Revision control
++ // Copyright (C) 2016 The Qt Company Ltd.
++ // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
++
++ #include <private/scroller_p.h>
++ #include <QtCharts/QLegend>
++ #include <QtWidgets/QGraphicsSceneMouseEvent>
++ #include <QtCore/QDebug>
++
++ QT_BEGIN_NAMESPACE
++
++ Scroller::Scroller()
++ : m_ticker(this),
++ m_timeTresholdMin(50),
++ m_timeTresholdMax(300),
++ m_state(Idle),
++ m_treshold(10)
++ {
++
++ }
++
++ Scroller::~Scroller()
++ {
++ }
++
++ void Scroller::move(const QPointF &delta)
++ {
++ switch (m_state) {
++ case Pressed:
++ m_timeStamp.start();
++ break;
++ case Scroll:
++ stopTicker();
++ m_timeStamp.start();
++ break;
++ default:
++ break;
++ }
++ setOffset(offset() - delta);
++ }
++
++ void Scroller::scrollTo(const QPointF &delta)
++ {
++ // Starts scrolling, if at least m_timeTresholdMin msecs has gone since timestamp
++ // current time is no more than m_timeTresholdMax from timestamp
++
++ if ((m_timeStamp.elapsed() > m_timeTresholdMin) && (m_timeStamp.elapsed() < m_timeTresholdMax)) {
++ // Release was quick enough. Start scrolling.
++ qreal interval = 25;
++ qreal time = m_timeStamp.elapsed();
++ if (qFuzzyCompare(time, 0)) {
++ m_speed = delta / 5;
++ } else {
++ m_speed = delta * interval / time;
++ }
++
++ qreal fraction = qMax(qAbs(m_speed.x()), qAbs(m_speed.y()));
++
++ if (!qFuzzyCompare(fraction, 0)) {
++ m_fraction.setX(qAbs(m_speed.x() / fraction));
++ m_fraction.setY(qAbs(m_speed.y() / fraction));
++ } else {
++ m_fraction.setX(1);
++ m_fraction.setY(1);
++ }
++ startTicker(interval);
++ } else {
++ stopTicker(); // Stop ticker, if one is running.
++ }
++ }
++
++ void Scroller::handleMousePressEvent(QGraphicsSceneMouseEvent *event)
++ {
++ stopTicker();
++ m_pressPos = event->screenPos();
++ m_lastPos = m_pressPos;
++ m_state = Pressed;
++ event->accept();
++ }
++
++ void Scroller::handleMouseMoveEvent(QGraphicsSceneMouseEvent *event)
++ {
++ QPointF delta = event->screenPos() - m_lastPos;
++
++ switch (m_state) {
++ case Pressed: {
++ // calculate treshold. If enough, change to move state and send out move deltas.
++ if (qAbs(delta.x()) > m_treshold || qAbs(delta.y()) > m_treshold) {
++ m_lastPos = event->screenPos();
++ move(delta);
++ m_state = Move;
++ }
++ event->accept();
++ break;
++ }
++ case Move: {
++ m_lastPos = event->screenPos();
++ move(delta);
++ event->accept();
++ break;
++ }
++ case Idle:
++ default: {
++ event->ignore();
++ break;
++ }
++ }
++ }
++
++ void Scroller::handleMouseReleaseEvent(QGraphicsSceneMouseEvent *event)
++ {
++ switch (m_state) {
++ case Move:
++ {
++ scrollTo(m_lastPos - m_pressPos);
++ event->accept();
++ break;
++ }
++ default:
++ {
++ m_state = Idle;
++ event->ignore();
++ break;
++ }
++ }
++ }
++
++ void Scroller::startTicker(int interval)
++ {
++ m_state = Scroll;
++ m_ticker.start(interval);
++ }
++
++ void Scroller::stopTicker()
++ {
++ m_state = Idle;
++ m_ticker.stop();
++ }
++
++ void Scroller::scrollTick()
++ {
++ switch (m_state) {
++ case Scroll:
++ lowerSpeed(m_speed);
++ setOffset(offset() - m_speed);
++ if (m_speed == QPointF(0, 0)) {
++ m_state = Idle;
++ m_ticker.stop();
++ }
++ break;
++ default:
++ qWarning() << __FUNCTION__ << "Scroller unexpected state" << m_state;
++ m_ticker.stop();
++ m_state = Idle;
++ break;
++ }
++ }
++
++ void Scroller::lowerSpeed(QPointF &speed, qreal maxSpeed)
++ {
++ qreal x = qBound(-maxSpeed, speed.x(), maxSpeed);
++ qreal y = qBound(-maxSpeed, speed.y(), maxSpeed);
++
++ x = (x == 0) ? x :
++ (x > 0) ? qMax(qreal(0), x - m_fraction.x()) : qMin(qreal(0), x + m_fraction.x());
++ y = (y == 0) ? y :
++ (y > 0) ? qMax(qreal(0), y - m_fraction.y()) : qMin(qreal(0), y + m_fraction.y());
++ speed.setX(x);
++ speed.setY(y);
++ }
++
++ /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
++
++ ScrollTicker::ScrollTicker(Scroller *scroller, QObject *parent)
++ : QObject(parent),
++ m_scroller(scroller)
++ {
++
++ }
++
++ void ScrollTicker::start(int interval)
++ {
++ if (!m_timer.isActive())
++ m_timer.start(interval, this);
++ }
++
++ void ScrollTicker::stop()
++ {
++ m_timer.stop();
++ }
++
++ void ScrollTicker::timerEvent(QTimerEvent *event)
++ {
++ Q_UNUSED(event);
++ m_scroller->scrollTick();
++ }
++
++ QT_END_NAMESPACE
++
++ #include "moc_scroller_p.cpp"