File indexing completed on 2024-04-28 04:41:52

 /***************************************************************************
  *   Copyright (C) 2017 by Emmanuel Lepage Vallee                          *
  *   Author : Emmanuel Lepage Vallee <emmanuel.lepage@kde.org>             *
  *                                                                         *
  *   This program is free software; you can redistribute it and/or modify  *
  *   it under the terms of the GNU General Public License as published by  *
  *   the Free Software Foundation; either version 3 of the License, or     *
  *   (at your option) any later version.                                   *
  *                                                                         *
  *   This program is distributed in the hope that it will be useful,       *
  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  *   GNU General Public License for more details.                          *
  *                                                                         *
  *   You should have received a copy of the GNU General Public License     *
  *   along with this program.  If not, see <http://www.gnu.org/licenses/>. *
  **************************************************************************/
 #ifndef FLICKABLE_H
 #define FLICKABLE_H
 
 #include <QQuickItem>
 
 class FlickablePrivate;
 
 /**
  * This file re-implements the flickable view.
  *
  * It is necessary to avoid a dependency on Qt private APIs in order to
  * re-implement higher level views such as the tree view. The upstream code
  * could also hardly have been copy/pasted in this project as it depends on
  * yet more hidden APIs and the code (along with dependencies) is over an order
  * or magnitude larger than this implementation. It would have been a
  * maintainability nightmare.
  *
  * This implementation is API compatible with a small subset of the Flickable
  * properties and uses a 200 lines of code inertial state machine instead of
  * 1.5k line of vomit code to do the exact same job.
  */
 class Q_DECL_EXPORT Flickable : public QQuickItem
 {
     Q_OBJECT
 public:
     // Implement some of the QtQuick2.Flickable API
     Q_PROPERTY(qreal contentY READ contentY WRITE setContentY NOTIFY contentYChanged)
     Q_PROPERTY(qreal contentHeight READ contentHeight NOTIFY contentHeightChanged )
     Q_PROPERTY(bool dragging READ isDragging NOTIFY draggingChanged)
     Q_PROPERTY(bool flicking READ isDragging NOTIFY movingChanged)
     Q_PROPERTY(bool moving READ isDragging NOTIFY movingChanged)
     Q_PROPERTY(bool movingHorizontally READ isDragging NOTIFY movingChanged)
     Q_PROPERTY(bool draggingHorizontally READ isDragging NOTIFY draggingChanged)
     Q_PROPERTY(bool flickingHorizontally READ isDragging NOTIFY movingChanged)
     Q_PROPERTY(qreal flickDeceleration READ flickDeceleration WRITE setFlickDeceleration)
     Q_PROPERTY(bool interactive READ isInteractive WRITE setInteractive)
     Q_PROPERTY(qreal maximumFlickVelocity READ maximumFlickVelocity  WRITE setMaximumFlickVelocity)
 
     /**
      * The geometry of the content subset currently displayed be the Flickable.
      *
      * It is usually {0, contentY, height, width}.
      */
     Q_PROPERTY(QRectF viewport READ viewport NOTIFY viewportChanged)
 
     explicit Flickable(QQuickItem* parent = nullptr);
     virtual ~Flickable();
 
     qreal contentY() const;
     virtual void setContentY(qreal y);
 
     QRectF viewport() const;
 
     qreal contentHeight() const;
 
     QQuickItem* contentItem();
 
     bool isDragging() const;
     bool isMoving() const;
 
     qreal flickDeceleration() const;
     void setFlickDeceleration(qreal v);
 
     bool isInteractive() const;
     void setInteractive(bool v);
 
     qreal maximumFlickVelocity() const;
     void setMaximumFlickVelocity(qreal v);
 
     QQmlContext* rootContext() const;
 
 Q_SIGNALS:
     void contentHeightChanged(qreal height);
     void contentYChanged(qreal y);
     void percentageChanged(qreal percent);
     void draggingChanged(bool dragging);
     void movingChanged(bool dragging);
     void viewportChanged(const QRectF &view);
 
 protected:
     bool event(QEvent *ev) override;
     bool childMouseEventFilter(QQuickItem *, QEvent *) override;
     void geometryChanged(const QRectF& newGeometry, const QRectF& oldGeometry) override;
 
 private:
     FlickablePrivate* d_ptr;
     Q_DECLARE_PRIVATE(Flickable)
 };
 
 #endif