src/panels/folders/ktreeview.cpp

   1 /***************************************************************************
   2  *   Copyright (C) 2008 by <haraldhv (at) stud.ntnu.no>                    *
   3  *   Copyright (C) 2008 by <peter.penz@gmx.at>                             *
   4  *                                                                         *
   5  *   This program is free software; you can redistribute it and/or modify  *
   6  *   it under the terms of the GNU General Public License as published by  *
   7  *   the Free Software Foundation; either version 2 of the License, or     *
   8  *   (at your option) any later version.                                   *
   9  *                                                                         *
  10  *   This program is distributed in the hope that it will be useful,       *
  11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  13  *   GNU General Public License for more details.                          *
  14  *                                                                         *
  15  *   You should have received a copy of the GNU General Public License     *
  16  *   along with this program; if not, write to the                         *
  17  *   Free Software Foundation, Inc.,                                       *
  18  *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA            *
  19  ***************************************************************************/
  20
  21 #include "ktreeview.h"
  22 #include "ktreeview_p.h"
  23
  24 #include <KGlobalSettings>
  25
  26 #include <QItemSelectionModel>
  27 #include <QScrollBar>
  28 #include <QTimer>
  29 #include <QTimeLine>
  30
  31 KTreeView::KTreeViewPrivate::KTreeViewPrivate(KTreeView *parent) :
  32     parent(parent),
  33     autoHorizontalScroll(false),
  34     timeLine(0)
  35 {
  36     timeLine = new QTimeLine(500, this);
  37     connect(timeLine, SIGNAL(frameChanged(int)),
  38             this, SLOT(updateVerticalScrollBar(int)));
  39
  40     connect(parent->verticalScrollBar(), SIGNAL(rangeChanged(int, int)),
  41             this, SLOT(startScrolling()));
  42     connect(parent->verticalScrollBar(), SIGNAL(valueChanged(int)),
  43             this, SLOT(startScrolling()));
  44     connect(parent, SIGNAL(collapsed(const QModelIndex&)),
  45             this, SLOT(startScrolling()));
  46     connect(parent, SIGNAL(expanded(const QModelIndex&)),
  47             this, SLOT(startScrolling()));
  48 }
  49
  50 void KTreeView::KTreeViewPrivate::startScrolling()
  51 {
  52     if (!autoHorizontalScroll) {
  53         return;
  54     }
  55
  56     // Determine the most left visual index
  57     QModelIndex visibleIndex = parent->indexAt(QPoint(0, 0));
  58     if (!visibleIndex.isValid()) {
  59         return;
  60     }
  61
  62     QModelIndex index = visibleIndex;
  63     int minimum = parent->width();
  64     do {
  65         const QRect rect = parent->visualRect(visibleIndex);
  66         if (rect.top() > parent->viewport()->height()) {
  67             // the current index and all successors are not visible anymore
  68             break;
  69         }
  70         if (rect.left() < minimum) {
  71             minimum = rect.left();
  72             index = visibleIndex;
  73         }
  74         visibleIndex = parent->indexBelow(visibleIndex);
  75     } while (visibleIndex.isValid());
  76
  77     // Start the horizontal scrolling to assure that the item indicated by 'index' gets fully visible
  78     Q_ASSERT(index.isValid());
  79     const QRect rect = parent->visualRect(index);
  80
  81     QScrollBar* scrollBar = parent->horizontalScrollBar();
  82     const int oldScrollBarPos = scrollBar->value();
  83
  84     const int itemRight = oldScrollBarPos + rect.left() + rect.width() - 1;
  85     const int availableWidth = parent->viewport()->width();
  86     int scrollBarPos = itemRight - availableWidth;
  87     const int scrollBarPosMax = oldScrollBarPos + rect.left() - parent->indentation();
  88     if (scrollBarPos > scrollBarPosMax) {
  89         scrollBarPos = scrollBarPosMax;
  90     }
  91
  92     if (scrollBarPos != oldScrollBarPos) {
  93         timeLine->setFrameRange(oldScrollBarPos, scrollBarPos);
  94         timeLine->start();
  95     }
  96 }
  97
  98 void KTreeView::KTreeViewPrivate::updateVerticalScrollBar(int value)
  99 {
 100     QScrollBar *scrollBar = parent->horizontalScrollBar();
 101     scrollBar->setValue(value);
 102 }
 103
 104 // ************************************************
 105
 106 KTreeView::KTreeView(QWidget *parent) :
 107     QTreeView(parent),
 108     d(new KTreeViewPrivate(this))
 109 {
 110     if (KGlobalSettings::graphicEffectsLevel() >= KGlobalSettings::SimpleAnimationEffects) {
 111         setAutoHorizontalScroll(true);
 112     }
 113 }
 114
 115 KTreeView::~KTreeView()
 116 {
 117 }
 118
 119 void KTreeView::setAutoHorizontalScroll(bool enable)
 120 {
 121     d->autoHorizontalScroll = enable;
 122     if (!enable) {
 123         d->timeLine->stop();
 124     }
 125 }
 126
 127 bool KTreeView::autoHorizontalScroll() const
 128 {
 129     return d->autoHorizontalScroll;
 130 }
 131
 132 void KTreeView::scrollTo(const QModelIndex& index, ScrollHint hint)
 133 {
 134     const int value = horizontalScrollBar()->value();
 135     QTreeView::scrollTo(index, hint);
 136     horizontalScrollBar()->setValue(value);
 137 }
 138
 139 void KTreeView::hideEvent(QHideEvent *event)
 140 {
 141     d->timeLine->stop();
 142     QTreeView::hideEvent(event);
 143 }
 144
 145 #include "ktreeview.moc"
 146 #include "ktreeview_p.moc"