File indexing completed on 2024-04-21 08:30:55

 /***************************************************************************
  *   Copyright (C) 2017-2018 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/>. *
  **************************************************************************/
 #include "flickablescrollbar.h"
 
 // KQuickItemViews
 #include "views/flickable.h"
 
 class FlickableScrollBarPrivate : public QObject
 {
     Q_OBJECT
 public:
     Flickable *m_pView        {nullptr};
     qreal      m_HandleHeight {   0   };
     qreal      m_Position     {   0   };
     bool       m_Visible      { false };
 
     FlickableScrollBar* q_ptr;
 
 public Q_SLOTS:
     void recomputeGeometry();
 };
 
 FlickableScrollBar::FlickableScrollBar(QQuickItem* parent) : QQuickItem(parent),
     d_ptr(new FlickableScrollBarPrivate)
 {
     d_ptr->q_ptr = this;
 }
 
 FlickableScrollBar::~FlickableScrollBar()
 {
     delete d_ptr;
 }
 
 QObject* FlickableScrollBar::view() const
 {
     return d_ptr->m_pView;
 }
 
 void FlickableScrollBar::setView(QObject* v)
 {
     if (d_ptr->m_pView) {
         disconnect(d_ptr->m_pView, &Flickable::contentHeightChanged,
             d_ptr, &FlickableScrollBarPrivate::recomputeGeometry);
         disconnect(d_ptr->m_pView, &Flickable::contentYChanged,
             d_ptr, &FlickableScrollBarPrivate::recomputeGeometry);
         disconnect(d_ptr->m_pView, &Flickable::heightChanged,
             d_ptr, &FlickableScrollBarPrivate::recomputeGeometry);
     }
 
     d_ptr->m_pView = qobject_cast<Flickable*>(v);
 
     Q_ASSERT((!v) || d_ptr->m_pView);
 
     connect(d_ptr->m_pView, &Flickable::contentHeightChanged,
         d_ptr, &FlickableScrollBarPrivate::recomputeGeometry);
     connect(d_ptr->m_pView, &Flickable::contentYChanged,
         d_ptr, &FlickableScrollBarPrivate::recomputeGeometry);
     connect(d_ptr->m_pView, &Flickable::heightChanged,
         d_ptr, &FlickableScrollBarPrivate::recomputeGeometry);
 
     d_ptr->recomputeGeometry();
 }
 
 qreal FlickableScrollBar::position() const
 {
     return d_ptr->m_Position;
 }
 
 void FlickableScrollBar::setPosition(qreal p)
 {
     if (!d_ptr->m_pView)
         return;
 
     // Simple rule of 3
     d_ptr->m_pView->setContentY(
         (p * d_ptr->m_pView->contentHeight()) / d_ptr->m_pView->height()
     );
 }
 
 qreal FlickableScrollBar::handleHeight() const
 {
     return d_ptr->m_HandleHeight;
 }
 
 bool FlickableScrollBar::isHandleVisible() const
 {
     return d_ptr->m_Visible;
 }
 
 /**
  * The idea behind the scrollhandle is that the height represent the height of a
  * page until it gets too small. In mobile mode, the height is always the same
  * regardless of the content height to hide less space on the smaller screen.
  */
 void FlickableScrollBarPrivate::recomputeGeometry()
 {
     if (!m_pView)
         return;
 
     const qreal oldP = m_Position;
     const qreal oldH = m_HandleHeight;
 
     const qreal totalHeight  = m_pView->contentHeight();
     const qreal pageHeight   = m_pView->height();
     const qreal pageCount    = totalHeight/pageHeight;
     const qreal handleHeight = std::max(pageHeight/pageCount, 50.0);
     const qreal handleBegin  = (m_pView->contentY()*pageHeight)/totalHeight;
 
     m_HandleHeight = handleHeight;
     m_Position     = handleBegin;
     m_Visible      = totalHeight > pageHeight;
 
     if (oldH != m_HandleHeight)
         emit q_ptr->handleHeightChanged();
 
     if (oldP != m_Position)
         emit q_ptr->positionChanged ();
 }
 
 #include <flickablescrollbar.moc>