File indexing completed on 2024-04-21 03:56:01

 /*
  *  SPDX-FileCopyrightText: 2023 ivan tkachenko <me@ratijas.tk>
  *
  *  SPDX-License-Identifier: LGPL-2.0-or-later
  */
 
 #ifndef OVERLAYZSTACKINGATTACHED_H
 #define OVERLAYZSTACKINGATTACHED_H
 
 #include <QObject>
 #include <QQmlEngine>
 
 #include <qqmlregistration.h>
 
 class QQuickItem;
 
 /**
  * This attached property manages z-index for stacking overlays relative to each other.
  *
  * When a popup is about to show, OverlayZStacking object kicks in, searches for the
  * next nearest popup in the QtQuick hierarchy of items, and sets its z value to the
  * biggest of two: current stacking value for its layer, or parent's z index + 1.
  * This way OverlayZStacking algorithm ensures that a popup is always stacked higher
  * than its logical parent popup, but also no lower than its siblings on the same
  * logical layer.
  *
  * @code
  * import QtQuick.Controls as QQC2
  * import org.kde.kirigami as Kirigami
  *
  * QQC2.Popup {
  *     Kirigami.OverlayZStacking.layer: Kirigami.OverlayZStacking.ToolTip
  *     z: Kirigami.OverlayZStacking.z
  * }
  * @endcode
  *
  * @since 6.0
  */
 class OverlayZStackingAttached : public QObject
 {
     Q_OBJECT
     QML_ELEMENT
     QML_NAMED_ELEMENT(OverlayZStacking)
     QML_UNCREATABLE("Cannot create objects of type OverlayZStacking, use it as an attached property")
     QML_ATTACHED(OverlayZStackingAttached)
     /**
      * An optimal z-index that attachee popup should bind to.
      */
     Q_PROPERTY(qreal z READ z NOTIFY zChanged FINAL)
 
     /**
      * The logical stacking layer of attachee popup, akin to window manager's layers.
      */
     Q_PROPERTY(Layer layer READ layer WRITE setLayer NOTIFY layerChanged FINAL)
 
 public:
     enum Layer {
         DefaultLowest = 0,
         Drawer,
         FullScreen,
         Dialog,
         Menu,
         Notification,
         ToolTip,
     };
     Q_ENUM(Layer)
 
     explicit OverlayZStackingAttached(QObject *parent = nullptr);
     ~OverlayZStackingAttached() override;
 
     qreal z() const;
 
     Layer layer() const;
     void setLayer(Layer layer);
 
     // QML attached property
     static OverlayZStackingAttached *qmlAttachedProperties(QObject *object);
 
 Q_SIGNALS:
     void zChanged();
     void layerChanged();
 
 private Q_SLOTS:
     // Popup shall not change z index while being open, so if changes arrive, we defer it until closed.
     void enqueueSignal();
     void dispatchPendingSignal();
 
     void updateParentPopup();
 
 private:
     void updateParentPopupSilent();
     void setParentPopup(QObject *popup);
     qreal parentPopupZ() const;
     static bool isVisible(const QObject *popup);
     static bool isPopup(const QObject *object);
     static QObject *findParentPopup(const QObject *popup);
     static QQuickItem *findParentPopupItem(const QObject *popup);
     static Layer defaultLayerForPopupType(const QObject *popup);
     static qreal defaultZForLayer(Layer layer);
 
     Layer m_layer = Layer::DefaultLowest;
     QPointer<QObject> m_parentPopup;
     bool m_pending;
 };
 
 QML_DECLARE_TYPEINFO(OverlayZStackingAttached, QML_HAS_ATTACHED_PROPERTIES)
 
 #endif // OVERLAYZSTACKINGATTACHED_H