1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
| // http://www.egeek.me
#include "scroller.h"
#include <QtDebug>
#include <QAbstractItemView>
#include <QAbstractScrollArea>
#include <QWebFrame>
#include <QWebView>
#include <QMouseEvent>
#include <QApplication>
#include <QHash>
#include <QSet>
// Undefine to use QtScroller
//#define USE_FLICKCHARM
#ifdef USE_FLICKCHARM
#include "flickcharm.h"
#else
#include "qtscroller.h"
/* Max number of pixels between mouse press and release
events that triggers sending fake mouse events */
#define SINGLE_CLICK_MAX_DIST 15
#endif
class ScrollerPrivate
{
public:
static Scroller *instance();
/* Adjusts (decreases) deceleration factor of scroller to be
able to scroll more. */
static void adjustDecelerationFactor(QtScroller* scroller);
/* Reduces the mouse press delay in case when not only
mouse click events are passed. */
static void reduceMousePressDelay(QtScroller *scroller);
QHash<QWidget *, QPoint> startPoints;
QSet<QEvent *> ignoredEvents;
};
Scroller *ScrollerPrivate::instance()
{
static Scroller scroller;
return &scroller;
}
void ScrollerPrivate::adjustDecelerationFactor(QtScroller *scroller)
{
if (!scroller)
return;
QtScrollerProperties props = scroller->scrollerProperties();
float df = props.scrollMetric(QtScrollerProperties::DecelerationFactor).toFloat();
df /= 2;
props.setScrollMetric(QtScrollerProperties::DecelerationFactor, QVariant(df));
scroller->setScrollerProperties(props);
}
void ScrollerPrivate::reduceMousePressDelay(QtScroller *scroller)
{
if (!scroller)
return;
QtScrollerProperties props = scroller->scrollerProperties();
props.setScrollMetric(QtScrollerProperties::MousePressEventDelay, .1f);
scroller->setScrollerProperties(props);
}
Scroller::Scroller() :
d_ptr(new ScrollerPrivate())
{
}
Scroller::~Scroller()
{
delete d_ptr;
}
void Scroller::activateOn(QWidget *widget, bool withVScrollBar, bool passClickEventsOnly)
{
#ifdef USE_FLICKCHARM
FlickCharm::instance()->activateOn(widget);
#else
QtScroller::ScrollerGestureType type = QtScroller::LeftMouseButtonGesture;
QAbstractScrollArea *scrollArea = qobject_cast<QAbstractScrollArea*>(widget);
if (scrollArea) {
if (!withVScrollBar) {
scrollArea->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
}
scrollArea->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
QAbstractItemView *itemView = qobject_cast<QAbstractItemView*>(scrollArea);
if (itemView) {
// fix scrolling of lists
itemView->setHorizontalScrollMode(QAbstractItemView::ScrollPerPixel);
itemView->setVerticalScrollMode(QAbstractItemView::ScrollPerPixel);
}
if (passClickEventsOnly) {
scrollArea->viewport()->installEventFilter(ScrollerPrivate::instance());
scrollArea->installEventFilter(ScrollerPrivate::instance());
}
QtScroller::grabGesture(scrollArea->viewport(), type);
QtScroller::grabGesture(scrollArea, type);
QtScroller *scroller = QtScroller::scroller(scrollArea->viewport());
ScrollerPrivate::adjustDecelerationFactor(scroller);
if (!passClickEventsOnly) {
ScrollerPrivate::reduceMousePressDelay(scroller);
}
scroller = QtScroller::scroller(scrollArea);
ScrollerPrivate::adjustDecelerationFactor(scroller);
if (!passClickEventsOnly) {
ScrollerPrivate::reduceMousePressDelay(scroller);
}
return;
}
QWebView *webView = qobject_cast<QWebView*>(widget);
if (webView) {
QWebFrame *frame = webView->page()->mainFrame();
if (!withVScrollBar) {
frame->setScrollBarPolicy(Qt::Vertical, Qt::ScrollBarAlwaysOff);
}
frame->setScrollBarPolicy(Qt::Horizontal, Qt::ScrollBarAlwaysOff);
if (passClickEventsOnly) {
webView->installEventFilter(ScrollerPrivate::instance());
}
QtScroller::grabGesture(webView, type);
if (!passClickEventsOnly) {
ScrollerPrivate::reduceMousePressDelay(QtScroller::scroller(webView));
}
return;
}
qWarning() << "Scroller only works on QAbstractScrollArea (and derived classes)";
qWarning() << "or QWebView (and derived classes)";
#endif
}
bool Scroller::eventFilter(QObject *obj, QEvent *evt)
{
#ifndef USE_FLICKCHARM
Q_D(Scroller);
/* to avoid selection in webviews and lists before
scrolling has started, we need to consume all mouse
events, except for single clicks */
QWidget *widget = qobject_cast<QWidget *>(obj);
Q_ASSERT(widget);
switch (evt->type())
{
case QMouseEvent::MouseMove:
/* don't propagate mouse move events */
return true;
case QMouseEvent::MouseButtonPress:
/* on mouse press save the pos to the hash
in order to check if it makes up a single click */
if (d->ignoredEvents.contains(evt))
{
d->ignoredEvents.remove(evt);
return false;
}
else
d->startPoints[widget] = static_cast<QMouseEvent *>(evt)->pos();
return true;
case QMouseEvent::MouseButtonRelease:
if (d->ignoredEvents.contains(evt))
{
d->ignoredEvents.remove(evt);
return false;
}
else if (d->startPoints.contains(widget))
{
QPoint startPos = d->startPoints[widget];
d->startPoints.remove(widget);
/* if the distance is less than a limit,
we consider it a single click */
QPoint pos = static_cast<QMouseEvent *>(evt)->pos();
if ((pos - startPos).manhattanLength() < SINGLE_CLICK_MAX_DIST)
{
QMouseEvent *event1 = new QMouseEvent(QEvent::MouseButtonPress,
pos, Qt::LeftButton,
Qt::LeftButton, Qt::NoModifier);
QMouseEvent *event2 = new QMouseEvent(QEvent::MouseButtonRelease,
pos, Qt::LeftButton,
Qt::LeftButton, Qt::NoModifier);
/* put the artifical events in the ignoredEvents set
to let them pass this method */
d->ignoredEvents << event1 << event2;
/* for some reason, postEvent caused a lot of events,
almost recursively, here */
QApplication::sendEvent(obj, event1);
QApplication::sendEvent(obj, event2);
delete event2;
delete event1;
}
}
return true;
default:
break;
}
#endif
return QObject::eventFilter(obj, evt);
}
|