305 lines
8.2 KiB
C++
305 lines
8.2 KiB
C++
/////////////////////////////////////////////////////////////////////////
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// kineticscroll.cpp //
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// //
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// Copyright(C) 2009 Igor Trindade Oliveira <igor.oliveira@indt.org.br>//
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// Copyright(C) 2009 Adenilson Cavalcanti <adenilson.silva@idnt.org.br>//
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// //
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// This library is free software; you can redistribute it and/or //
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// modify it under the terms of the GNU Lesser General Public //
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// License as published by the Free Software Foundation; either //
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// version 2.1 of the License, or (at your option) any later version. //
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// //
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// This library is distributed in the hope that it will be useful, //
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// but WITHOUT ANY WARRANTY; without even the implied warranty of //
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU //
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// Lesser General Public License for more details. //
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// //
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// You should have received a copy of the GNU Lesser General Public //
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// License along with this library; if not, write to the Free Software //
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// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA //
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// 02110-1301 USA //
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/////////////////////////////////////////////////////////////////////////
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#include <QtCore/qglobal.h>
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#include <QtCore/qmetatype.h>
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#include <QGraphicsSceneMouseEvent>
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#include <QTime>
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#include <QDebug>
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#include <QGraphicsWidget>
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#include "kineticscroll_p.h"
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/* TODO:
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* - write a factory to animation/state object
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* - move timer based code to an implementation of the factory
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* - write another implementation using QPropertyAnimation Qt 4.6
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* - generalize code concerning viewport and other parameters
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* - swap the 'magic numbers' for consts
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* - consider if direct access to control state/velocity variables should
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* be done directly or using functions
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* - implement horizontal scrolling (simultaneously with vertical)
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*/
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namespace Plasma
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{
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class KineticScrollingPrivate
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{
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public:
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KineticScrollingPrivate(): mScrollVelocity(0), timerID(0),
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overshoot(40), bounceFlag(0)
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{ }
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void count()
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{
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t = QTime::currentTime();
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t.start();
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}
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unsigned int elapsed()
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{
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return t.restart();
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}
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void verticalScroll(int value)
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{
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widget->setPos(QPoint(0, -value*10));
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}
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void horizontalScroll(int value)
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{
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widget->setPos(QPoint(-value*10, 0));
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}
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unsigned int timeDelta;
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qreal scrollVelocity;
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int movement;
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int kinMovement;
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qreal mScrollVelocity;
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enum { None, Up, Down };
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int timerID, overshoot, cposition, direction, minimalPos, maximumPos;
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char bounceFlag;
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QGraphicsWidget *widget;
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QGraphicsWidget *scrollingWidget;
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protected:
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QTime t;
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};
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KineticScrolling::KineticScrolling(): d(0)
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{
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d = new KineticScrollingPrivate;
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}
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KineticScrolling::~KineticScrolling()
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{
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delete d;
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}
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int KineticScrolling::movement() const
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{
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return d->movement;
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}
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int KineticScrolling::kinMovement() const
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{
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return d->kinMovement;
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}
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qreal KineticScrolling::duration() const
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{
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return d->timeDelta;
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}
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void KineticScrolling::mousePressEvent(QGraphicsSceneMouseEvent *event)
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{
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doneOvershoot();
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Q_UNUSED(event);
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d->count();
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d->scrollVelocity = 0;
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d->movement = 0;
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d->kinMovement = 0;
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}
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void KineticScrolling::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
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{
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int temp = event->lastPos().y() - event->pos().y();
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if (temp) {
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d->movement = temp;
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d->kinMovement += temp;
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}
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/* After */
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setKineticScrollValue(movement());
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}
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void KineticScrolling::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
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{
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d->timeDelta = d->elapsed();
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int temp = event->lastPos().y() - event->pos().y();
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if (temp)
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d->kinMovement += temp;
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if (d->timeDelta > 600) {
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if (d->kinMovement > 0)
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d->kinMovement = 3;
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else
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d->kinMovement = -3;
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}
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/* The after */
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if (d->cposition > 0) {
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d->direction = KineticScrollingPrivate::Up;
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} else if (abs(d->cposition) >
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abs(d->scrollingWidget->size().height() - d->widget->size().height())) {
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d->direction = KineticScrollingPrivate::Down;
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} else {
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d->direction = KineticScrollingPrivate::None;
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d->mScrollVelocity = kinMovement();
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startAnimationTimer(30);
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return;
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}
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d->mScrollVelocity = 5;
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killTimer(d->timerID);
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startAnimationTimer(50);
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}
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void KineticScrolling::wheelReleaseEvent(QGraphicsSceneWheelEvent *event)
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{
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mousePressEvent(0);
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/* Core */
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d->timeDelta = d->elapsed();
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int temp = event->delta();
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temp *= -0.5;
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d->kinMovement += temp;
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/* After */
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d->mScrollVelocity = kinMovement();
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startAnimationTimer(30);
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}
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void KineticScrolling::startAnimationTimer(int interval)
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{
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if (d->timerID) {
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killTimer(d->timerID);
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d->timerID = 0;
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}
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d->timerID = QObject::startTimer(interval);
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}
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void KineticScrolling::timerEvent(QTimerEvent *event)
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{
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Q_UNUSED(event);
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if (d->direction == KineticScrollingPrivate::None) {
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d->mScrollVelocity *= 0.9;
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if (qAbs(d->mScrollVelocity) < 5.0) {
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if (d->timerID)
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killTimer(d->timerID);
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}
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setKineticScrollValue(qRound(d->mScrollVelocity));
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} else {
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if ((d->timerID != 0) && (d->direction != KineticScrollingPrivate::None)) {
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bounceTimer();
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}
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}
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}
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void KineticScrolling::setKineticScrollValue(int value)
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{
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d->minimalPos = (-(d->widget->size().height())) + d->scrollingWidget->size().height()
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-(d->overshoot);
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d->minimalPos = qMin(d->overshoot, d->minimalPos);
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d->maximumPos = d->widget->pos().y() - value;
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d->cposition = qBound(d->minimalPos, d->maximumPos, d->overshoot);
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d->widget->setPos(0, d->cposition);
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if (d->cposition == d->overshoot) {
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d->direction = KineticScrollingPrivate::Up;
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killTimer(d->timerID);
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d->mScrollVelocity = 5;
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startAnimationTimer(30);
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} else if (d->cposition == d->minimalPos) {
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d->direction = KineticScrollingPrivate::Down;
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killTimer(d->timerID);
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d->mScrollVelocity = 5;
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startAnimationTimer(30);
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} else
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d->direction = KineticScrollingPrivate::None;
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}
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void KineticScrolling::bounceTimer()
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{
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int delta = 5;
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if ((d->direction == KineticScrollingPrivate::Up) && (d->bounceFlag == 0))
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delta = -5;
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else if ((d->direction == KineticScrollingPrivate::Up) && (d->bounceFlag == 1))
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delta = -2;
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else if ((d->direction == KineticScrollingPrivate::Down) && (d->bounceFlag == 0))
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delta = 5;
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else if ((d->direction == KineticScrollingPrivate::Down) && (d->bounceFlag == 1))
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delta = 2;
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d->cposition += delta;
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d->widget->setPos(0, d->cposition);
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if ((d->direction == KineticScrollingPrivate::Up) && (d->cposition < 0)) {
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if (!d->bounceFlag) {
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d->cposition = d->overshoot/4;
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d->bounceFlag = 1;
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d->widget->setPos(0, d->cposition);
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return;
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} else {
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d->bounceFlag = 0;
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d->cposition = 0;
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doneOvershoot() ;
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}
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} else if ((d->direction == KineticScrollingPrivate::Down) &&
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((d->cposition - d->overshoot) > d->minimalPos)) {
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if (!d->bounceFlag) {
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d->cposition = d->minimalPos + d->overshoot/4;
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d->bounceFlag = 1;
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d->widget->setPos(0, d->cposition);
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return;
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} else {
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d->bounceFlag = 0;
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d->cposition = d->minimalPos + d->overshoot;
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doneOvershoot();
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}
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}
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}
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void KineticScrolling::doneOvershoot(void)
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{
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d->direction = KineticScrollingPrivate::None;
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d->mScrollVelocity = 0;
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killTimer(d->timerID);
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d->timerID = 0;
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}
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void KineticScrolling::setWidgets(QGraphicsWidget *widget,
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QGraphicsWidget *scrolling)
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{
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d->widget = widget;
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d->scrollingWidget = scrolling;
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}
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} // namespace Plasma
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