Developer Documentation

SpinBoxEventFilter.cc
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40 \*===========================================================================*/
41
42 //#define VERBOSE_DEBUGGING_OUTPUT
43
44 #include "SpinBoxEventFilter.hh"
45
46 #include <QAbstractSpinBox>
47 #include <QEvent>
48 #include <QMetaEnum>
49 #include <stack>
50
51 #ifdef VERBOSE_DEBUGGING_OUTPUT
52 #include <iostream>
53 #endif
54
55 SpinBoxEventFilter::SpinBoxEventFilter(QObject *parent) :
56 QObject(parent), scrolling(false) {
57
58 scrollingTimer.setSingleShot(true);
59 scrollingTimer.setInterval(500);
60
61 connect(&scrollingTimer, SIGNAL( timeout() ), this, SLOT( unsetScrolling() ));
62 }
63
64 SpinBoxEventFilter::~SpinBoxEventFilter() {
65 }
66
67 bool SpinBoxEventFilter::eventFilter(QObject *object, QEvent *event) {
68
69 if (event->type() != QEvent::Wheel) return QObject::eventFilter(object, event);
70
71 QWidget *widget = qobject_cast<QWidget*>(object);
72
73 if (scrollAreas.find(widget) != scrollAreas.end()) {
74 #ifdef VERBOSE_DEBUGGING_OUTPUT
75 std::cout << "Reset isScrolling." << std::endl;
76 #endif
77 setScrolling();
78 return QObject::eventFilter(object, event);
79 }
80
81 if (!isScrolling() && widget->isEnabled()) {
82 #ifdef VERBOSE_DEBUGGING_OUTPUT
83 std::cout << "Not scrolling. Letting wheel event pass." << std::endl;
84 #endif
85 return QObject::eventFilter(object, event);
86 }
87
88 setScrolling();
89 event->ignore();
90 #ifdef VERBOSE_DEBUGGING_OUTPUT
91 std::cout << "Swallowing wheel event." << std::endl;
92 #endif
93 return true;
94
95 //#ifdef VERBOSE_DEBUGGING_OUTPUT
96 // std::cout << "Not a spin box. Letting wheel event pass." << std::endl;
97 //#endif
98 // return QObject::eventFilter(object, event);
99 }
100
101 inline bool SpinBoxEventFilter::isScrolling() {
102 return scrolling;
103 }
104
105 void SpinBoxEventFilter::hookUpToWidgetTree(QWidget *root_widget) {
106 std::stack<QWidget*> dfs;
107 dfs.push(root_widget);
108
109 while (!dfs.empty()) {
110 QWidget *cur = dfs.top(); dfs.pop();
111
112 cur->installEventFilter(this);
113
114 const QObjectList &children = cur->children();
115 for (QObjectList::const_iterator it = children.begin(), it_end = children.end();
116 it != it_end; ++it) {
117
118 QWidget *widget = qobject_cast<QWidget*>(*it);
119 if (widget)
120 dfs.push(widget);
121 }
122 }
123 }
124
125 void SpinBoxEventFilter::registerScrollArea(QWidget *scrollArea) {
126 scrollAreas.insert(scrollArea);
127 scrollArea->installEventFilter(this);
128 }
129
130 void SpinBoxEventFilter::setScrolling() {
131 scrolling = true;
132 scrollingTimer.start();
133 }
134
135 void SpinBoxEventFilter::unsetScrolling() {
136 #ifdef VERBOSE_DEBUGGING_OUTPUT
137 std::cout << "Scrolling timeout." << std::endl;
138 #endif
139 scrolling = false;
140 }