src/ktreeview.cpp

   1 /***************************************************************************
   2  *   Copyright (C) 2008 by <haraldhv (at) stud.ntnu.no>                    *
   3  *                                                                         *
   4  *   This program is free software; you can redistribute it and/or modify  *
   5  *   it under the terms of the GNU General Public License as published by  *
   6  *   the Free Software Foundation; either version 2 of the License, or     *
   7  *   (at your option) any later version.                                   *
   8  *                                                                         *
   9  *   This program is distributed in the hope that it will be useful,       *
  10  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  11  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  12  *   GNU General Public License for more details.                          *
  13  *                                                                         *
  14  *   You should have received a copy of the GNU General Public License     *
  15  *   along with this program; if not, write to the                         *
  16  *   Free Software Foundation, Inc.,                                       *
  17  *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA            *
  18  ***************************************************************************/
  19
  20 #include <KGlobalSettings>
  21
  22 #include <QDebug>
  23 #include <QScrollBar>
  24
  25 #include "ktreeview.h"
  26 #include "ktreeview_p.h"
  27
  28 KTreeView::KTreeViewPrivate::KTreeViewPrivate(KTreeView *parent)
  29         : parent(parent),
  30         autoHorizontalScroll(true),
  31         scrollTowards(0),
  32         scrollPixels(5),
  33         scrollDelay(50),
  34         leftSideMargin(30),
  35         considerDelay(500),
  36         topLeftPoint(QPoint(10,10))
  37 {
  38         Q_ASSERT(parent->verticalScrollBar());
  39
  40         considerDelayTimer.setInterval(considerDelay);
  41
  42         connect( &considerDelayTimer,
  43                         SIGNAL(timeout()),
  44                         this,
  45                         SLOT(considerAutoScroll())
  46                    );
  47
  48         connect( parent->verticalScrollBar(),
  49                         SIGNAL(rangeChanged(int, int)),
  50                         &considerDelayTimer,
  51                         SLOT(start())
  52                    );
  53
  54         connect( parent->verticalScrollBar(),
  55                         SIGNAL(valueChanged(int)),
  56                         &considerDelayTimer,
  57                         SLOT(start())
  58                    );
  59
  60         connect( parent,
  61                         SIGNAL( collapsed ( const QModelIndex &)),
  62                         &considerDelayTimer,
  63                         SLOT(start())
  64                    );
  65
  66         connect( parent,
  67                         SIGNAL( expanded ( const QModelIndex &)),
  68                         &considerDelayTimer,
  69                         SLOT(start())
  70                    );
  71
  72 }
  73
  74 void KTreeView::KTreeViewPrivate::considerAutoScroll()
  75 {
  76         qDebug() << "Considering auto scroll";
  77
  78         QModelIndex i = parent->indexAt(topLeftPoint);
  79         int smallest = parent->width();
  80
  81         while (i.isValid())
  82         {
  83                 QRect r = parent->visualRect(i);
  84                 if (r.top() > parent->height())
  85                         break;
  86
  87                 int leftSide = r.left();
  88
  89                 smallest = qMin(smallest, leftSide);
  90                 i = parent->indexBelow(i);
  91         }
  92
  93         int currentScroll = parent->horizontalScrollBar()->value();
  94
  95         setScrollTowards(smallest + currentScroll - leftSideMargin);
  96
  97         considerDelayTimer.stop();
  98
  99 }
 100
 101 void KTreeView::KTreeViewPrivate::autoScrollTimeout()
 102 {
 103
 104         Q_ASSERT(parent);
 105
 106         QScrollBar *scrollBar = parent->horizontalScrollBar();
 107         if (scrollBar == NULL)
 108         {
 109                 qDebug() << "Warning: no scrollbar present, but told to scroll.";
 110                 scrollTimer.stop();
 111                 return;
 112         }
 113
 114         int currentScroll = scrollBar->value();
 115
 116         int difference = currentScroll - scrollTowards;
 117
 118         if (qAbs(difference) < scrollPixels)
 119         {
 120                 scrollBar->setValue(scrollTowards);
 121                 scrollTimer.stop();
 122                 return;
 123         }
 124
 125         if (difference < 0)
 126         {
 127                 scrollBar->setValue(currentScroll + scrollPixels);
 128         }
 129         else
 130         {
 131                 scrollBar->setValue(currentScroll - scrollPixels);
 132         }
 133 }
 134
 135 void KTreeView::KTreeViewPrivate::setScrollTowards( int scrollTowards )
 136 {
 137         if (scrollTowards < 0)
 138                 scrollTowards = 0;
 139         this->scrollTowards = scrollTowards;
 140         scrollTimer.start(scrollDelay);
 141 }
 142
 143 //************************************************
 144
 145 KTreeView::KTreeView(QWidget *parent)
 146         : QTreeView(parent)
 147         , d(new KTreeViewPrivate(this))
 148 {
 149         /* The graphicEffectsLevel was not available in the 4.0.3 version of
 150          * the libs I was compiling with, so this is left out for now and
 151          * enabled by default...
 152          */
 153         //if (KGlobalSettings::graphicEffectsLevel() >=
 154                         //KGlobalSettings::SimpleAnimationEffects)
 155         //{
 156                 setAutoHorizontalScroll(true);
 157         //}
 158                 connect(
 159                                 &d->scrollTimer,
 160                                 SIGNAL(timeout()),
 161                                 d,
 162                                 SLOT(autoScrollTimeout())
 163                            );
 164
 165 }
 166
 167 void KTreeView::setAutoHorizontalScroll(bool value)
 168 {
 169         d->autoHorizontalScroll = value;
 170 }
 171
 172 bool KTreeView::autoHorizontalScroll( void )
 173 {
 174         return d->autoHorizontalScroll;
 175 }
 176
 177 #include "ktreeview.moc"
 178 #include "ktreeview_p.moc"