1 files changed, 216 insertions, 0 deletions
diff --git a/src/charts/scroller.cpp b/src/charts/scroller.cpp
new file mode 100644
index 00000000..add8f92a
--- /dev/null
+++ b/src/charts/scroller.cpp
@@ -0,0 +1,216 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc
+** All rights reserved.
+** For any questions to Digia, please use contact form at http://qt.digia.com
+**
+** This file is part of the Qt Enterprise Charts Add-on.
+**
+** $QT_BEGIN_LICENSE$
+** Licensees holding valid Qt Enterprise licenses may use this file in
+** accordance with the Qt Enterprise License Agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.
+**
+** If you have questions regarding the use of this file, please use
+** contact form at http://qt.digia.com
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "scroller_p.h"
+#include "qlegend.h"
+#include <QGraphicsSceneMouseEvent>
+#include <QDebug>
+
+QT_CHARTS_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 = QTime::currentTime();
+        break;
+    case Scroll:
+        stopTicker();
+        m_timeStamp = QTime::currentTime();
+        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.msecsTo(QTime::currentTime()) < m_timeTresholdMax)) {
+        // Release was quick enough. Start scrolling.
+        qreal interval = 25;
+        qreal time = m_timeStamp.msecsTo(QTime::currentTime());
+        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();
+}
+
+#include "moc_scroller_p.cpp"
+
+QT_CHARTS_END_NAMESPACE