QML API for subsurfaces

Task-number: QTBUG-49809
Change-Id: I433fd5ee4d920e6fc6696627b45738631ab329c4
Reviewed-by: Pier Luigi Fiorini <pierluigi.fiorini@gmail.com>

3 files changed, 76 insertions, 2 deletions

diff --git a/src/compositor/compositor_api/qwaylandquickitem.cpp b/src/compositor/compositor_api/qwaylandquickitem.cpp
index bee12b4a5..ded65e87f 100644
--- a/src/compositor/compositor_api/qwaylandquickitem.cpp
+++ b/src/compositor/compositor_api/qwaylandquickitem.cpp
@@ -486,6 +486,62 @@ void QWaylandQuickItem::surfaceChangedEvent(QWaylandSurface *newSurface, QWaylan
     Q_UNUSED(oldSurface);
 }
 
+void QWaylandQuickItem::handleSubsurfaceAdded(QWaylandSurface *childSurface)
+{
+    Q_D(QWaylandQuickItem);
+    if (d->subsurfaceHandler.isNull()) {
+        QWaylandQuickItem *childItem = new QWaylandQuickItem;
+        childItem->setSurface(childSurface);
+        childItem->setVisible(true);
+        childItem->setParentItem(this);
+        connect(childSurface, &QWaylandSurface::subsurfacePositionChanged, childItem, &QWaylandQuickItem::handleSubsurfacePosition);
+    } else {
+        bool success = QMetaObject::invokeMethod(d->subsurfaceHandler, "handleSubsurfaceAdded", Q_ARG(QWaylandSurface *, childSurface));
+        if (!success)
+            qWarning("QWaylandQuickItem: subsurfaceHandler does not implement handleSubsurfaceAdded()");
+    }
+}
+
+
+
+/*!
+  \qmlproperty bool QtWaylandCompositor::WaylandQuickItem::subsurfaceHandler
+
+  This property provides a way to override the default subsurface behavior.
+
+  By default, Qt will create a new SurfaceItem as a child of this item, and maintain the correct position.
+
+  To override the default, assign a handler object to this property. The handler should implement
+  a handleSubsurfaceAdded(WaylandSurface) function.
+
+  \code
+  ShellSurfaceItem {
+      subsurfaceHandler: QtObject {
+      function handleSubsurfaceAdded(child) {
+        //create custom surface item, and connect the subsurfacePositionChanged signal
+      }
+  }
+  \endcode
+
+  The default value of this property is \c null.
+ */
+
+
+QObject *QWaylandQuickItem::subsurfaceHandler() const
+{
+    Q_D(const QWaylandQuickItem);
+    return d->subsurfaceHandler.data();
+}
+
+void QWaylandQuickItem::setSubsurfaceHandler(QObject *handler)
+{
+    Q_D(QWaylandQuickItem);
+    if (d->subsurfaceHandler.data() != handler) {
+        d->subsurfaceHandler = handler;
+        emit subsurfaceHandlerChanged();
+    }
+}
+
 /*!
  * \internal
  */
@@ -498,6 +554,7 @@ void QWaylandQuickItem::handleSurfaceChanged()
         disconnect(d->oldSurface, &QWaylandSurface::sizeChanged, this, &QWaylandQuickItem::updateSize);
         disconnect(d->oldSurface, &QWaylandSurface::configure, this, &QWaylandQuickItem::updateBuffer);
         disconnect(d->oldSurface, &QWaylandSurface::redraw, this, &QQuickItem::update);
+        disconnect(d->oldSurface, &QWaylandSurface::childAdded, this, &QWaylandQuickItem::handleSubsurfaceAdded);
 #ifndef QT_NO_IM
         disconnect(d->oldSurface->inputMethodControl(), &QWaylandInputMethodControl::updateInputMethod, this, &QWaylandQuickItem::updateInputMethod);
 #endif
@@ -508,6 +565,7 @@ void QWaylandQuickItem::handleSurfaceChanged()
         connect(newSurface, &QWaylandSurface::sizeChanged, this, &QWaylandQuickItem::updateSize);
         connect(newSurface, &QWaylandSurface::configure, this, &QWaylandQuickItem::updateBuffer);
         connect(newSurface, &QWaylandSurface::redraw, this, &QQuickItem::update);
+        connect(newSurface, &QWaylandSurface::childAdded, this, &QWaylandQuickItem::handleSubsurfaceAdded);
 #ifndef QT_NO_IM
         connect(newSurface->inputMethodControl(), &QWaylandInputMethodControl::updateInputMethod, this, &QWaylandQuickItem::updateInputMethod);
 #endif
@@ -835,4 +893,14 @@ void QWaylandQuickItem::raise()
         stackAfter(top);
 }
 
+/*!
+ * \internal
+ *
+ * Sets the position of this item relative to the parent item.
+ */
+void QWaylandQuickItem::handleSubsurfacePosition(const QPoint &pos)
+{
+    QQuickItem::setPosition(pos);
+}
+
 QT_END_NAMESPACE
diff --git a/src/compositor/compositor_api/qwaylandquickitem.h b/src/compositor/compositor_api/qwaylandquickitem.h
index 9dab65acf..20b28b5f0 100644
--- a/src/compositor/compositor_api/qwaylandquickitem.h
+++ b/src/compositor/compositor_api/qwaylandquickitem.h
@@ -67,7 +67,7 @@ class Q_WAYLAND_COMPOSITOR_EXPORT QWaylandQuickItem : public QQuickItem
     Q_PROPERTY(bool inputEventsEnabled READ inputEventsEnabled WRITE setInputEventsEnabled NOTIFY inputEventsEnabledChanged)
     Q_PROPERTY(bool focusOnClick READ focusOnClick WRITE setFocusOnClick NOTIFY focusOnClickChanged)
     Q_PROPERTY(bool sizeFollowsSurface READ sizeFollowsSurface WRITE setSizeFollowsSurface NOTIFY sizeFollowsSurfaceChanged)
-
+    Q_PROPERTY(QObject *subsurfaceHandler READ subsurfaceHandler WRITE setSubsurfaceHandler NOTIFY subsurfaceHandlerChanged)
 public:
     QWaylandQuickItem(QQuickItem *parent = 0);
     ~QWaylandQuickItem();
@@ -104,6 +104,9 @@ public:
     Q_INVOKABLE QVariant inputMethodQuery(Qt::InputMethodQuery query, QVariant argument) const;
 #endif
 
+    QObject *subsurfaceHandler() const;
+    void setSubsurfaceHandler(QObject*);
+
 protected:
     void mousePressEvent(QMouseEvent *event) Q_DECL_OVERRIDE;
     void mouseMoveEvent(QMouseEvent *event) Q_DECL_OVERRIDE;
@@ -138,6 +141,8 @@ private Q_SLOTS:
     void updateBuffer(bool hasBuffer);
     void updateWindow();
     void beforeSync();
+    void handleSubsurfaceAdded(QWaylandSurface *childSurface);
+    void handleSubsurfacePosition(const QPoint &pos);
 #ifndef QT_NO_IM
     void updateInputMethod(Qt::InputMethodQueries queries);
 #endif
@@ -152,7 +157,7 @@ Q_SIGNALS:
     void mouseMove(const QPointF &windowPosition);
     void mouseRelease();
     void sizeFollowsSurfaceChanged();
-
+    void subsurfaceHandlerChanged();
 protected:
     QSGNode *updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData *) Q_DECL_OVERRIDE;
 
diff --git a/src/compositor/compositor_api/qwaylandquickitem_p.h b/src/compositor/compositor_api/qwaylandquickitem_p.h
index 2a5686f33..62c01aceb 100644
--- a/src/compositor/compositor_api/qwaylandquickitem_p.h
+++ b/src/compositor/compositor_api/qwaylandquickitem_p.h
@@ -119,6 +119,7 @@ public:
 
     QQuickWindow *connectedWindow;
     QWaylandSurface::Origin origin;
+    QPointer<QObject> subsurfaceHandler;
 };
 
 QT_END_NAMESPACE