1/****************************************************************************
2**
3** Copyright (C) 2016 The Qt Company Ltd.
4** Contact: https://www.qt.io/licensing/
5**
6** This file is part of the QtWidgets module of the Qt Toolkit.
7**
8** $QT_BEGIN_LICENSE:LGPL$
9** Commercial License Usage
10** Licensees holding valid commercial Qt licenses may use this file in
11** accordance with the commercial license agreement provided with the
12** Software or, alternatively, in accordance with the terms contained in
13** a written agreement between you and The Qt Company. For licensing terms
14** and conditions see https://www.qt.io/terms-conditions. For further
15** information use the contact form at https://www.qt.io/contact-us.
16**
17** GNU Lesser General Public License Usage
18** Alternatively, this file may be used under the terms of the GNU Lesser
19** General Public License version 3 as published by the Free Software
20** Foundation and appearing in the file LICENSE.LGPL3 included in the
21** packaging of this file. Please review the following information to
22** ensure the GNU Lesser General Public License version 3 requirements
23** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
24**
25** GNU General Public License Usage
26** Alternatively, this file may be used under the terms of the GNU
27** General Public License version 2.0 or (at your option) the GNU General
28** Public license version 3 or any later version approved by the KDE Free
29** Qt Foundation. The licenses are as published by the Free Software
30** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
31** included in the packaging of this file. Please review the following
32** information to ensure the GNU General Public License requirements will
33** be met: https://www.gnu.org/licenses/gpl-2.0.html and
34** https://www.gnu.org/licenses/gpl-3.0.html.
35**
36** $QT_END_LICENSE$
37**
38****************************************************************************/
39
40#ifndef QSCROLLER_P_H
41#define QSCROLLER_P_H
42
43//
44// W A R N I N G
45// -------------
46//
47// This file is not part of the Qt API. It exists purely as an
48// implementation detail. This header file may change from version to
49// version without notice, or even be removed.
50//
51// We mean it.
52//
53
54#include <QtWidgets/private/qtwidgetsglobal_p.h>
55#include <QObject>
56#include <QPointer>
57#include <QQueue>
58#include <QSet>
59#include <QEasingCurve>
60#include <QElapsedTimer>
61#include <QSizeF>
62#include <QPointF>
63#include <QRectF>
64#include <qscroller.h>
65#include <qscrollerproperties.h>
66#include <private/qscrollerproperties_p.h>
67#if QT_CONFIG(animation)
68#include <QAbstractAnimation>
69#endif
70
71QT_BEGIN_NAMESPACE
72
73#ifndef QT_NO_GESTURES
74class QFlickGestureRecognizer;
75#endif
76
77#if QT_CONFIG(animation)
78class QScrollTimer;
79#endif
80class QScrollerPrivate : public QObject
81{
82 Q_OBJECT
83 Q_DECLARE_PUBLIC(QScroller)
84
85public:
86 QScrollerPrivate(QScroller *q, QObject *target);
87 void init();
88
89 void sendEvent(QObject *o, QEvent *e);
90
91 void setState(QScroller::State s);
92
93 enum ScrollType {
94 ScrollTypeFlick = 0,
95 ScrollTypeScrollTo,
96 ScrollTypeOvershoot
97 };
98
99 struct ScrollSegment {
100 qint64 startTime;
101 qint64 deltaTime;
102 qreal startPos;
103 qreal deltaPos;
104 QEasingCurve curve;
105 qreal stopProgress; // whatever is..
106 qreal stopPos; // ..reached first
107 ScrollType type;
108 };
109
110 bool pressWhileInactive(const QPointF &position, qint64 timestamp);
111 bool moveWhilePressed(const QPointF &position, qint64 timestamp);
112 bool releaseWhilePressed(const QPointF &position, qint64 timestamp);
113 bool moveWhileDragging(const QPointF &position, qint64 timestamp);
114 bool releaseWhileDragging(const QPointF &position, qint64 timestamp);
115 bool pressWhileScrolling(const QPointF &position, qint64 timestamp);
116
117 void timerTick();
118 void timerEventWhileDragging();
119 void timerEventWhileScrolling();
120
121 bool prepareScrolling(const QPointF &position);
122 void handleDrag(const QPointF &position, qint64 timestamp);
123
124 QPointF dpi() const;
125 void setDpi(const QPointF &dpi);
126 void setDpiFromWidget(QWidget *widget);
127
128 void updateVelocity(const QPointF &deltaPixelRaw, qint64 deltaTime);
129 void pushSegment(ScrollType type, qreal deltaTime, qreal stopProgress, qreal startPos, qreal deltaPos, qreal stopPos, QEasingCurve::Type curve, Qt::Orientation orientation);
130 void recalcScrollingSegments(bool forceRecalc = false);
131 qreal scrollingSegmentsEndPos(Qt::Orientation orientation) const;
132 bool scrollingSegmentsValid(Qt::Orientation orientation) const;
133 void createScrollToSegments(qreal v, qreal deltaTime, qreal endPos, Qt::Orientation orientation, ScrollType type);
134 void createScrollingSegments(qreal v, qreal startPos,
135 qreal deltaTime, qreal deltaPos,
136 Qt::Orientation orientation);
137 void createScrollingSegments(const QPointF &v, const QPointF &startPos, const QPointF &ppm);
138
139 void setContentPositionHelperDragging(const QPointF &deltaPos);
140 void setContentPositionHelperScrolling();
141
142 qreal nextSnapPos(qreal p, int dir, Qt::Orientation orientation) const;
143 static qreal nextSegmentPosition(QQueue<ScrollSegment> &segments, qint64 now, qreal oldPos);
144
145 inline int frameRateSkip() const { return properties.d.data()->frameRate; }
146
147 static const char *stateName(QScroller::State state);
148 static const char *inputName(QScroller::Input input);
149
150public slots:
151 void targetDestroyed();
152
153public:
154 // non static
155 QObject *target;
156 QScrollerProperties properties;
157#ifndef QT_NO_GESTURES
158 QFlickGestureRecognizer *recognizer;
159 Qt::GestureType recognizerType;
160#endif
161
162 // scroller state:
163
164 // QPointer<QObject> scrollTarget;
165 QSizeF viewportSize;
166 QRectF contentPosRange;
167 QPointF contentPosition;
168 QPointF overshootPosition; // the number of pixels we are overshooting (before overshootDragResistanceFactor)
169
170 // state
171
172 bool enabled;
173 QScroller::State state;
174 bool firstScroll; // true if we haven't already send a scroll event
175
176 QPointF oldVelocity; // the release velocity of the last drag
177
178 QPointF pressPosition;
179 QPointF lastPosition;
180 qint64 pressTimestamp;
181 qint64 lastTimestamp;
182
183 QPointF dragDistance; // the distance we should move during the next drag timer event
184
185 QQueue<ScrollSegment> xSegments;
186 QQueue<ScrollSegment> ySegments;
187
188 // snap positions
189 QList<qreal> snapPositionsX;
190 qreal snapFirstX;
191 qreal snapIntervalX;
192 QList<qreal> snapPositionsY;
193 qreal snapFirstY;
194 qreal snapIntervalY;
195
196 QPointF pixelPerMeter;
197
198 QElapsedTimer monotonicTimer;
199
200 QPointF releaseVelocity; // the starting velocity of the scrolling state
201#if QT_CONFIG(animation)
202 QScrollTimer *scrollTimer;
203#endif
204
205 QScroller *q_ptr;
206};
207template <>
208class QTypeInfo<QScrollerPrivate::ScrollSegment>
209 : public QTypeInfoMerger<QScrollerPrivate::ScrollSegment, QEasingCurve> {};
210
211
212QT_END_NAMESPACE
213
214#endif // QSCROLLER_P_H
215
216

source code of qtbase/src/widgets/util/qscroller_p.h