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 /* FIXME: make this portably */
  27 #include <unistd.h>
  28 #include <QGraphicsGridLayout>
  29
  30 /* TODO:
  31  * - kill the fscking timer in overshut
  32  * - bump effect when rolling (twice should be enough)
  33  * - add a scrollbar for reference
  34  * - kinetic velocity parameterized upon count of list items
  35  * - ringbuffer (minimize number of items in the QGV).
  36  * - parameterize dimensions
  37  */
  38
  39 KineticView::KineticView( QGraphicsWidget *parent )
  40     : QGraphicsWidget( parent ), mScrollVelocity( 0 ), newclick( 0 ),
  41       timerID( 0 ), overshut( 30 )
  42 {
  43     setSizePolicy( QSizePolicy::Expanding, QSizePolicy::Expanding);
  44
  45     mViewPort = new QGraphicsWidget( this );
  46     mViewPort->setSizePolicy( QSizePolicy::Expanding, QSizePolicy::Expanding );
  47     mViewPort->setFlag( QGraphicsItem::ItemClipsChildrenToShape, true);
  48     layout = new QGraphicsGridLayout( this );
  49     layout->addItem( mViewPort, 0, 0 );
  50
  51     setAcceptedMouseButtons( Qt::LeftButton );
  52 }
  53
  54 KineticView::~KineticView()
  55 {
  56     delete mWindow;
  57 }
  58
  59 void KineticView::startTimer(int interval)
  60 {
  61     timerID = QObject::startTimer( interval );
  62 }
  63 void KineticView::setWidget( QGraphicsWidget *item)
  64 {
  65     mWindow = item;
  66     mWindow->setSizePolicy( QSizePolicy::Expanding, QSizePolicy::Fixed );
  67     mWindow->setParentItem( mViewPort );
  68     mWindow->setPos( 0, 0 );
  69     mWindow->setAcceptedMouseButtons(  Qt::LeftButton );
  70
  71     update();
  72 }
  73
  74 void KineticView::bounceTimer()
  75 {
  76     int delta = -5;
  77     if ( direction == DOWN )
  78         delta = 5;
  79     cposition += delta;
  80     mWindow->setPos( 0, cposition );
  81
  82     if ( ( direction == UP ) && ( cposition < 0 ) ) {
  83         qDebug() << "Done UP bouncing.....!!!!!!!!!";
  84         direction = NONE;
  85         mScrollVelocity = 0;
  86         cposition = 0;
  87         newclick = 1;
  88         killTimer( timerID );
  89         timerID = 0;
  90     } else if ( ( direction == DOWN ) &&
  91                 ( ( cposition - overshut) > minimalPos ) ) {
  92         qDebug() << "Done DOWN bouncing.....!!!!!!!!!";
  93         direction = NONE;
  94         mScrollVelocity = 0;
  95         cposition = minimalPos + overshut;
  96         newclick = 1;
  97         killTimer( timerID );
  98         timerID = 0;
  99     }
 100
 101     qDebug() << "cposition: " << cposition;
 102 }
 103
 104 void KineticView::setScrollValue( int value )
 105 {
 106     minimalPos = -mWindow->size().height() + mViewPort->size().height() - overshut;
 107     minimalPos = qMin( overshut, minimalPos );
 108     maximumPos = mWindow->pos().y() - value;
 109
 110     cposition = qBound( minimalPos, maximumPos, overshut );
 111     mWindow->setPos( 0, cposition );
 112
 113     if ( cposition == overshut ) {
 114         qDebug() << "UPPER edge: animate overshut";
 115         mScrollVelocity = 5;
 116         direction = UP;
 117         startTimer( 20 );
 118
 119     } else if ( cposition == minimalPos ) {
 120         qDebug() << "LOWER edge: animate overshut";
 121         mScrollVelocity = 5;
 122         direction = DOWN;
 123         startTimer( 20 );
 124     } else
 125         direction = NONE;
 126 }
 127
 128 void KineticView::mousePressEvent( QGraphicsSceneMouseEvent *event )
 129 {
 130     event->accept();
 131     newclick = 1;
 132     killTimer( timerID );
 133     timerID = 0;
 134     KineticScrolling::mousePressEvent( static_cast<QGraphicsSceneMouseEvent*>(event) );
 135 }
 136
 137 void KineticView::mouseMoveEvent( QGraphicsSceneMouseEvent *event )
 138 {
 139     newclick = 0;
 140     KineticScrolling::mouseMoveEvent( static_cast<QGraphicsSceneMouseEvent*>(event) );
 141     QGraphicsWidget::mouseMoveEvent( static_cast<QGraphicsSceneMouseEvent*>(event) );
 142     setScrollValue( movement() );
 143 }
 144
 145 void KineticView::mouseReleaseEvent( QGraphicsSceneMouseEvent *event )
 146 {
 147     newclick = 0;
 148     KineticScrolling::mouseReleaseEvent(
 149     static_cast<QGraphicsSceneMouseEvent*>( event ) );
 150     mScrollVelocity = kin_movement();
 151     startTimer( 50 );
 152 }
 153
 154 void KineticView::timerEvent( QTimerEvent *event )
 155 {
 156     qDebug() << "timer......" << "direction: " << direction
 157              << "\tnewclick: " << newclick
 158              << "\tvelocity: " << mScrollVelocity
 159              << "\tcposition: " << cposition;
 160
 161     if ( newclick ) {
 162         if ( timerID )
 163             killTimer( timerID );
 164         return;
 165     }
 166
 167     if (direction == NONE ) {
 168         setScrollValue( qRound( mScrollVelocity ) );
 169
 170         mScrollVelocity *= 0.9;
 171         if ( qAbs( mScrollVelocity ) < 5.0 ) {
 172             if ( timerID ) {
 173                 killTimer( timerID );
 174             }
 175         }
 176     } else
 177         bounceTimer();
 178
 179 }