plasma-framework/extenderitem.cpp

/*
 * Copyright 2008 by Rob Scheepmaker <r.scheepmaker@student.utwente.nl>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor,
 * Boston, MA  02110-1301  USA
 */

#include "extenderitem.h"

#include <QApplication>
#include <QAction>
#include <QBitmap>
#include <QGraphicsSceneResizeEvent>
#include <QGraphicsSceneMouseEvent>
#include <QGraphicsLinearLayout>
#include <QLayout>
#include <QPainter>
#include <QTimer>

#include <kdebug.h>
#include <kicon.h>
#include <kwindowsystem.h>
#include <kglobalsettings.h>

#include "applet.h"
#include "containment.h"
#include "corona.h"
#include "dialog.h"
#include "extender.h"
#include "framesvg.h"
#include "popupapplet.h"
#include "theme.h"
#include "view.h"

#include "private/applet_p.h"
#include "private/extender_p.h"
#include "private/extenderitem_p.h"

#include "widgets/iconwidget.h"

namespace Plasma
{

class ExtenderItemView : public QGraphicsView
{
public:
    ExtenderItemView(QGraphicsScene *scene, QWidget *parent = 0)
        : QGraphicsView(scene, parent)
    {
        //since this view witll have a really short lifespan it can be checked a single time
        composite = KWindowSystem::compositingActive();
    }

    ~ExtenderItemView()
    {}

    void drawBackground(QPainter *painter, const QRectF &rect)
    {
        if (composite) {
            painter->setCompositionMode(QPainter::CompositionMode_Source);
            painter->fillRect(rect.toAlignedRect(), Qt::transparent);
        } else {
            QGraphicsView::drawBackground(painter, rect);
        }
    }

private:
    bool composite;
};

ExtenderItem::ExtenderItem(Extender *hostExtender, uint extenderItemId)
        : QGraphicsWidget(hostExtender),
          d(new ExtenderItemPrivate(this, hostExtender))
{
    Q_ASSERT(hostExtender);

    //set the extenderId
    if (extenderItemId) {
        d->extenderItemId = extenderItemId;
        ExtenderItemPrivate::s_maxExtenderItemId =
            qMax(ExtenderItemPrivate::s_maxExtenderItemId, extenderItemId);
    } else {
        d->extenderItemId = ++ExtenderItemPrivate::s_maxExtenderItemId;
    }

    //create the toolbox.
    d->toolbox = new QGraphicsWidget(this);
    d->toolboxLayout = new QGraphicsLinearLayout(d->toolbox);
    d->toolbox->setLayout(d->toolboxLayout);


    //create items's configgroup
    KConfigGroup cg = hostExtender->d->applet->config("ExtenderItems");
    KConfigGroup dg = KConfigGroup(&cg, QString::number(d->extenderItemId));

    uint sourceAppletId = dg.readEntry("sourceAppletId", 0);

    //check if we're creating a new item or reinstantiating an existing one.
    if (!sourceAppletId) {
        //The item is new
        dg.writeEntry("sourceAppletPluginName", hostExtender->d->applet->pluginName());
        dg.writeEntry("sourceAppletId", hostExtender->d->applet->id());
        dg.writeEntry("extenderIconName", hostExtender->d->applet->icon());
        d->sourceApplet = hostExtender->d->applet;
        d->collapseIcon = new IconWidget(KIcon(hostExtender->d->applet->icon()), "", this);
    } else {
        //The item already exists.
        d->name = dg.readEntry("extenderItemName", "");
        d->title = dg.readEntry("extenderTitle", "");
        setCollapsed(dg.readEntry("isCollapsed", false));

        QString iconName = dg.readEntry("extenderIconName", "utilities-desktop-extra");
        if (iconName.isEmpty()) {
            iconName = "utilities-desktop-extra";
        }
        d->collapseIcon = new IconWidget(KIcon(iconName), "", this);

        //Find the sourceapplet.
        Corona *corona = hostExtender->d->applet->containment()->corona();
        foreach (Containment *containment, corona->containments()) {
            foreach (Applet *applet, containment->applets()) {
                if (applet->id() == sourceAppletId &&
                        applet->pluginName() == dg.readEntry("sourceAppletPluginName", "")) {
                    d->sourceApplet = applet;
                }
            }
        }
    }

    //make sure we keep monitoring if the source applet still exists, so the return to source icon
    //can be hidden if it is removed.
    connect(d->sourceApplet, SIGNAL(destroyed()), this, SLOT(sourceAppletRemoved()));
    connect(d->collapseIcon, SIGNAL(clicked()), this, SLOT(toggleCollapse()));

    //set the extender we want to move to.
    setExtender(hostExtender);

    //show or hide the return to source icon.
    d->updateToolBox();

    //set the image paths, image sizes and collapseIcon position.
    d->themeChanged();

    setAcceptsHoverEvents(true);

    connect(Plasma::Theme::defaultTheme(), SIGNAL(themeChanged()), this, SLOT(themeChanged()));
}

ExtenderItem::~ExtenderItem()
{
    //make sure the original mousepointer always get's restored.
    if (d->mouseOver) {
        QApplication::restoreOverrideCursor();
    }
    delete d;
}

KConfigGroup ExtenderItem::config() const
{
    KConfigGroup cg = d->extender->d->applet->config("ExtenderItems");
    return KConfigGroup(&cg, QString::number(d->extenderItemId));
}

void ExtenderItem::setTitle(const QString &title)
{
    d->title = title;
    config().writeEntry("extenderTitle", title);
    update();
}

QString ExtenderItem::title() const
{
    return d->title;
}

void ExtenderItem::setName(const QString &name)
{
    d->name = name;
    config().writeEntry("extenderItemName", name);
}

QString ExtenderItem::name() const
{
    return d->name;
}

void ExtenderItem::setWidget(QGraphicsItem *widget)
{
    widget->setParentItem(this);

    QSizeF panelSize(QSizeF(size().width() - d->bgLeft - d->bgRight,
                     d->iconSize() + d->dragTop + d->dragBottom));
    widget->setPos(QPointF(d->bgLeft + d->dragLeft, panelSize.height() +
                                                    d->bgTop + d->dragTop));
    d->widget = widget;
    setCollapsed(isCollapsed()); //updates the size hints.
}

QGraphicsItem *ExtenderItem::widget() const
{
    return d->widget;
}

void ExtenderItem::setIcon(const QIcon &icon)
{
    d->iconName.clear();
    d->collapseIcon->setIcon(icon);
}

void ExtenderItem::setIcon(const QString &icon)
{
    if (icon != d->iconName) {
        d->collapseIcon->setIcon(icon);
        d->iconName = icon;
        config().writeEntry("extenderIconName", icon);
    }
}

QIcon ExtenderItem::icon() const
{
    return d->collapseIcon->icon();
}

void ExtenderItem::setExtender(Extender *extender, const QPointF &pos)
{
    Q_ASSERT(extender);

    if (extender == d->extender) {
        //We're not moving between extenders, so just insert this item back into the layout.
        setParentItem(extender);
        extender->d->addExtenderItem(this, pos);
        return;
    }

    //We are switching extender...
    //first remove this item from the old extender.
    d->extender->d->removeExtenderItem(this);
    emit d->extender->itemDetached(this);

    //move the configuration.
    if (d->hostApplet() && (extender != d->extender)) {
        KConfigGroup c = extender->d->applet->config("ExtenderItems");
        config().reparent(&c);
    }

    d->extender = extender;

    //change parent.
    setParentItem(extender);
    extender->d->addExtenderItem(this, pos);

    //cancel the timer.
    if (d->expirationTimer && isDetached()) {
        d->expirationTimer->stop();
        delete d->expirationTimer;
        d->expirationTimer = 0;
    }

    //set the background svg to that of the extender we're moving to.
    d->themeChanged();

    //we might have to enable or disable the returnToSource button.
    d->updateToolBox();
}

Extender *ExtenderItem::extender() const
{
    return d->extender;
}

bool ExtenderItem::isCollapsed() const
{
    return d->collapsed;
}

void ExtenderItem::setAutoExpireDelay(uint time)
{
    if (!time) {
        if (d->expirationTimer) {
            d->expirationTimer->stop();
            delete d->expirationTimer;
            d->expirationTimer = 0;
        }
        return;
    }

    if (!isDetached()) {
        if (!d->expirationTimer) {
            d->expirationTimer = new QTimer(this);
            connect(d->expirationTimer, SIGNAL(timeout()), this, SLOT(destroy()));
        }

        d->expirationTimer->stop();
        d->expirationTimer->setSingleShot(true);
        d->expirationTimer->setInterval(time);
        d->expirationTimer->start();
    }
}

uint ExtenderItem::autoExpireDelay() const
{
    if (d->expirationTimer) {
        return d->expirationTimer->interval();
    } else {
        return 0;
    }
}

bool ExtenderItem::isDetached() const
{
    if (d->hostApplet()) {
        return (d->sourceApplet != d->hostApplet());
    } else {
        return false;
    }
}

void ExtenderItem::addAction(const QString &name, QAction *action)
{
    Q_ASSERT(action);
    if (d->actionsInOrder.contains(action)) {
        return;
    }

    d->actions.insert(name, action);
    d->actionsInOrder.append(action);
    connect(action, SIGNAL(changed()), this, SLOT(updateToolBox()));
    connect(action, SIGNAL(destroyed(QObject*)), this, SLOT(actionDestroyed(QObject*)));
    d->updateToolBox();
}

QAction *ExtenderItem::action(const QString &name) const
{
    return d->actions.value(name, 0);
}

void ExtenderItem::showCloseButton()
{
    if (d->destroyActionVisibility) {
        return;
    }

    d->destroyActionVisibility = true;
    d->updateToolBox();
}

void ExtenderItem::hideCloseButton()
{
    if (!d->destroyActionVisibility) {
        return;
    }

    d->destroyActionVisibility = false;
    d->updateToolBox();
}

void ExtenderItem::destroy()
{
    if (d->mousePressed) {
        //avoid being destroyed while we're being dragged.
        return;
    }

    d->hostApplet()->config("ExtenderItems").deleteGroup(QString::number(d->extenderItemId));
    d->extender->d->removeExtenderItem(this);
    deleteLater();
}

void ExtenderItem::setCollapsed(bool collapsed)
{
    config().writeEntry("isCollapsed", collapsed);
    d->collapsed = collapsed;

    qreal marginWidth = d->bgLeft + d->bgRight + d->dragLeft + d->dragRight;
    qreal marginHeight = d->bgTop + d->bgBottom + 2 * d->dragTop + 2 * d->dragBottom;

    if (!d->widget) {
        setPreferredSize(QSizeF(200, d->dragHandleRect().height()));
        setMinimumSize(QSizeF(0, d->dragHandleRect().height()));
        //FIXME: wasn't there some sort of QWIDGETMAXSIZE thingy?
        setMaximumSize(QSizeF(1000, d->dragHandleRect().height()));
        setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);
        updateGeometry();
        return;
    }

    d->widget->setVisible(!collapsed);

    QSizeF min;
    QSizeF pref;
    QSizeF max;

    if (d->widget->isWidget()) {
        QGraphicsWidget *graphicsWidget = static_cast<QGraphicsWidget*>(d->widget);
        min = graphicsWidget->minimumSize();
        pref = graphicsWidget->preferredSize();
        max = graphicsWidget->maximumSize();
    } else {
        min = d->widget->boundingRect().size();
        pref = d->widget->boundingRect().size();
        max = d->widget->boundingRect().size();
    }

    if (collapsed) {
        setPreferredSize(QSizeF(pref.width() + marginWidth,
                                d->dragHandleRect().height() + marginHeight));
        setMinimumSize(QSizeF(min.width() + marginWidth,
                              d->dragHandleRect().height() + marginHeight));
        setMaximumSize(QSizeF(max.width() + marginWidth,
                              d->dragHandleRect().height() + marginHeight));
        setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);

        if (d->collapseIcon) {
            d->collapseIcon->setToolTip(i18n("Expand this widget"));
        }
    } else {
        setPreferredSize(QSizeF(pref.width() + marginWidth,
                         pref.height() + d->dragHandleRect().height() + marginHeight));
        setMinimumSize(QSizeF(min.width() + marginWidth,
                              min.height() + d->dragHandleRect().height() + marginHeight));
        setMaximumSize(QSizeF(max.width() + marginWidth,
                              max.height() + d->dragHandleRect().height() + marginHeight));

        if (d->widget->isWidget()) {
            setSizePolicy(QSizePolicy::MinimumExpanding, QSizePolicy::Fixed);
        } else {
            setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
        }

        if (d->collapseIcon) {
            d->collapseIcon->setToolTip(i18n("Collapse this widget"));
        }
    }

    updateGeometry();
    d->extender->d->adjustSizeHints();
}

void ExtenderItem::returnToSource()
{
    if (!d->sourceApplet) {
        return;
    }
    setExtender(d->sourceApplet->d->extender);
}

void ExtenderItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
                         QWidget *widget)
{
    Q_UNUSED(option);
    Q_UNUSED(widget);

    painter->setRenderHint(QPainter::TextAntialiasing, true);
    painter->setRenderHint(QPainter::Antialiasing, true);

    if (d->background->enabledBorders() != (FrameSvg::LeftBorder | FrameSvg::RightBorder) &&
        d->background->enabledBorders()) {
        //Don't paint if only the left and right borders are enabled, we only use the left and right
        //border in this situation to set the correct margins on this item.
        d->background->paintFrame(painter, QPointF(0, 0));
    }

    d->dragger->paintFrame(painter, QPointF(d->bgLeft, d->bgTop));

    //We don't need to paint a title if there is no title.
    if (d->title.isEmpty()) {
        return;
    }

    //set the font for the title.
    Plasma::Theme *theme = Plasma::Theme::defaultTheme();
    QFont font = theme->font(Plasma::Theme::DefaultFont);
    font.setWeight(QFont::Bold);

    //create a pixmap with the title that is faded out at the right side of the titleRect.
    QRectF rect = QRectF(d->titleRect().width() - 30, 0, 30, d->titleRect().height());

    QPixmap pixmap(d->titleRect().size().toSize());
    pixmap.fill(Qt::transparent);

    QPainter p(&pixmap);
    p.setPen(theme->color(Plasma::Theme::TextColor));
    p.setFont(font);
    p.drawText(QRectF(QPointF(0, 0), d->titleRect().size()),
               Qt::TextSingleLine | Qt::AlignVCenter | Qt::AlignLeft,
               d->title);

    // Create the alpha gradient for the fade out effect
    QLinearGradient alphaGradient(0, 0, 1, 0);
    alphaGradient.setCoordinateMode(QGradient::ObjectBoundingMode);
    //TODO: correct handling of right to left text.
    alphaGradient.setColorAt(0, QColor(0, 0, 0, 255));
    alphaGradient.setColorAt(1, QColor(0, 0, 0, 0));

    p.setCompositionMode(QPainter::CompositionMode_DestinationIn);
    p.fillRect(rect, alphaGradient);

    p.end();

    painter->drawPixmap(d->titleRect().topLeft(), pixmap);
}

void ExtenderItem::moveEvent(QGraphicsSceneMoveEvent *event)
{
    Q_UNUSED(event);

    if (d->toplevel) {
        d->toplevel->setSceneRect(sceneBoundingRect());
        d->toplevel->setMask(d->background->mask());
    }
}

void ExtenderItem::resizeEvent(QGraphicsSceneResizeEvent *event)
{
    d->resizeContent(event->newSize());

    if (d->toplevel) {
        d->toplevel->setSceneRect(sceneBoundingRect());
        d->toplevel->setMask(d->background->mask());
    }
}

void ExtenderItem::mousePressEvent(QGraphicsSceneMouseEvent *event)
{
    if (!(d->dragHandleRect().contains(event->pos())) ||
        d->extender->d->applet->immutability() != Plasma::Mutable) {
        event->ignore();
        return;
    }

    QApplication::setOverrideCursor(Qt::ClosedHandCursor);

    d->mousePos = event->pos().toPoint();
    d->deltaScene = pos();
    d->mousePressed = true;
}

void ExtenderItem::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
{
    if (d->mousePressed && !d->dragStarted &&
        (d->mousePos - event->pos().toPoint()).manhattanLength() >= QApplication::startDragDistance()) {
        //start the drag:
        d->dragStarted = true;

        //set the zValue to the maximum.
        d->hostApplet()->raise();
        setZValue(d->hostApplet()->zValue());

        QPointF mousePos = d->scenePosFromScreenPos(event->screenPos());
        if (!mousePos.isNull()) {
            d->extender->itemHoverMoveEvent(this, d->extender->mapFromScene(mousePos));
        }
        d->extender->d->removeExtenderItem(this);

        d->themeChanged();
    } else if (!d->dragStarted) {
        return;
    }

    //keep track of the movement in scene coordinates. we use this to set the position of the
    //applet when remaining in the current view.
    d->deltaScene += event->scenePos() - event->lastScenePos();

    //set a rect in screencoordinates so we can check when we need to move to a toplevel
    //view.
    QRect screenRect = QRect();
    screenRect.setTopLeft(event->screenPos() - d->mousePos);
    screenRect.setSize(d->screenRect().size());

    Corona *corona = d->hostApplet()->containment()->corona();

    if (d->leaveCurrentView(screenRect)) {
        //we're moving the applet to a toplevel view, so place it somewhere out of sight
        //first: in the topleft quadrant.

        if (!d->toplevel) {
            //FIXME: duplication from applethandle
            //create a toplevel view and aim it at the applet.
            corona->addOffscreenWidget(this);

            d->toplevel = new ExtenderItemView(scene(), 0);

            d->toplevel->setWindowFlags(
                Qt::ToolTip | Qt::FramelessWindowHint | Qt::WindowStaysOnTopHint);
            d->toplevel->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
            d->toplevel->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
            d->toplevel->setFrameShape(QFrame::NoFrame);

            d->toplevel->setSceneRect(sceneBoundingRect());
            d->toplevel->setGeometry(screenRect);
            d->toplevel->setMask(d->background->mask());

            d->toplevel->show();
        }

        d->toplevel->setSceneRect(sceneBoundingRect());
        d->toplevel->setGeometry(screenRect);
        d->toplevel->setMask(d->background->mask());
    } else {
        corona->removeOffscreenWidget(this);
        setParentItem(d->hostApplet());
        setPos(d->deltaScene);

       //remove the toplevel view.
        delete d->toplevel;
        d->toplevel = 0;
    }

    //let's insert spacers in applets we're hovering over for some useful visual feedback.
    //check which view we're hovering over and use that information to get the mouse
    //position in scene coordinates (event->scenePos won't work, since it doesn't take in
    //consideration that you're leaving the current view).
    QPointF mousePos = d->scenePosFromScreenPos(event->screenPos());

    //find the extender we're hovering over.
    Extender *targetExtender = 0;

    if (!mousePos.isNull()) {
        foreach (Containment *containment, corona->containments()) {
            foreach (Applet *applet, containment->applets()) {
                if (applet->d->extender &&
                        (applet->sceneBoundingRect().contains(mousePos) ||
                         applet->d->extender->sceneBoundingRect().contains(mousePos))) {
                    targetExtender = applet->d->extender;

                    //check if we're hovering over an popupapplet, and open it up in case it does.
                    PopupApplet *popupApplet = qobject_cast<PopupApplet*>(applet);
                    if (popupApplet && (applet->formFactor() == Plasma::Horizontal ||
                                applet->formFactor() == Plasma::Vertical)) {
                        popupApplet->showPopup();
                    }
                }
            }

            if (containment->sceneBoundingRect().contains(mousePos) && !targetExtender) {
                containment->showDropZone(containment->mapFromScene(mousePos).toPoint());
            } else {
                containment->showDropZone(QPoint());
            }
        }
    }

    //remove any previous spacers.
    if (targetExtender != d->previousTargetExtender) {
        if (d->previousTargetExtender) {
            d->previousTargetExtender->itemHoverLeaveEvent(this);
            d->previousTargetExtender->disconnect(this, SIGNAL(destroyed(QObject*)));
        }

        d->previousTargetExtender = targetExtender;

        //monitor the current previousTargetExtender, so we don't accidently try to remove it's
        //spacer after the extender has been destoryed.
        if (targetExtender) {
            connect(targetExtender, SIGNAL(destroyed(QObject*)),
                    this, SLOT(previousTargetExtenderDestroyed(QObject*)));
        }

        if (targetExtender) {
            targetExtender->itemHoverEnterEvent(this);
        }
    }

    //insert a spacer if the applet accepts detachables.
    if (targetExtender) {
        if (targetExtender->sceneBoundingRect().contains(mousePos)) {
            targetExtender->itemHoverMoveEvent(this, targetExtender->mapFromScene(mousePos));
        }
    }
}

void ExtenderItem::mouseDoubleClickEvent(QGraphicsSceneMouseEvent *event)
{
    if (d->titleRect().contains(event->pos())) {
        d->toggleCollapse();
    }
}

void ExtenderItem::hoverMoveEvent(QGraphicsSceneHoverEvent *event)
{
    if (d->titleRect().contains(event->pos()) &&
        d->extender->d->applet->immutability() == Plasma::Mutable) {
        if (!d->mouseOver) {
            QApplication::setOverrideCursor(Qt::OpenHandCursor);
            d->mouseOver = true;
        }
    } else {
        if (d->mouseOver) {
            QApplication::restoreOverrideCursor();
            d->mouseOver = false;
        }
    }
}

void ExtenderItem::hoverLeaveEvent(QGraphicsSceneHoverEvent *event)
{
    Q_UNUSED(event);

    if (d->mouseOver) {
        QApplication::restoreOverrideCursor();
        d->mouseOver = false;
    }
}

void ExtenderItem::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
{
    if (d->mousePressed) {
        QApplication::restoreOverrideCursor();
    }

    d->mousePressed = false;

    if (d->dragStarted) {
        d->dragStarted = false;
        d->previousTargetExtender = 0;

        //remove the toplevel view
        if (d->toplevel) {
            delete d->toplevel;
            d->toplevel = 0;
        }

        //let's insert spacers in applets we're hovering over for some useful visual feedback.
        //check which view we're hovering over and use that information to get the mouse
        //position in scene coordinates (event->scenePos won't work, since it doesn't take in
        //consideration that you're leaving the current view).
        QPointF mousePos = d->scenePosFromScreenPos(event->screenPos());

        //find the extender we're hovering over.
        Extender *targetExtender = 0;
        Corona *corona = qobject_cast<Corona*>(d->extender->d->applet->scene());

        corona->removeOffscreenWidget(this);

        if (!mousePos.isNull()) {
            foreach (Containment *containment, corona->containments()) {
                containment->showDropZone(QPoint());
                foreach (Applet *applet, containment->applets()) {
                    if (applet->d->extender &&
                        (applet->sceneBoundingRect().contains(mousePos) ||
                         applet->d->extender->sceneBoundingRect().contains(mousePos))) {
                        targetExtender = applet->d->extender;
                    }
                }
            }
        }

        //are we hovering over an applet that accepts extender items?
        if (targetExtender) {
            if (targetExtender->sceneBoundingRect().contains(mousePos)) {
                setExtender(targetExtender, targetExtender->mapFromScene(mousePos));
            } else {
                setExtender(targetExtender);
            }
        } else {
            //apparently, it is not, so instantiate a new ExtenderApplet.
            bool extenderCreated = false;
            mousePos = d->scenePosFromScreenPos(event->screenPos());
            if (!mousePos.isNull()) {
                foreach (Containment *containment, corona->containments()) {
                    if (containment->sceneBoundingRect().contains(mousePos)) {
                        kDebug() << "Instantiate a new ExtenderApplet";

                        //when on a desktopcontainment, we use the widgets topleft corner to
                        //position the applet in the containment, on other containments, we use the
                        //actual mouse position.
                        QPointF position;
                        if (containment->type() == Plasma::Containment::DesktopContainment) {
                            position = containment->mapFromScene(
                                       d->scenePosFromScreenPos(event->screenPos() - d->mousePos));
                        } else {
                            position = containment->mapFromScene(mousePos);
                        }

                        Applet *applet = containment->addApplet("internal:extender",
                                QVariantList(),
                                QRectF(containment->mapFromScene(mousePos), size()));

                        if (applet) {
                            setExtender(applet->d->extender);
                            QSizeF margin = applet->size() - applet->contentsRect().size();
                            applet->setMinimumSize(minimumSize() + margin);
                            applet->setPreferredSize(preferredSize() + margin);
                            applet->resize(preferredSize());

                            extenderCreated = true;
                        } else {
                            kDebug() << "Creating internal:extender applet failed, probably "
                                     << "because widgets are locked.";
                        }
                    }
                }
            }

            //if no containment is at the position where the item is dropped, just move the item
            //back to where it came from.
            if (!extenderCreated) {
                setExtender(extender());
                kDebug() << "Move the item back to where it came from.";
            }
        }
    }
}

ExtenderItemPrivate::ExtenderItemPrivate(ExtenderItem *extenderItem, Extender *hostExtender)
    : q(extenderItem),
      widget(0),
      toolbox(0),
      toplevel(0),
      previousTargetExtender(0),
      extender(hostExtender),
      sourceApplet(0),
      dragger(new FrameSvg(extenderItem)),
      background(new FrameSvg(extenderItem)),
      collapseIcon(0),
      title(QString()),
      mousePressed(false),
      mouseOver(false),
      dragStarted(false),
      destroyActionVisibility(false),
      collapsed(false),
      expirationTimer(0)
{
    dragLeft = dragTop = dragRight = dragBottom = 0;
    bgLeft = bgTop = bgRight = bgBottom = 0;
}

ExtenderItemPrivate::~ExtenderItemPrivate()
{
    delete widget;
    widget = 0;
    delete toplevel;
}

//returns a Rect containing the area of the detachable where the draghandle will be drawn.
QRectF ExtenderItemPrivate::dragHandleRect()
{
    QSizeF panelSize(QSizeF(q->size().width() - bgLeft - bgRight,
                     iconSize() + dragTop + dragBottom));
    return QRectF(QPointF(bgLeft, bgTop), panelSize);
}

QRectF ExtenderItemPrivate::titleRect()
{
    return dragHandleRect().adjusted(dragLeft + collapseIcon->size().width() + 1, dragTop,
                                     -toolbox->size().width() - dragRight, -dragBottom);
}

bool ExtenderItemPrivate::leaveCurrentView(const QRect &rect)
{
    if ((q->sceneBoundingRect().left() < 0)) {
        //always leaveCurrentView when the item is in a Plasma::Dialog which can easy be
        //seen by checking if it is in topleft quadrant and it's not just there because it's
        //being viewed by the toplevel view.
        return true;
    }

    foreach (QWidget *widget, QApplication::topLevelWidgets()) {
        if (widget->geometry().intersects(rect) && widget->isVisible() && widget != toplevel) {
            //is this widget a plasma view, a different view then our current one,
            //AND not a dashboardview?
            QGraphicsView *v = qobject_cast<QGraphicsView*>(widget);
            QGraphicsView *currentV = 0;

            if (hostApplet()) {
                currentV = qobject_cast<QGraphicsView*>(hostApplet()->containment()->view());
            }

            if (v && v != currentV) {
                return true;
            }
        }
    }

    return false;
}

QRect ExtenderItemPrivate::screenRect()
{
    return hostApplet()->containment()->view()
                       ->mapFromScene(q->sceneBoundingRect()).boundingRect();
}

void ExtenderItemPrivate::toggleCollapse()
{
    q->setCollapsed(!q->isCollapsed());
}

void ExtenderItemPrivate::updateToolBox()
{
    Q_ASSERT(toolbox);
    Q_ASSERT(dragger);
    Q_ASSERT(toolboxLayout);

    uint iconHeight = iconSize();

    //TODO: only delete items that actually have to be deleted, current performance is horrible.
    while (toolboxLayout->count()) {
        QGraphicsLayoutItem *icon = toolboxLayout->itemAt(0);
        QGraphicsWidget *widget = dynamic_cast<QGraphicsWidget*>(icon);
        widget->deleteLater();
        toolboxLayout->removeAt(0);
    }

    //add the actions that are actually set to visible.
    foreach (QAction *action, actionsInOrder) {
        if (action->isVisible()) {
            IconWidget *icon = new IconWidget(q);
            icon->setAction(action);
            QSizeF iconSize = icon->sizeFromIconSize(iconHeight);
            icon->setMinimumSize(iconSize);
            icon->setMaximumSize(iconSize);
            toolboxLayout->addItem(icon);
        }
    }

    //add the returntosource icon if we are detached, and have a source applet.
    if (q->isDetached() && sourceApplet) {
        IconWidget *returnToSource = new IconWidget(q);
        returnToSource->setSvg("widgets/configuration-icons", "return-to-source");
        QSizeF iconSize = returnToSource->sizeFromIconSize(iconHeight);
        returnToSource->setMinimumSize(iconSize);
        returnToSource->setMaximumSize(iconSize);

        toolboxLayout->addItem(returnToSource);
        QObject::connect(returnToSource, SIGNAL(clicked()), q, SLOT(returnToSource()));
    }

    //add the close icon if desired.
    if (destroyActionVisibility) {
        IconWidget *destroyAction = new IconWidget(q);
        destroyAction->setSvg("widgets/configuration-icons", "close");
        QSizeF iconSize = destroyAction->sizeFromIconSize(iconHeight);
        destroyAction->setMinimumSize(iconSize);
        destroyAction->setMaximumSize(iconSize);

        toolboxLayout->addItem(destroyAction);
        QObject::connect(destroyAction, SIGNAL(clicked()), q, SLOT(destroy()));
    }

    toolboxLayout->updateGeometry();

    //position the toolbox correctly.
    QSizeF minimum = toolboxLayout->minimumSize();
    toolbox->resize(minimum);
    repositionToolbox();
}

void ExtenderItemPrivate::repositionToolbox()
{
    QSizeF minimum = toolboxLayout->minimumSize();
    toolbox->setPos(q->size().width() - minimum.width() - bgRight,
                    (dragHandleRect().height()/2) -
                    (minimum.height()/2) + bgTop);
}

//TODO: something like this as static function in corona might be a good idea.
QPointF ExtenderItemPrivate::scenePosFromScreenPos(const QPoint &pos) const
{
    //get the stacking order of the toplevel windows and remove the toplevel view that's
    //only here while dragging, since we're not interested in finding that.
    QList<WId> order = KWindowSystem::stackingOrder();
    if (toplevel) {
        order.removeOne(toplevel->winId());
    }

    QGraphicsView *found = 0;
    foreach (QWidget *w, QApplication::topLevelWidgets()) {
        QGraphicsView *v = 0;

        //first check if we're over a Dialog.
        Dialog *dialog = qobject_cast<Dialog*>(w);
        if (dialog) {
            if (dialog->isVisible() && dialog->geometry().contains(pos)) {
                v = qobject_cast<QGraphicsView*>(dialog->layout()->itemAt(0)->widget());
                if (v) {
                    return v->mapToScene(v->mapFromGlobal(pos));
                }
            }
        } else {
            v = qobject_cast<QGraphicsView *>(w);
        }

        //else check if it is a QGV:
        if (v && w->isVisible() && w->geometry().contains(pos)) {
            if (found && order.contains(found->winId())) {
                if (order.indexOf(found->winId()) < order.indexOf(v->winId())) {
                    found = v;
                }
            } else {
                found = v;
            }
        }
    }

    if (!found) {
        return QPointF();
    }

    return found->mapToScene(found->mapFromGlobal(pos));
}

Applet *ExtenderItemPrivate::hostApplet() const
{
    if (extender) {
        return extender->d->applet;
    } else {
        return 0;
    }
}

void ExtenderItemPrivate::themeChanged()
{
    background->setImagePath("widgets/extender-background");
    if (mousePressed) {
        background->setEnabledBorders(FrameSvg::AllBorders);
    } else {
        background->setEnabledBorders(extender->enabledBordersForItem(q));
    }
    background->getMargins(bgLeft, bgTop, bgRight, bgBottom);

    dragger->setImagePath("widgets/extender-dragger");
    dragger->getMargins(dragLeft, dragTop, dragRight, dragBottom);

    QSizeF panelSize(QSizeF(q->size().width() - bgLeft - bgRight,
                     iconSize() + dragTop + dragBottom));

    //resize the collapse icon.
    collapseIcon->resize(collapseIcon->sizeFromIconSize(iconSize()));

    //reposition the collapse icon based on the new margins and size.
    collapseIcon->setPos(bgLeft + dragLeft,
                         panelSize.height()/2 -
                         collapseIcon->size().height()/2 + bgTop);

    //reposition the widget based on the new margins.
    if (widget) {
        widget->setPos(QPointF(bgLeft + dragLeft, panelSize.height() +
                                                  bgTop + dragTop));
    }

    //reposition the toolbox.
    repositionToolbox();

    //setCollapsed recalculates size hints.
    q->setCollapsed(q->isCollapsed());

    if (!q->size().isEmpty())
        resizeContent(q->size());
}

void ExtenderItemPrivate::sourceAppletRemoved()
{
    //the original source applet is removed, set the pointer to 0 and no longer show the return to
    //source icon.
    sourceApplet = 0;
    updateToolBox();
}

qreal ExtenderItemPrivate::iconSize()
{
    //read the icon size hint, and enforce a minimum size of 16x16
    QSizeF size = dragger->elementSize("hint-preferred-icon-size");
    size = size.expandedTo(QSizeF(16,16));

    //return the size of the text, if that is larger then the recommended icon size
    Plasma::Theme *theme = Plasma::Theme::defaultTheme();
    QFont font = theme->font(Plasma::Theme::DefaultFont);
    QFontMetrics fm(font);

    return qMax(size.height(), (qreal) fm.height());
}

void ExtenderItemPrivate::resizeContent(const QSizeF &newSize)
{
    qreal width = newSize.width();
    qreal height = newSize.height();

    //resize the dragger
    dragger->resizeFrame(QSizeF(width - bgLeft - bgRight,
                         iconSize() + dragTop + dragBottom));

    //resize the applet background
    background->resizeFrame(newSize);

    //resize the widget
    if (widget && widget->isWidget()) {
        QSizeF newWidgetSize(width - bgLeft - bgRight - dragLeft - dragRight,
                             height - dragHandleRect().height() - bgTop - bgBottom -
                             2 * dragTop - 2 * dragBottom);

        QGraphicsWidget *graphicsWidget = static_cast<QGraphicsWidget*>(widget);
        graphicsWidget->resize(newWidgetSize);
    }

    //reposition the toolbox.
    repositionToolbox();

    q->update();
}

void ExtenderItemPrivate::previousTargetExtenderDestroyed(QObject *o)
{
    Q_UNUSED(o)
    previousTargetExtender = 0;
}

void ExtenderItemPrivate::actionDestroyed(QObject *o)
{
    QAction *action = static_cast<QAction *>(o);
    QMutableHashIterator<QString, QAction *> hit(actions);
    while (hit.hasNext()) {
        if (hit.next().value() == action) {
            hit.remove();
            break;
        }
    }

    QMutableListIterator<QAction *> lit(actionsInOrder);
    while (lit.hasNext()) {
        if (lit.next() == action) {
            lit.remove();
            break;
        }
    }
}

uint ExtenderItemPrivate::s_maxExtenderItemId = 0;

} // namespace Plasma

#include "extenderitem.moc"