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accurate speed calculation to kinetic scrolling
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r2190:2e3db467e0a5
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1 /****************************************************************************
1 /****************************************************************************
2 **
2 **
3 ** Copyright (C) 2012 Digia Plc
3 ** Copyright (C) 2012 Digia Plc
4 ** All rights reserved.
4 ** All rights reserved.
5 ** For any questions to Digia, please use contact form at http://qt.digia.com
5 ** For any questions to Digia, please use contact form at http://qt.digia.com
6 **
6 **
7 ** This file is part of the Qt Commercial Charts Add-on.
7 ** This file is part of the Qt Commercial Charts Add-on.
8 **
8 **
9 ** $QT_BEGIN_LICENSE$
9 ** $QT_BEGIN_LICENSE$
10 ** Licensees holding valid Qt Commercial licenses may use this file in
10 ** Licensees holding valid Qt Commercial licenses may use this file in
11 ** accordance with the Qt Commercial License Agreement provided with the
11 ** accordance with the Qt Commercial License Agreement provided with the
12 ** Software or, alternatively, in accordance with the terms contained in
12 ** Software or, alternatively, in accordance with the terms contained in
13 ** a written agreement between you and Digia.
13 ** a written agreement between you and Digia.
14 **
14 **
15 ** If you have questions regarding the use of this file, please use
15 ** If you have questions regarding the use of this file, please use
16 ** contact form at http://qt.digia.com
16 ** contact form at http://qt.digia.com
17 ** $QT_END_LICENSE$
17 ** $QT_END_LICENSE$
18 **
18 **
19 ****************************************************************************/
19 ****************************************************************************/
20
20
21 #include "scroller_p.h"
21 #include "scroller_p.h"
22 #include "qlegend.h"
22 #include "qlegend.h"
23 #include <QGraphicsSceneMouseEvent>
23 #include <QGraphicsSceneMouseEvent>
24 #include <QDebug>
24 #include <QDebug>
25
25
26 QTCOMMERCIALCHART_BEGIN_NAMESPACE
26 QTCOMMERCIALCHART_BEGIN_NAMESPACE
27
27
28 Scroller::Scroller()
28 Scroller::Scroller()
29 : m_ticker(this),
29 : m_ticker(this),
30 m_timeTresholdMin(50),
30 m_timeTresholdMin(50),
31 m_timeTresholdMax(300),
31 m_timeTresholdMax(300),
32 m_state(Idle)
32 m_state(Idle)
33 {
33 {
34
34
35 }
35 }
36
36
37 Scroller::~Scroller()
37 Scroller::~Scroller()
38 {
38 {
39 }
39 }
40
40
41 void Scroller::move(const QPointF &delta)
41 void Scroller::move(const QPointF &delta)
42 {
42 {
43 switch (m_state) {
43 switch (m_state) {
44 case Idle:
44 case Idle:
45 m_timeStamp = QTime::currentTime();
45 m_timeStamp = QTime::currentTime();
46 m_state = Move;
46 m_state = Move;
47 break;
47 break;
48 case Scroll:
48 case Scroll:
49 stopTicker();
49 stopTicker();
50 m_timeStamp = QTime::currentTime();
50 m_timeStamp = QTime::currentTime();
51 m_state = Move;
51 m_state = Move;
52 break;
52 break;
53 default:
53 default:
54 break;
54 break;
55 }
55 }
56 setOffset(offset() - delta);
56 setOffset(offset() - delta);
57 }
57 }
58
58
59 void Scroller::release(const QPointF &delta)
59 void Scroller::release(const QPointF &delta)
60 {
60 {
61 // Starts scrolling, if at least m_timeTresholdMin msecs has gone since timestamp
61 // Starts scrolling, if at least m_timeTresholdMin msecs has gone since timestamp
62 // current time is no more than m_timeTresholdMax from timestamp
62 // current time is no more than m_timeTresholdMax from timestamp
63
63
64 if ((m_timeStamp.elapsed() > m_timeTresholdMin) && (m_timeStamp.msecsTo(QTime::currentTime()) < m_timeTresholdMax)) {
64 if ((m_timeStamp.elapsed() > m_timeTresholdMin) && (m_timeStamp.msecsTo(QTime::currentTime()) < m_timeTresholdMax)) {
65 // Release was quick enough. Start scrolling.
65 // Release was quick enough. Start scrolling.
66 // Magic number is to make scroll bit slower (the resolution of screen may affect this)
66 qreal interval = 25;
67 m_speed = delta / 5;
67 qreal time = m_timeStamp.msecsTo(QTime::currentTime());
68 if (qFuzzyIsNull(time))
69 m_speed = delta / 5;
70 else
71 m_speed = delta * interval / time;
68
72
69 qreal fraction = qMax(qAbs(m_speed.x()), qAbs(m_speed.y()));
73 qreal fraction = qMax(qAbs(m_speed.x()), qAbs(m_speed.y()));
70
74
71 if (!qFuzzyIsNull(fraction)) {
75 if (!qFuzzyIsNull(fraction)) {
72 m_fraction.setX(qAbs(m_speed.x() / fraction));
76 m_fraction.setX(qAbs(m_speed.x() / fraction));
73 m_fraction.setY(qAbs(m_speed.y() / fraction));
77 m_fraction.setY(qAbs(m_speed.y() / fraction));
74 } else {
78 } else {
75 m_fraction.setX(1);
79 m_fraction.setX(1);
76 m_fraction.setY(1);
80 m_fraction.setY(1);
77 }
81 }
78 startTicker(25);
82 startTicker(interval);
79 m_state = Scroll;
83 m_state = Scroll;
80 } else {
84 } else {
81 stopTicker(); // Stop ticker, if one is running.
85 stopTicker(); // Stop ticker, if one is running.
82 m_state = Idle;
86 m_state = Idle;
83 }
87 }
84 }
88 }
85
89
86 void Scroller::startTicker(int interval)
90 void Scroller::startTicker(int interval)
87 {
91 {
88 m_state = Scroll;
92 m_state = Scroll;
89 m_ticker.start(interval);
93 m_ticker.start(interval);
90 }
94 }
91
95
92 void Scroller::stopTicker()
96 void Scroller::stopTicker()
93 {
97 {
94 m_state = Idle;
98 m_state = Idle;
95 m_ticker.stop();
99 m_ticker.stop();
96 }
100 }
97
101
98 void Scroller::scrollTick()
102 void Scroller::scrollTick()
99 {
103 {
100 switch (m_state) {
104 switch (m_state) {
101 case Scroll:
105 case Scroll:
102 lowerSpeed(m_speed);
106 lowerSpeed(m_speed);
103 setOffset(offset() - m_speed);
107 setOffset(offset() - m_speed);
104 if (m_speed == QPointF(0, 0)) {
108 if (m_speed == QPointF(0, 0)) {
105 m_state = Idle;
109 m_state = Idle;
106 m_ticker.stop();
110 m_ticker.stop();
107 }
111 }
108 break;
112 break;
109 case Idle:
113 case Idle:
110 case Move:
114 case Move:
111 qWarning() << __FUNCTION__ << "Scroller unexpected state" << m_state;
115 qWarning() << __FUNCTION__ << "Scroller unexpected state" << m_state;
112 m_ticker.stop();
116 m_ticker.stop();
113 m_state = Idle;
117 m_state = Idle;
114 break;
118 break;
115 }
119 }
116 }
120 }
117
121
118 void Scroller::lowerSpeed(QPointF &speed, qreal maxSpeed)
122 void Scroller::lowerSpeed(QPointF &speed, qreal maxSpeed)
119 {
123 {
120 qreal x = qBound(-maxSpeed, speed.x(), maxSpeed);
124 qreal x = qBound(-maxSpeed, speed.x(), maxSpeed);
121 qreal y = qBound(-maxSpeed, speed.y(), maxSpeed);
125 qreal y = qBound(-maxSpeed, speed.y(), maxSpeed);
122
126
123 x = (x == 0) ? x :
127 x = (x == 0) ? x :
124 (x > 0) ? qMax(qreal(0), x - m_fraction.x()) : qMin(qreal(0), x + m_fraction.x());
128 (x > 0) ? qMax(qreal(0), x - m_fraction.x()) : qMin(qreal(0), x + m_fraction.x());
125 y = (y == 0) ? y :
129 y = (y == 0) ? y :
126 (y > 0) ? qMax(qreal(0), y - m_fraction.y()) : qMin(qreal(0), y + m_fraction.y());
130 (y > 0) ? qMax(qreal(0), y - m_fraction.y()) : qMin(qreal(0), y + m_fraction.y());
127 speed.setX(x);
131 speed.setX(x);
128 speed.setY(y);
132 speed.setY(y);
129 }
133 }
130
134
131 /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
135 /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
132
136
133 ScrollTicker::ScrollTicker(Scroller *scroller, QObject *parent)
137 ScrollTicker::ScrollTicker(Scroller *scroller, QObject *parent)
134 : QObject(parent),
138 : QObject(parent),
135 m_scroller(scroller)
139 m_scroller(scroller)
136 {
140 {
137
141
138 }
142 }
139
143
140 void ScrollTicker::start(int interval)
144 void ScrollTicker::start(int interval)
141 {
145 {
142 if (!m_timer.isActive())
146 if (!m_timer.isActive())
143 m_timer.start(interval, this);
147 m_timer.start(interval, this);
144 }
148 }
145
149
146 void ScrollTicker::stop()
150 void ScrollTicker::stop()
147 {
151 {
148 m_timer.stop();
152 m_timer.stop();
149 }
153 }
150
154
151 void ScrollTicker::timerEvent(QTimerEvent *event)
155 void ScrollTicker::timerEvent(QTimerEvent *event)
152 {
156 {
153 Q_UNUSED(event);
157 Q_UNUSED(event);
154 m_scroller->scrollTick();
158 m_scroller->scrollTick();
155 }
159 }
156
160
157 #include "moc_scroller_p.cpp"
161 #include "moc_scroller_p.cpp"
158
162
159 QTCOMMERCIALCHART_END_NAMESPACE
163 QTCOMMERCIALCHART_END_NAMESPACE
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