Support masking of QQuickItems

Adding a new property, containsMask, to QQuickItem, that can be set
to any QObject defining a
Q_INVOKABLE bool contains(const QPointF &point).
When this property is set, the mask object contains method is used in
place of the item own contains method.

[ChangeLog][QtQuick][QQuickItem] Added containsMask property.

Task-number: QTBUG-20524
Change-Id: I5b0696e2cddc6ae3e217ce149c5f44980fdb69aa
Reviewed-by: Jan Arve Sæther <jan-arve.saether@qt.io>
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

1 files changed, 7 insertions, 0 deletions

diff --git a/src/quick/items/qquickitem_p.h b/src/quick/items/qquickitem_p.h
index 9ed5286f22..0c02c66ef2 100644
--- a/src/quick/items/qquickitem_p.h
+++ b/src/quick/items/qquickitem_p.h
@@ -368,6 +368,9 @@ public:
         QQuickDefaultClipNode *clipNode;
         QSGRootNode *rootNode;
 
+        // Mask contains() method
+        QMetaMethod maskContains;
+
         QObjectList resourcesList;
 
         // Although acceptedMouseButtons is inside ExtraData, we actually store
@@ -382,6 +385,10 @@ public:
         // 26 bits padding
     };
     QLazilyAllocated<ExtraData> extra;
+    // Contains mask
+    QPointer<QObject> mask;
+    // If the mask is an Item, inform it that it's being used as a mask (true) or is no longer being used (false)
+    virtual void registerAsContainsMask(QQuickItem * /* maskedItem */, bool /* set */) { }
 
     QQuickAnchors *anchors() const;
     mutable QQuickAnchors *_anchors;