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