qt5base-lts/examples/embedded/flickable/flickable.cpp
Jason McDonald 5635823e17 Remove "All rights reserved" line from license headers.
As in the past, to avoid rewriting various autotests that contain
line-number information, an extra blank line has been inserted at the
end of the license text to ensure that this commit does not change the
total number of lines in the license header.

Change-Id: I311e001373776812699d6efc045b5f742890c689
Reviewed-by: Rohan McGovern <rohan.mcgovern@nokia.com>
2012-01-30 03:54:59 +01:00

285 lines
7.1 KiB
C++

/****************************************************************************
**
** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/
**
** This file is part of the demonstration applications of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** GNU Lesser General Public License Usage
** This file may be used under the terms of the GNU Lesser General Public
** License version 2.1 as published by the Free Software Foundation and
** appearing in the file LICENSE.LGPL included in the packaging of this
** file. Please review the following information to ensure the GNU Lesser
** General Public License version 2.1 requirements will be met:
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights. These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU General
** Public License version 3.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of this
** file. Please review the following information to ensure the GNU General
** Public License version 3.0 requirements will be met:
** http://www.gnu.org/copyleft/gpl.html.
**
** Other Usage
** Alternatively, this file may be used in accordance with the terms and
** conditions contained in a signed written agreement between you and Nokia.
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "flickable.h"
#include <QtCore>
#include <QtWidgets>
class FlickableTicker: QObject
{
public:
FlickableTicker(Flickable *scroller) {
m_scroller = scroller;
}
void start(int interval) {
if (!m_timer.isActive())
m_timer.start(interval, this);
}
void stop() {
m_timer.stop();
}
protected:
void timerEvent(QTimerEvent *event) {
Q_UNUSED(event);
m_scroller->tick();
}
private:
Flickable *m_scroller;
QBasicTimer m_timer;
};
class FlickablePrivate
{
public:
typedef enum {
Steady,
Pressed,
ManualScroll,
AutoScroll,
Stop
} State;
State state;
int threshold;
QPoint pressPos;
QPoint offset;
QPoint delta;
QPoint speed;
FlickableTicker *ticker;
QTime timeStamp;
QWidget *target;
QList<QEvent*> ignoreList;
};
Flickable::Flickable()
{
d = new FlickablePrivate;
d->state = FlickablePrivate::Steady;
d->threshold = 10;
d->ticker = new FlickableTicker(this);
d->timeStamp = QTime::currentTime();
d->target = 0;
}
Flickable::~Flickable()
{
delete d;
}
void Flickable::setThreshold(int th)
{
if (th >= 0)
d->threshold = th;
}
int Flickable::threshold() const
{
return d->threshold;
}
void Flickable::setAcceptMouseClick(QWidget *target)
{
d->target = target;
}
static QPoint deaccelerate(const QPoint &speed, int a = 1, int max = 64)
{
int x = qBound(-max, speed.x(), max);
int y = qBound(-max, speed.y(), max);
x = (x == 0) ? x : (x > 0) ? qMax(0, x - a) : qMin(0, x + a);
y = (y == 0) ? y : (y > 0) ? qMax(0, y - a) : qMin(0, y + a);
return QPoint(x, y);
}
void Flickable::handleMousePress(QMouseEvent *event)
{
event->ignore();
if (event->button() != Qt::LeftButton)
return;
if (d->ignoreList.removeAll(event))
return;
switch (d->state) {
case FlickablePrivate::Steady:
event->accept();
d->state = FlickablePrivate::Pressed;
d->pressPos = event->pos();
break;
case FlickablePrivate::AutoScroll:
event->accept();
d->state = FlickablePrivate::Stop;
d->speed = QPoint(0, 0);
d->pressPos = event->pos();
d->offset = scrollOffset();
d->ticker->stop();
break;
default:
break;
}
}
void Flickable::handleMouseRelease(QMouseEvent *event)
{
event->ignore();
if (event->button() != Qt::LeftButton)
return;
if (d->ignoreList.removeAll(event))
return;
QPoint delta;
switch (d->state) {
case FlickablePrivate::Pressed:
event->accept();
d->state = FlickablePrivate::Steady;
if (d->target) {
QMouseEvent *event1 = new QMouseEvent(QEvent::MouseButtonPress,
d->pressPos, Qt::LeftButton,
Qt::LeftButton, Qt::NoModifier);
QMouseEvent *event2 = new QMouseEvent(*event);
d->ignoreList << event1;
d->ignoreList << event2;
QApplication::postEvent(d->target, event1);
QApplication::postEvent(d->target, event2);
}
break;
case FlickablePrivate::ManualScroll:
event->accept();
delta = event->pos() - d->pressPos;
if (d->timeStamp.elapsed() > 100) {
d->timeStamp = QTime::currentTime();
d->speed = delta - d->delta;
d->delta = delta;
}
d->offset = scrollOffset();
d->pressPos = event->pos();
if (d->speed == QPoint(0, 0)) {
d->state = FlickablePrivate::Steady;
} else {
d->speed /= 4;
d->state = FlickablePrivate::AutoScroll;
d->ticker->start(20);
}
break;
case FlickablePrivate::Stop:
event->accept();
d->state = FlickablePrivate::Steady;
d->offset = scrollOffset();
break;
default:
break;
}
}
void Flickable::handleMouseMove(QMouseEvent *event)
{
event->ignore();
if (!(event->buttons() & Qt::LeftButton))
return;
if (d->ignoreList.removeAll(event))
return;
QPoint delta;
switch (d->state) {
case FlickablePrivate::Pressed:
case FlickablePrivate::Stop:
delta = event->pos() - d->pressPos;
if (delta.x() > d->threshold || delta.x() < -d->threshold ||
delta.y() > d->threshold || delta.y() < -d->threshold) {
d->timeStamp = QTime::currentTime();
d->state = FlickablePrivate::ManualScroll;
d->delta = QPoint(0, 0);
d->pressPos = event->pos();
event->accept();
}
break;
case FlickablePrivate::ManualScroll:
event->accept();
delta = event->pos() - d->pressPos;
setScrollOffset(d->offset - delta);
if (d->timeStamp.elapsed() > 100) {
d->timeStamp = QTime::currentTime();
d->speed = delta - d->delta;
d->delta = delta;
}
break;
default:
break;
}
}
void Flickable::tick()
{
if (d->state == FlickablePrivate:: AutoScroll) {
d->speed = deaccelerate(d->speed);
setScrollOffset(d->offset - d->speed);
d->offset = scrollOffset();
if (d->speed == QPoint(0, 0)) {
d->state = FlickablePrivate::Steady;
d->ticker->stop();
}
} else {
d->ticker->stop();
}
}