/*
* Copyright (c) 2008 Nokia Corporation and/or its subsidiary(-ies).
* All rights reserved.
* This component and the accompanying materials are made available
* under the terms of "Eclipse Public License v1.0"
* which accompanies this distribution, and is available
* at the URL "http://www.eclipse.org/legal/epl-v10.html".
*
* Initial Contributors:
* Nokia Corporation - initial contribution.
*
* Contributors:
*
* Description:
*
*/
#include "flickcharm.h"
#include <QAbstractScrollArea>
#include <QApplication>
#include <QBasicTimer>
#include <QEvent>
#include <QHash>
#include <QList>
#include <QMouseEvent>
#include <QScrollBar>
#include "qwebframe.h"
#include "qwebview.h"
#include <QDebug>
struct FlickData {
typedef enum { Steady, Pressed, ManualScroll, AutoScroll, Stop } State;
State state;
QWidget *widget;
QPoint pressPos;
QPoint offset;
QPoint dragPos;
QPoint speed;
QList<QEvent*> ignored;
};
class FlickCharmPrivate
{
public:
QHash<QWidget*, FlickData*> flickData;
QBasicTimer ticker;
};
FlickCharm::FlickCharm(QObject *parent): QObject(parent)
{
d = new FlickCharmPrivate;
}
FlickCharm::~FlickCharm()
{
delete d;
}
void FlickCharm::activateOn(QWidget *widget)
{
QAbstractScrollArea *scrollArea = dynamic_cast<QAbstractScrollArea*>(widget);
if (scrollArea) {
scrollArea->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
scrollArea->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
QWidget *viewport = scrollArea->viewport();
viewport->installEventFilter(this);
scrollArea->installEventFilter(this);
d->flickData.remove(viewport);
d->flickData[viewport] = new FlickData;
d->flickData[viewport]->widget = widget;
d->flickData[viewport]->state = FlickData::Steady;
return;
}
QWebView *webView = dynamic_cast<QWebView*>(widget);
if (webView) {
QWebFrame *frame = webView->page()->mainFrame();
frame->setScrollBarPolicy(Qt::Vertical, Qt::ScrollBarAlwaysOff);
frame->setScrollBarPolicy(Qt::Horizontal, Qt::ScrollBarAlwaysOff);
webView->installEventFilter(this);
d->flickData.remove(webView);
d->flickData[webView] = new FlickData;
d->flickData[webView]->widget = webView;
d->flickData[webView]->state = FlickData::Steady;
return;
}
qWarning() << "FlickCharm only works on QAbstractScrollArea (and derived classes)";
qWarning() << "or QWebView (and derived classes)";
}
void FlickCharm::deactivateFrom(QWidget *widget)
{
QAbstractScrollArea *scrollArea = dynamic_cast<QAbstractScrollArea*>(widget);
if (scrollArea) {
QWidget *viewport = scrollArea->viewport();
viewport->removeEventFilter(this);
scrollArea->removeEventFilter(this);
delete d->flickData[viewport];
d->flickData.remove(viewport);
return;
}
QWebView *webView = dynamic_cast<QWebView*>(widget);
if (webView) {
webView->removeEventFilter(this);
delete d->flickData[webView];
d->flickData.remove(webView);
return;
}
}
static QPoint scrollOffset(QWidget *widget)
{
int x = 0, y = 0;
QAbstractScrollArea *scrollArea = dynamic_cast<QAbstractScrollArea*>(widget);
if (scrollArea) {
x = scrollArea->horizontalScrollBar()->value();
y = scrollArea->verticalScrollBar()->value();
}
QWebView *webView = dynamic_cast<QWebView*>(widget);
if (webView) {
QWebFrame *frame = webView->page()->mainFrame();
x = frame->evaluateJavaScript("window.scrollX").toInt();
y = frame->evaluateJavaScript("window.scrollY").toInt();
}
return QPoint(x, y);
}
static void setScrollOffset(QWidget *widget, const QPoint &p)
{
QAbstractScrollArea *scrollArea = dynamic_cast<QAbstractScrollArea*>(widget);
if (scrollArea) {
scrollArea->horizontalScrollBar()->setValue(p.x());
scrollArea->verticalScrollBar()->setValue(p.y());
}
widget->update(); // hab - added to force repainting of overlapping widgets.
QWebView *webView = dynamic_cast<QWebView*>(widget);
QWebFrame *frame = webView ? webView->page()->mainFrame() : 0;
if (frame)
frame->evaluateJavaScript(QString("window.scrollTo(%1,%2);").arg(p.x()).arg(p.y()));
}
static QPoint deaccelerate(const QPoint &speed, int a = 1, int max = 64)
{
int x = qBound(-max, speed.x(), max);
int y = qBound(-max, speed.y(), max);
x = (x == 0) ? x : (x > 0) ? qMax(0, x - a) : qMin(0, x + a);
y = (y == 0) ? y : (y > 0) ? qMax(0, y - a) : qMin(0, y + a);
return QPoint(x, y);
}
bool FlickCharm::eventFilter(QObject *object, QEvent *event)
{
if (!object->isWidgetType())
return false;
QEvent::Type type = event->type();
if (type != QEvent::MouseButtonPress &&
type != QEvent::MouseButtonRelease &&
type != QEvent::MouseMove)
return false;
QMouseEvent *mouseEvent = dynamic_cast<QMouseEvent*>(event);
if (!mouseEvent || mouseEvent->modifiers() != Qt::NoModifier)
return false;
QWidget *viewport = dynamic_cast<QWidget*>(object);
FlickData *data = d->flickData.value(viewport);
if (!viewport || !data || data->ignored.removeAll(event))
return false;
if (type == QEvent::MouseMove){
//Throw away spurious mouse moves on mac
if(data->pressPos == mouseEvent->pos()){
return false;
}
}
bool consumed = false;
switch (data->state) {
case FlickData::Steady:
if (mouseEvent->type() == QEvent::MouseButtonPress)
if (mouseEvent->buttons() == Qt::LeftButton) {
consumed = true;
data->state = FlickData::Pressed;
data->pressPos = mouseEvent->pos();
data->offset = scrollOffset(data->widget);
}
break;
case FlickData::Pressed:
if (mouseEvent->type() == QEvent::MouseButtonRelease) {
consumed = true;
data->state = FlickData::Steady;
QMouseEvent *event1 = new QMouseEvent(QEvent::MouseButtonPress,
data->pressPos, Qt::LeftButton,
Qt::LeftButton, Qt::NoModifier);
QMouseEvent *event2 = new QMouseEvent(*mouseEvent);
data->ignored << event1;
data->ignored << event2;
QApplication::postEvent(object, event1);
QApplication::postEvent(object, event2);
}
if (mouseEvent->type() == QEvent::MouseMove) {
consumed = true;
data->state = FlickData::ManualScroll;
data->dragPos = QCursor::pos();
if (!d->ticker.isActive())
d->ticker.start(20, this);
}
break;
case FlickData::ManualScroll:
if (mouseEvent->type() == QEvent::MouseMove) {
consumed = true;
QPoint delta = mouseEvent->pos() - data->pressPos;
setScrollOffset(data->widget, data->offset - delta);
}
if (mouseEvent->type() == QEvent::MouseButtonRelease) {
consumed = true;
data->state = FlickData::AutoScroll;
}
break;
case FlickData::AutoScroll:
if (mouseEvent->type() == QEvent::MouseButtonPress) {
consumed = true;
data->state = FlickData::Stop;
data->speed = QPoint(0, 0);
}
if (mouseEvent->type() == QEvent::MouseButtonRelease) {
consumed = true;
data->state = FlickData::Steady;
data->speed = QPoint(0, 0);
}
break;
case FlickData::Stop:
if (mouseEvent->type() == QEvent::MouseButtonRelease) {
consumed = true;
data->state = FlickData::Steady;
}
if (mouseEvent->type() == QEvent::MouseMove) {
consumed = true;
data->state = FlickData::ManualScroll;
data->dragPos = QCursor::pos();
if (!d->ticker.isActive())
d->ticker.start(20, this);
}
break;
default:
break;
}
return consumed;
}
void FlickCharm::timerEvent(QTimerEvent *event)
{
int count = 0;
QHashIterator<QWidget*, FlickData*> item(d->flickData);
while (item.hasNext()) {
item.next();
FlickData *data = item.value();
if (data->state == FlickData::ManualScroll) {
count++;
data->speed = QCursor::pos() - data->dragPos;
data->dragPos = QCursor::pos();
}
if (data->state == FlickData::AutoScroll) {
count++;
data->speed = deaccelerate(data->speed);
QPoint p = scrollOffset(data->widget);
setScrollOffset(data->widget, p - data->speed);
if (data->speed == QPoint(0, 0))
data->state = FlickData::Steady;
}
}
if (!count)
d->ticker.stop();
QObject::timerEvent(event);
}