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/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** Contact: Qt Software Information (qt-info@nokia.com)
**
** This file is part of the Graphics Dojo project on Qt Labs.
**
** This file may be used under the terms of the GNU General Public
** License version 2.0 or 3.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of
** this file. Please review the following information to ensure GNU
** General Public Licensing requirements will be met:
** http://www.fsf.org/licensing/licenses/info/GPLv2.html and
** http://www.gnu.org/copyleft/gpl.html.
**
** If you are unsure which license is appropriate for your use, please
** contact the sales department at qt-sales@nokia.com.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
****************************************************************************/
#include <QtCore>
#include <QtGui>
#include <QtWebKit>
#if QT_VERSION < 0x0040500
#error You need Qt 4.5 or newer
#endif
#define SNAP_THRESHOLD 10
class SnapView: public QWebView
{
public:
SnapView(): QWebView(), snapEnabled(true) {
setWindowTitle("Snap-scrolling is ON");
}
private:
bool snapEnabled;
// rects hit by the line, in main frame's view coordinate
QList<QRect> hitBoundingRects(const QLine &line) {
QList<QRect> hitRects;
const int points = 8;
QPoint delta(line.dx() / points, line.dy() / points);
QPoint point = line.p1();
for (int i = 0; i < points - 1; ++i) {
point += delta;
QWebHitTestResult hit = page()->mainFrame()->hitTestContent(point);
if (!hit.boundingRect().isEmpty())
hitRects += hit.boundingRect();
}
return hitRects;
}
void keyPressEvent(QKeyEvent *event) {
// toggle snapping
if (event->key() == Qt::Key_F3) {
snapEnabled = !snapEnabled;
if (snapEnabled)
setWindowTitle("Snap-scrolling is ON");
else
setWindowTitle("Snap-scrolling is OFF");
event->accept();
return;
}
// no snapping? do not bother...
if (!snapEnabled) {
QWebView::keyReleaseEvent(event);
return;
}
QPoint previousOffset = page()->mainFrame()->scrollPosition();
QWebView::keyReleaseEvent(event);
if (!event->isAccepted())
return;
if (event->key() == Qt::Key_Down) {
QPoint ofs = page()->mainFrame()->scrollPosition();
int jump = ofs.y() - previousOffset.y();
if (jump == 0)
return;
jump += SNAP_THRESHOLD;
QList<QRect> rects = hitBoundingRects(QLine(1, 1, width() - 1, 1));
for (int i = 0; i < rects.count(); ++i) {
int j = rects[i].top() - previousOffset.y();
if (j > SNAP_THRESHOLD && j < jump)
jump = j;
}
page()->mainFrame()->setScrollPosition(previousOffset + QPoint(0, jump));
}
}
};
int main(int argc, char **argv)
{
QApplication app(argc, argv);
SnapView view;
view.load(QUrl("http://news.bbc.co.uk/text_only.stm"));
view.resize(320, 500);
view.show();
QMessageBox::information(&view, "Hint", "Use F3 to toggle snapping on and off");
return app.exec();
}
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