workarounds for mouse grabbing

src/controls/QskGestureRecognizer.cpp

@@ -1,5 +1,6 @@
 #include "QskGestureRecognizer.h"
 #include "QskEvent.h"
+#include "QskQuick.h"
 
 #include <qbasictimer.h>
 #include <qcoreapplication.h>
@@ -55,44 +56,6 @@ static inline QMouseEvent* qskClonedMouseEvent(
     return clonedEvent;
 }
 
-static void qskGrabTouchMouse( QQuickItem* item )
-{
-#if QT_VERSION >= QT_VERSION_CHECK( 5, 8, 0 ) && QT_VERSION < QT_VERSION_CHECK( 6, 0, 0 )
-    auto wd = QQuickWindowPrivate::get( item->window() );
-
-    if ( wd->touchMouseDevice == nullptr )
-    {
-        /*
-            For synthesized mouse events QQuickWindow sends
-            an initial QEvent::MouseButtonPress before setting
-            touchMouseDevice/touchMouseId and a call of grabMouse
-            is stored in a pointerEvent for the generic mouse device.
-            Then all following synthesized mouse events are not grabbed
-            properly.
-        */
-
-        for ( const auto event : wd->pointerEventInstances )
-        {
-            if ( auto touchEvent = event->asPointerTouchEvent() )
-            {
-                if ( touchEvent->isPressEvent() )
-                {
-                    if ( const auto p = touchEvent->point( 0 ) )
-                    {
-                        wd->touchMouseDevice = touchEvent->device();
-                        wd->touchMouseId = p->pointId();
-                    }
-
-                    break;
-                }
-            }
-        }
-    }
-#endif
-
-    item->grabMouse();
-}
-
 namespace
 {
     /*
@@ -348,20 +311,6 @@ bool QskGestureRecognizer::processEvent(
             return false;
         }
 
-        auto mouseGrabber = watchedItem->window()->mouseGrabberItem();
-        if ( mouseGrabber && ( mouseGrabber != watchedItem ) )
-        {
-            if ( mouseGrabber->keepMouseGrab() || mouseGrabber->keepTouchGrab() )
-            {
-                /*
-                    Another child has grabbed mouse/touch and is not willing to
-                    be intercepted: we respect this.
-                 */
-
-                return false;
-            }
-        }
-
         Qt::MouseButtons buttons = m_data->buttons;
         if ( buttons == Qt::NoButton )
             buttons = watchedItem->acceptedMouseButtons();
@@ -371,11 +320,11 @@ bool QskGestureRecognizer::processEvent(
             return false;
 
         /*
-            We grab the mouse for watchedItem and indicate, that we want
-            to keep it. From now on all mouse events should end up at watchedItem.
+            We try to grab the mouse for watchedItem and indicate, that we want
+            to keep it. Then all mouse events should end up at watchedItem.
          */
-        qskGrabTouchMouse( watchedItem );
-        watchedItem->setKeepMouseGrab( true );
+        if ( !qskGrabMouse( watchedItem ) )
+            return false;
 
         m_data->timestamp = mouseEvent->timestamp();
 
@@ -509,11 +458,7 @@ void QskGestureRecognizer::reject()
 
     m_data->isReplayingEvents = true;
 
-    if ( window->mouseGrabberItem() == watchedItem )
-    {
-        watchedItem->setKeepMouseGrab( false );
-        watchedItem->ungrabMouse();
-    }
+    qskUngrabMouse( watchedItem );
 
     if ( !events.isEmpty() &&
         ( events[ 0 ]->type() == QEvent::MouseButtonPress ) )
@@ -544,11 +489,7 @@ void QskGestureRecognizer::reset()
 {
     qskTimerTable->stopTimer( this );
 
-    if ( auto item = m_data->watchedItem )
-    {
-        item->setKeepMouseGrab( false );
-        item->ungrabMouse();
-    }
+    qskUngrabMouse( m_data->watchedItem );
 
     m_data->pendingEvents.reset();
     m_data->timestamp = 0;

src/controls/QskQuick.cpp

@@ -640,3 +640,99 @@ void qskItemUpdateRecursive( QQuickItem* item )
     for ( auto child : children )
         qskItemUpdateRecursive( child );
 }
+
+#if QT_VERSION >= QT_VERSION_CHECK( 5, 8, 0 ) && QT_VERSION < QT_VERSION_CHECK( 6, 0, 0 )
+
+static const QQuickPointerTouchEvent* qskPointerPressEvent( const QQuickWindowPrivate* wd )
+{
+    for ( const auto event : wd->pointerEventInstances )
+    {
+        if ( auto touchEvent = event->asPointerTouchEvent() )
+        {
+            if ( touchEvent->isPressEvent() )
+                return touchEvent;
+        }
+    }
+
+    return nullptr;
+}
+
+#endif
+
+bool qskGrabMouse( QQuickItem* item )
+{
+    if ( item == nullptr || item->window() == nullptr )
+        return false;
+
+    if ( const auto mouseGrabber = item->window()->mouseGrabberItem() )
+    {
+        if ( mouseGrabber == item )
+            return true;
+
+        if ( mouseGrabber->keepMouseGrab() )
+        {
+            // we respect this
+            return false;
+        }
+    }
+
+    item->setKeepMouseGrab( true );
+
+#if QT_VERSION >= QT_VERSION_CHECK( 5, 8, 0 ) && QT_VERSION < QT_VERSION_CHECK( 6, 0, 0 )
+
+    auto wd = QQuickWindowPrivate::get( item->window() );
+    if ( wd->touchMouseDevice == nullptr )
+    {
+        /*
+            For synthesized mouse events QQuickWindow sends
+            an initial QEvent::MouseButtonPress before setting
+            touchMouseDevice/touchMouseId. As the mouse grabber is
+            stored depending on these attributes the following
+            mouse event callbacks will look for the grabber at a
+            a different place as it was stored.
+        */
+
+        if ( const auto event = qskPointerPressEvent( wd ) )
+        {
+            if ( const auto p = event->point( 0 ) )
+            {
+                wd->touchMouseDevice = event->device();
+                wd->touchMouseId = p->pointId();
+
+                item->grabMouse();
+
+                wd->touchMouseDevice = nullptr;
+                wd->touchMouseId = -1;
+
+                return true;
+            }
+        }
+    }
+#endif
+
+    item->grabMouse();
+    return true;
+}
+
+void qskUngrabMouse( QQuickItem* item )
+{
+    if ( item )
+    {
+        item->setKeepMouseGrab( false );
+
+        if ( qskIsMouseGrabber( item ) )
+            item->ungrabMouse();
+
+    }
+}
+
+bool qskIsMouseGrabber( const QQuickItem* item )
+{
+    if ( item )
+    {
+        if ( const auto window = item->window() )
+            return window->mouseGrabberItem() == item;
+    }
+
+    return false;
+}

src/controls/QskQuick.h

@@ -67,6 +67,10 @@ QSK_EXPORT const QSGNode* qskPaintNode( const QQuickItem* );
 
 QSK_EXPORT void qskItemUpdateRecursive( QQuickItem* );
 
+QSK_EXPORT bool qskGrabMouse( QQuickItem* );
+QSK_EXPORT void qskUngrabMouse( QQuickItem* );
+QSK_EXPORT bool qskIsMouseGrabber( const QQuickItem* );
+
 inline void qskSetItemGeometry(
     QQuickItem* item, qreal x, qreal y, qreal width, qreal height )
 {

src/dialogs/QskDialogSubWindow.cpp

@@ -258,7 +258,7 @@ QskDialog::DialogCode QskDialogSubWindow::exec()
         // the mouse grabber has not yet been released.
 
         if( !qskIsAncestorOf( this, mouseGrabber ) )
-            mouseGrabber->ungrabMouse();
+            qskUngrabMouse( mouseGrabber );
     }
 
     QEventLoop eventLoop;