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/***************************************************************************
* Copyright (C) 2008 by Peter Penz <[email protected]> *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program; if not, write to the *
* Free Software Foundation, Inc., *
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA *
***************************************************************************/
#include "dolphinviewautoscroller.h"
#include <QAbstractItemView>
#include <QApplication>
#include <QCursor>
#include <QEvent>
#include <QMouseEvent>
#include <QScrollBar>
#include <QTimer>
#include <math.h>
DolphinViewAutoScroller::DolphinViewAutoScroller(QAbstractItemView* parent) :
QObject(parent),
m_rubberBandSelection(false),
m_keyPressed(false),
m_horizontalScrollInc(0),
m_verticalScrollInc(0),
m_itemView(parent),
m_timer(0)
{
m_itemView->setAutoScroll(false);
m_itemView->viewport()->installEventFilter(this);
m_itemView->installEventFilter(this);
m_timer = new QTimer(this);
m_timer->setSingleShot(false);
m_timer->setInterval(1000 / 25); // 25 frames per second
connect(m_timer, SIGNAL(timeout()), this, SLOT(scrollViewport()));
}
DolphinViewAutoScroller::~DolphinViewAutoScroller()
{
}
bool DolphinViewAutoScroller::isActive() const
{
return m_timer->isActive();
}
void DolphinViewAutoScroller::handleCurrentIndexChange(const QModelIndex& current,
const QModelIndex& previous)
{
// When the autoscroller is inactive and a key has been pressed, it must be
// assured that the current item stays visible. The check whether the previous
// item is valid is important because of #197951. The keypress check is done
// because of #199833.
if (current.isValid() && (previous.isValid() || m_keyPressed) && !isActive()) {
m_itemView->scrollTo(current);
}
}
bool DolphinViewAutoScroller::eventFilter(QObject* watched, QEvent* event)
{
if (watched == m_itemView->viewport()) {
switch (event->type()) {
case QEvent::MouseButtonPress:
if (static_cast<QMouseEvent*>(event)->button() == Qt::LeftButton) {
m_rubberBandSelection = true;
}
break;
case QEvent::MouseMove:
if (m_rubberBandSelection) {
triggerAutoScroll();
}
break;
case QEvent::MouseButtonRelease:
m_rubberBandSelection = false;
stopAutoScroll();
break;
case QEvent::DragEnter:
case QEvent::DragMove:
m_rubberBandSelection = false;
triggerAutoScroll();
break;
case QEvent::Drop:
case QEvent::DragLeave:
m_rubberBandSelection = false;
stopAutoScroll();
break;
default:
break;
}
} else if (watched == m_itemView) {
switch (event->type()) {
case QEvent::KeyPress:
m_keyPressed = true;
break;
case QEvent::KeyRelease:
m_keyPressed = false;
break;
default:
break;
}
}
return QObject::eventFilter(watched, event);
}
void DolphinViewAutoScroller::scrollViewport()
{
QScrollBar* verticalScrollBar = m_itemView->verticalScrollBar();
if (verticalScrollBar != 0) {
const int value = verticalScrollBar->value();
verticalScrollBar->setValue(value + m_verticalScrollInc);
}
QScrollBar* horizontalScrollBar = m_itemView->horizontalScrollBar();
if (horizontalScrollBar != 0) {
const int value = horizontalScrollBar->value();
horizontalScrollBar->setValue(value + m_horizontalScrollInc);
}
if (m_rubberBandSelection) {
// The scrolling does not lead to an update of the rubberband
// selection. Fake a mouse move event to let the QAbstractItemView
// update the rubberband.
QWidget* viewport = m_itemView->viewport();
const QPoint pos = viewport->mapFromGlobal(QCursor::pos());
QMouseEvent event(QEvent::MouseMove, pos, Qt::LeftButton, Qt::LeftButton, QApplication::keyboardModifiers());
QCoreApplication::sendEvent(viewport, &event);
}
}
void DolphinViewAutoScroller::triggerAutoScroll()
{
const bool verticalScrolling = (m_itemView->verticalScrollBar() != 0) &&
m_itemView->verticalScrollBar()->isVisible();
const bool horizontalScrolling = (m_itemView->horizontalScrollBar() != 0) &&
m_itemView->horizontalScrollBar()->isVisible();
if (!verticalScrolling && !horizontalScrolling) {
// no scrollbars are shown at all, so no autoscrolling is necessary
return;
}
QWidget* viewport = m_itemView->viewport();
const QPoint pos = viewport->mapFromGlobal(QCursor::pos());
if (verticalScrolling) {
m_verticalScrollInc = calculateScrollIncrement(pos.y(), viewport->height());
}
if (horizontalScrolling) {
m_horizontalScrollInc = calculateScrollIncrement(pos.x(), viewport->width());
}
if (m_timer->isActive()) {
if ((m_horizontalScrollInc == 0) && (m_verticalScrollInc == 0)) {
m_timer->stop();
}
} else if ((m_horizontalScrollInc != 0) || (m_verticalScrollInc != 0)) {
m_timer->start();
}
}
void DolphinViewAutoScroller::stopAutoScroll()
{
m_timer->stop();
m_horizontalScrollInc = 0;
m_verticalScrollInc = 0;
}
int DolphinViewAutoScroller::calculateScrollIncrement(int cursorPos, int rangeSize) const
{
int inc = 0;
const int minSpeed = 4;
const int maxSpeed = 768;
const int speedLimiter = 48;
const int autoScrollBorder = 64;
if (cursorPos < autoScrollBorder) {
inc = -minSpeed + qAbs(cursorPos - autoScrollBorder) * (cursorPos - autoScrollBorder) / speedLimiter;
if (inc < -maxSpeed) {
inc = -maxSpeed;
}
} else if (cursorPos > rangeSize - autoScrollBorder) {
inc = minSpeed + qAbs(cursorPos - rangeSize + autoScrollBorder) * (cursorPos - rangeSize + autoScrollBorder) / speedLimiter;
if (inc > maxSpeed) {
inc = maxSpeed;
}
}
return inc;
}
#include "dolphinviewautoscroller.moc"
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