src/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 <QEvent>
  27 #include <QItemSelectionModel>
  28 #include <QScrollBar>
  29 #include <QTimer>
  30 #include <QTimeLine>
  31
  32 KTreeView::KTreeViewPrivate::KTreeViewPrivate(KTreeView *parent) :
  33     parent(parent),
  34     autoHorizontalScroll(false),
  35     timeLine(0),
  36     startScrollTimer(0)
  37 {
  38     startScrollTimer = new QTimer(this);
  39     startScrollTimer->setSingleShot(true);
  40     startScrollTimer->setInterval(300);
  41
  42     timeLine = new QTimeLine(300, this);
  43 }
  44
  45 void KTreeView::KTreeViewPrivate::connectScrollTimers()
  46 {
  47     connect(startScrollTimer, SIGNAL(timeout()),
  48             this, SLOT(startScrolling()));
  49
  50     connect(timeLine, SIGNAL(frameChanged(int)),
  51             this, SLOT(updateVerticalScrollBar(int)));
  52
  53     connect(parent->verticalScrollBar(), SIGNAL(rangeChanged(int, int)),
  54             startScrollTimer, SLOT(start()));
  55     connect(parent->verticalScrollBar(), SIGNAL(valueChanged(int)),
  56             startScrollTimer, SLOT(start()));
  57     connect(parent, SIGNAL(collapsed(const QModelIndex&)),
  58             startScrollTimer, SLOT(start()));
  59     connect(parent, SIGNAL(expanded(const QModelIndex&)),
  60             startScrollTimer, SLOT(start()));
  61 }
  62
  63 void KTreeView::KTreeViewPrivate::startScrolling()
  64 {
  65     QModelIndex index;
  66
  67     const int viewportHeight = parent->viewport()->height();
  68
  69     // check whether there is a selected index which is partly visible
  70     const QModelIndexList selectedIndexes = parent->selectionModel()->selectedIndexes();
  71     if (selectedIndexes.count() == 1) {
  72         QModelIndex selectedIndex = selectedIndexes.first();
  73         const QRect rect = parent->visualRect(selectedIndex);
  74         if ((rect.bottom() >= 0) && (rect.top() <= viewportHeight)) {
  75             // the selected index is (at least partly) visible, use it as
  76             // scroll target
  77             index = selectedIndex;
  78         }
  79     }
  80
  81     if (!index.isValid()) {
  82         // no partly selected index is visible, determine the most left visual index
  83         QModelIndex visibleIndex = parent->indexAt(QPoint(0, 0));
  84         if (!visibleIndex.isValid()) {
  85             return;
  86         }
  87
  88         index = visibleIndex;
  89         int minimum = parent->width();
  90         do {
  91             const QRect rect = parent->visualRect(visibleIndex);
  92             if (rect.top() > viewportHeight) {
  93                 // the current index and all successors are not visible anymore
  94                 break;
  95             }
  96             if (rect.left() < minimum) {
  97                 minimum = rect.left();
  98                 index = visibleIndex;
  99             }
 100             visibleIndex = parent->indexBelow(visibleIndex);
 101         } while (visibleIndex.isValid());
 102     }
 103
 104     // start the horizontal scrolling to assure that the item indicated by 'index' gets fully visible
 105     Q_ASSERT(index.isValid());
 106     const QRect rect = parent->visualRect(index);
 107
 108     QScrollBar *scrollBar = parent->horizontalScrollBar();
 109     const int oldScrollBarPos = scrollBar->value();
 110
 111     const int itemRight = oldScrollBarPos + rect.left() + rect.width() - 1;
 112     const int availableWidth = parent->viewport()->width();
 113     int scrollBarPos = itemRight - availableWidth;
 114     const int scrollBarPosMax = oldScrollBarPos + rect.left() - parent->indentation();
 115     if (scrollBarPos > scrollBarPosMax) {
 116         scrollBarPos = scrollBarPosMax;
 117     }
 118
 119     if (scrollBarPos != oldScrollBarPos) {
 120         timeLine->setFrameRange(oldScrollBarPos, scrollBarPos);
 121         timeLine->start();
 122     }
 123 }
 124
 125 void KTreeView::KTreeViewPrivate::updateVerticalScrollBar(int value)
 126 {
 127     QScrollBar *scrollBar = parent->horizontalScrollBar();
 128     scrollBar->setValue(value);
 129     startScrollTimer->stop();
 130 }
 131
 132 // ************************************************
 133
 134 KTreeView::KTreeView(QWidget *parent) :
 135     QTreeView(parent),
 136     d(new KTreeViewPrivate(this))
 137 {
 138     if (KGlobalSettings::graphicEffectsLevel() >= KGlobalSettings::SimpleAnimationEffects) {
 139         setAutoHorizontalScroll(true);
 140     }
 141 }
 142
 143 KTreeView::~KTreeView()
 144 {
 145 }
 146
 147 void KTreeView::setAutoHorizontalScroll(bool value)
 148 {
 149         d->autoHorizontalScroll = value;
 150 }
 151
 152 bool KTreeView::autoHorizontalScroll() const
 153 {
 154         return d->autoHorizontalScroll;
 155 }
 156
 157 void KTreeView::setSelectionModel(QItemSelectionModel *selectionModel)
 158 {
 159     QTreeView::setSelectionModel(selectionModel);
 160     connect(selectionModel,
 161             SIGNAL(selectionChanged(const QItemSelection&, const QItemSelection&)),
 162             d->startScrollTimer, SLOT(start()));
 163 }
 164
 165 void KTreeView::scrollTo(const QModelIndex& index, ScrollHint hint)
 166 {
 167     if (d->autoHorizontalScroll) {
 168         // assure that the value of the horizontal scrollbar stays on its current value,
 169         // KTreeView will adjust the value manually
 170         const int value = horizontalScrollBar()->value();
 171         QTreeView::scrollTo(index, hint);
 172         horizontalScrollBar()->setValue(value);
 173     } else {
 174         QTreeView::scrollTo(index, hint);
 175     }
 176 }
 177
 178 bool KTreeView::event(QEvent* event)
 179 {
 180     if (event->type() == QEvent::Polish) {
 181         d->connectScrollTimers();
 182     }
 183     return QTreeView::event(event);
 184 }
 185
 186 #include "ktreeview.moc"
 187 #include "ktreeview_p.moc"