kineticview.cpp

   1 /////////////////////////////////////////////////////////////////////////
   2 // kineticview.cpp                                                     //
   3 //                                                                     //
   4 // Copyright(C) 2009 Igor Trindade Oliveira <igor.oliveira@indt.org.br>//
   5 // Copyright(C) 2009 Adenilson Cavalcanti <adenilson.silva@idnt.org.br>//
   6 //                                                                     //
   7 // This library is free software; you can redistribute it and/or       //
   8 // modify it under the terms of the GNU Lesser General Public          //
   9 // License as published by the Free Software Foundation; either        //
  10 // version 2.1 of the License, or (at your option) any later version.  //
  11 //                                                                     //
  12 // This library is distributed in the hope that it will be useful,     //
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of      //
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU   //
  15 // Lesser General Public License for more details.                     //
  16 //                                                                     //
  17 // You should have received a copy of the GNU Lesser General Public    //
  18 // License along with this library; if not, write to the Free Software //
  19 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA       //
  20 // 02110-1301  USA                                                     //
  21 /////////////////////////////////////////////////////////////////////////
  22 #include "kineticview.h"
  23
  24 #include <QObject>
  25 #include <QDebug>
  26 #include <QGraphicsGridLayout>
  27
  28 /* TODO:
  29  * - kill the fscking timer in overshut
  30  * - bump effect when rolling (twice should be enough)
  31  * - add a scrollbar for reference
  32  * - kinetic velocity parameterized upon count of list items
  33  * - ringbuffer (minimize number of items in the QGV).
  34  * - parameterize dimensions
  35  */
  36
  37 KineticView::KineticView( QGraphicsWidget *parent )
  38     : QGraphicsWidget( parent ), mScrollVelocity( 0 ),
  39       timerID( 0 ), overshut( 30 )
  40 {
  41     setSizePolicy( QSizePolicy::Expanding, QSizePolicy::Expanding);
  42
  43     mViewPort = new QGraphicsWidget( this );
  44     mViewPort->setSizePolicy( QSizePolicy::Expanding, QSizePolicy::Expanding );
  45     mViewPort->setFlag( QGraphicsItem::ItemClipsChildrenToShape, true);
  46     layout = new QGraphicsGridLayout( this );
  47     layout->addItem( mViewPort, 0, 0 );
  48
  49     setAcceptedMouseButtons( Qt::LeftButton );
  50 }
  51
  52 KineticView::~KineticView()
  53 {
  54     delete mWindow;
  55 }
  56
  57 void KineticView::startTimer(int interval)
  58 {
  59     timerID = QObject::startTimer( interval );
  60 }
  61 void KineticView::setWidget( QGraphicsWidget *item)
  62 {
  63     mWindow = item;
  64     mWindow->setSizePolicy( QSizePolicy::Expanding, QSizePolicy::Fixed );
  65     mWindow->setParentItem( mViewPort );
  66     mWindow->setPos( 0, 0 );
  67     mWindow->setAcceptedMouseButtons(  Qt::LeftButton );
  68
  69     update();
  70 }
  71
  72 void KineticView::bounceTimer()
  73 {
  74     int delta = -5;
  75     if ( direction == DOWN )
  76         delta = 5;
  77     cposition += delta;
  78     mWindow->setPos( 0, cposition );
  79
  80     if ( ( direction == UP ) && ( cposition < 0 ) ) {
  81         qDebug() << "Done UP bouncing.....!!!!!!!!!";
  82         direction = NONE;
  83         mScrollVelocity = 0;
  84         cposition = 0;
  85         killTimer( timerID );
  86         timerID = 0;
  87     } else if ( ( direction == DOWN ) &&
  88                 ( ( cposition - overshut) > minimalPos ) ) {
  89         qDebug() << "Done DOWN bouncing.....!!!!!!!!!";
  90         direction = NONE;
  91         mScrollVelocity = 0;
  92         cposition = minimalPos + overshut;
  93         killTimer( timerID );
  94         timerID = 0;
  95     }
  96
  97     qDebug() << "cposition: " << cposition;
  98 }
  99
 100 void KineticView::setScrollValue( int value )
 101 {
 102     minimalPos = -mWindow->size().height() + mViewPort->size().height() - overshut;
 103     minimalPos = qMin( overshut, minimalPos );
 104     maximumPos = mWindow->pos().y() - value;
 105
 106     cposition = qBound( minimalPos, maximumPos, overshut );
 107     mWindow->setPos( 0, cposition );
 108
 109     if ( cposition == overshut ) {
 110         qDebug() << "UPPER edge: animate overshut";
 111         mScrollVelocity = 5;
 112         direction = UP;
 113         startTimer( 20 );
 114
 115     } else if ( cposition == minimalPos ) {
 116         qDebug() << "LOWER edge: animate overshut";
 117         mScrollVelocity = 5;
 118         direction = DOWN;
 119         startTimer( 20 );
 120     } else
 121         direction = NONE;
 122 }
 123
 124 void KineticView::mousePressEvent( QGraphicsSceneMouseEvent *event )
 125 {
 126     event->accept();
 127     killTimer( timerID );
 128     timerID = 0;
 129     KineticScrolling::mousePressEvent( static_cast<QGraphicsSceneMouseEvent*>(event) );
 130 }
 131
 132 void KineticView::mouseMoveEvent( QGraphicsSceneMouseEvent *event )
 133 {
 134     KineticScrolling::mouseMoveEvent( static_cast<QGraphicsSceneMouseEvent*>(event) );
 135     QGraphicsWidget::mouseMoveEvent( static_cast<QGraphicsSceneMouseEvent*>(event) );
 136     setScrollValue( movement() );
 137 }
 138
 139 void KineticView::mouseReleaseEvent( QGraphicsSceneMouseEvent *event )
 140 {
 141     KineticScrolling::mouseReleaseEvent(
 142     static_cast<QGraphicsSceneMouseEvent*>( event ) );
 143     mScrollVelocity = kin_movement();
 144     startTimer( 50 );
 145 }
 146
 147 void KineticView::timerEvent( QTimerEvent *event )
 148 {
 149     qDebug() << "timer......" << "direction: " << direction
 150              << "\tvelocity: " << mScrollVelocity
 151              << "\tcposition: " << cposition;
 152
 153     if (direction == NONE ) {
 154         setScrollValue( qRound( mScrollVelocity ) );
 155
 156         mScrollVelocity *= 0.9;
 157         if ( qAbs( mScrollVelocity ) < 5.0 ) {
 158             if ( timerID ) {
 159                 killTimer( timerID );
 160             }
 161         }
 162     } else
 163         bounceTimer();
 164
 165 }