiApplication::sendEvent(this, &e);