kde-extraapps/gwenview/lib/thumbnailview/previewitemdelegate.cpp

// vim: set tabstop=4 shiftwidth=4 expandtab:
/*
Gwenview: an image viewer
Copyright 2008 Aurélien Gâteau <agateau@kde.org>

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, Cambridge, MA 02110-1301, USA.

*/
// Self
#include "moc_previewitemdelegate.cpp"

// Qt
#include <QHash>
#include <QHBoxLayout>
#include <QtGui/qevent.h>
#include <QLabel>
#include <QPainter>
#include <QPainterPath>
#include <QParallelAnimationGroup>
#include <QPointer>
#include <QPropertyAnimation>
#include <QSequentialAnimationGroup>

// KDE
#include <KDebug>
#include <KDirModel>
#include <KGlobalSettings>
#include <KLineEdit>
#include <KLocale>
#include <KUrl>

// Local
#include "contextbarbutton.h"
#include "itemeditor.h"
#include "paintutils.h"
#include "thumbnailview.h"
#include "timeutils.h"

// Define this to be able to fine tune the rendering of the selection
// background through a config file
//#define FINETUNE_SELECTION_BACKGROUND
#ifdef FINETUNE_SELECTION_BACKGROUND
#include <QDir>
#include <QSettings>
#endif

//#define DEBUG_DRAW_BORDER
//#define DEBUG_DRAW_CURRENT

namespace Gwenview
{

/**
 * Space between the item outer rect and the content, and between the
 * thumbnail and the caption
 */
const int ITEM_MARGIN = 5;

/** How darker is the border line around selection */
const int SELECTION_BORDER_DARKNESS = 140;

/** Radius of the selection rounded corners, in pixels */
const int SELECTION_RADIUS = 5;

/** Space between the item outer rect and the context bar */
const int CONTEXTBAR_MARGIN = 1;

/** How dark is the shadow, 0 is invisible, 255 is as dark as possible */
const int SHADOW_STRENGTH = 128;

/** How many pixels around the thumbnail are shadowed */
const int SHADOW_SIZE = 4;

static KFileItem fileItemForIndex(const QModelIndex& index)
{
    Q_ASSERT(index.isValid());
    QVariant data = index.data(KDirModel::FileItemRole);
    return qvariant_cast<KFileItem>(data);
}

static KUrl urlForIndex(const QModelIndex& index)
{
    KFileItem item = fileItemForIndex(index);
    return item.url();
}

struct PreviewItemDelegatePrivate
{
    /**
     * Maps full text to elided text.
     */
    mutable QHash<QString, QString> mElidedTextCache;

    // Key is height * 1000 + width
    typedef QHash<int, QPixmap> ShadowCache;
    mutable ShadowCache mShadowCache;

    PreviewItemDelegate* q;
    ThumbnailView* mView;
    QWidget* mContextBar;
    QToolButton* mSaveButton;
    QPixmap mSaveButtonPixmap;

    QToolButton* mToggleSelectionButton;
    QToolButton* mFullScreenButton;
    QToolButton* mRotateLeftButton;
    QToolButton* mRotateRightButton;

    QPersistentModelIndex mIndexUnderCursor;
    QSize mThumbnailSize;
    PreviewItemDelegate::ThumbnailDetails mDetails;
    PreviewItemDelegate::ContextBarActions mContextBarActions;
    Qt::TextElideMode mTextElideMode;

    void initSaveButtonPixmap()
    {
        if (!mSaveButtonPixmap.isNull()) {
            return;
        }
        // Necessary otherwise we won't see the save button itself
        mSaveButton->adjustSize();

        mSaveButtonPixmap = QPixmap(mSaveButton->sizeHint());
        mSaveButtonPixmap.fill(Qt::transparent);
        mSaveButton->render(&mSaveButtonPixmap, QPoint(), QRegion(), QWidget::DrawChildren);
    }

    void showContextBar(const QRect& rect, const QPixmap& thumbnailPix)
    {
        if (mContextBarActions == PreviewItemDelegate::NoAction) {
            return;
        }
        mContextBar->adjustSize();
        // Center bar, except if only showing SelectionAction.
        const int posX = mContextBarActions == PreviewItemDelegate::SelectionAction
            ? 0
            : (rect.width() - mContextBar->width()) / 2;
        const int posY = qMax(CONTEXTBAR_MARGIN, mThumbnailSize.height() - thumbnailPix.height() - mContextBar->height());
        mContextBar->move(rect.topLeft() + QPoint(posX, posY));
        mContextBar->show();
    }

    bool hoverEventFilter(QHoverEvent* event)
    {
        QModelIndex index = mView->indexAt(event->pos());
        if (index != mIndexUnderCursor) {
            updateHoverUi(index);
        } else {
            // Same index, nothing to do, but repaint anyway in case we are
            // over the rating row
            mView->update(mIndexUnderCursor);
        }
        return false;
    }

    void updateHoverUi(const QModelIndex& index)
    {
        QModelIndex oldIndex = mIndexUnderCursor;
        mIndexUnderCursor = index;
        mView->update(oldIndex);

        if (KGlobalSettings::singleClick() && KGlobalSettings::changeCursorOverIcon()) {
            mView->setCursor(mIndexUnderCursor.isValid() ? Qt::PointingHandCursor : Qt::ArrowCursor);
        }

        if (mIndexUnderCursor.isValid()) {
            updateToggleSelectionButton();
            updateImageButtons();

            const QRect rect = mView->visualRect(mIndexUnderCursor);
            const QPixmap thumbnailPix = mView->thumbnailForIndex(index);
            showContextBar(rect, thumbnailPix);
            if (mView->isModified(mIndexUnderCursor)) {
                showSaveButton(rect);
            } else {
                mSaveButton->hide();
            }

            mView->update(mIndexUnderCursor);

        } else {
            mContextBar->hide();
            mSaveButton->hide();
        }
    }

    bool mouseButtonEventFilter(QEvent::Type type)
    {
        return false;
    }

    QPoint saveButtonPosition(const QRect& itemRect) const
    {
        QSize buttonSize = mSaveButton->sizeHint();
        int posX = itemRect.right() - buttonSize.width();
        int posY = itemRect.top() + mThumbnailSize.height() + 2 * ITEM_MARGIN - buttonSize.height();

        return QPoint(posX, posY);
    }

    void showSaveButton(const QRect& itemRect) const
    {
        mSaveButton->move(saveButtonPosition(itemRect));
        mSaveButton->show();
    }

    void drawBackground(QPainter* painter, const QRect& rect, const QColor& bgColor, const QColor& borderColor) const
    {
        int bgH, bgS, bgV;
        int borderH, borderS, borderV, borderMargin;
#ifdef FINETUNE_SELECTION_BACKGROUND
        QSettings settings(QDir::homePath() + "/colors.ini");
        bgH = settings.integer("bg/h");
        bgS = settings.integer("bg/s");
        bgV = settings.integer("bg/v");
        borderH = settings.integer("border/h");
        borderS = settings.integer("border/s");
        borderV = settings.integer("border/v");
        borderMargin = settings.integer("border/margin");
#else
        bgH = 0;
        bgS = -20;
        bgV = 43;
        borderH = 0;
        borderS = -100;
        borderV = 60;
        borderMargin = 1;
#endif
        painter->setRenderHint(QPainter::Antialiasing);

        QRectF rectF = QRectF(rect).adjusted(0.5, 0.5, -0.5, -0.5);

        QPainterPath path = PaintUtils::roundedRectangle(rectF, SELECTION_RADIUS);

        QLinearGradient gradient(rectF.topLeft(), rectF.bottomLeft());
        gradient.setColorAt(0, PaintUtils::adjustedHsv(bgColor, bgH, bgS, bgV));
        gradient.setColorAt(1, bgColor);
        painter->fillPath(path, gradient);

        painter->setPen(borderColor);
        painter->drawPath(path);

        painter->setPen(PaintUtils::adjustedHsv(borderColor, borderH, borderS, borderV));
        rectF = rectF.adjusted(borderMargin, borderMargin, -borderMargin, -borderMargin);
        path = PaintUtils::roundedRectangle(rectF, SELECTION_RADIUS);
        painter->drawPath(path);
    }

    void drawShadow(QPainter* painter, const QRect& rect) const
    {
        const QPoint shadowOffset(-SHADOW_SIZE, -SHADOW_SIZE + 1);

        int key = rect.height() * 1000 + rect.width();

        ShadowCache::Iterator it = mShadowCache.find(key);
        if (it == mShadowCache.end()) {
            QSize size = QSize(rect.width() + 2 * SHADOW_SIZE, rect.height() + 2 * SHADOW_SIZE);
            QColor color(0, 0, 0, SHADOW_STRENGTH);
            QPixmap shadow = PaintUtils::generateFuzzyRect(size, color, SHADOW_SIZE);
            it = mShadowCache.insert(key, shadow);
        }
        painter->drawPixmap(rect.topLeft() + shadowOffset, it.value());
    }

    void drawText(QPainter* painter, const QRect& rect, const QColor& fgColor, const QString& fullText) const
    {
        QFontMetrics fm = mView->fontMetrics();

        // Elide text
        QString text;
        QHash<QString, QString>::const_iterator it = mElidedTextCache.constFind(fullText);
        if (it == mElidedTextCache.constEnd()) {
            text = fm.elidedText(fullText, mTextElideMode, rect.width());
            mElidedTextCache[fullText] = text;
        } else {
            text = it.value();
        }

        // Compute x pos
        int posX;
        if (text.length() == fullText.length()) {
            // Not elided, center text
            posX = (rect.width() - fm.width(text)) / 2;
        } else {
            // Elided, left align
            posX = 0;
        }

        // Draw text
        painter->setPen(fgColor);
        painter->drawText(rect.left() + posX, rect.top() + fm.ascent(), text);
    }

    int itemWidth() const
    {
        return mThumbnailSize.width() + 2 * ITEM_MARGIN;
    }

    int itemHeight() const
    {
        const int lineHeight = mView->fontMetrics().height();
        int textHeight = 0;
        if (mDetails & PreviewItemDelegate::FileNameDetail) {
            textHeight += lineHeight;
        }
        if (mDetails & PreviewItemDelegate::DateDetail) {
            textHeight += lineHeight;
        }
        if (mDetails & PreviewItemDelegate::ImageSizeDetail) {
            textHeight += lineHeight;
        }
        if (mDetails & PreviewItemDelegate::FileSizeDetail) {
            textHeight += lineHeight;
        }
        if (textHeight == 0) {
            // Keep at least one row of text, so that we can show folder names
            textHeight = lineHeight;
        }
        return mThumbnailSize.height() + textHeight + 3 * ITEM_MARGIN;
    }

    void selectIndexUnderCursorIfNoMultiSelection()
    {
        if (mView->selectionModel()->selectedIndexes().size() <= 1) {
            mView->setCurrentIndex(mIndexUnderCursor);
        }
    }

    void updateToggleSelectionButton()
    {
        mToggleSelectionButton->setIcon(SmallIcon(
                                            mView->selectionModel()->isSelected(mIndexUnderCursor) ? "list-remove" : "list-add"
                                        ));
    }

    void updateImageButtons()
    {
        const KFileItem item = fileItemForIndex(mIndexUnderCursor);
        const bool isImage = !item.isDir();
        mFullScreenButton->setEnabled(isImage);
        mRotateLeftButton->setEnabled(isImage);
        mRotateRightButton->setEnabled(isImage);
    }

    void updateContextBar()
    {
        if (mContextBarActions == PreviewItemDelegate::NoAction) {
            mContextBar->hide();
            return;
        }
        const int width = itemWidth();
        const int buttonWidth = mRotateRightButton->sizeHint().width();
        mFullScreenButton->setVisible(mContextBarActions & PreviewItemDelegate::FullScreenAction);
        bool rotate = mContextBarActions & PreviewItemDelegate::RotateAction;
        mRotateLeftButton->setVisible(rotate && width >= 3 * buttonWidth);
        mRotateRightButton->setVisible(rotate && width >= 4 * buttonWidth);
        mContextBar->adjustSize();
    }

    void updateViewGridSize()
    {
        mView->setGridSize(QSize(itemWidth(), itemHeight()));
    }
};

PreviewItemDelegate::PreviewItemDelegate(ThumbnailView* view)
: QItemDelegate(view)
, d(new PreviewItemDelegatePrivate)
{
    d->q = this;
    d->mView = view;
    view->viewport()->installEventFilter(this);

    // Set this attribute so that the viewport receives QEvent::HoverMove and
    // QEvent::HoverLeave events. We use these events in the event filter
    // installed on the viewport.
    // Some styles set this attribute themselves (Oxygen and Skulpture do) but
    // others do not (Plastique, Cleanlooks...)
    view->viewport()->setAttribute(Qt::WA_Hover);

    d->mThumbnailSize = view->thumbnailSize();
    d->mDetails = FileNameDetail;
    d->mContextBarActions = SelectionAction | FullScreenAction | RotateAction;
    d->mTextElideMode = Qt::ElideRight;

    connect(view, SIGNAL(rowsRemovedSignal(QModelIndex,int,int)),
            SLOT(slotRowsChanged()));
    connect(view, SIGNAL(rowsInsertedSignal(QModelIndex,int,int)),
            SLOT(slotRowsChanged()));


    connect(view, SIGNAL(thumbnailSizeChanged(QSize)),
            SLOT(setThumbnailSize(QSize)));

    // Button frame
    d->mContextBar = new QWidget(d->mView->viewport());
    d->mContextBar->hide();

    d->mToggleSelectionButton = new ContextBarButton("list-add");
    connect(d->mToggleSelectionButton, SIGNAL(clicked()),
            SLOT(slotToggleSelectionClicked()));

    d->mFullScreenButton = new ContextBarButton("view-fullscreen");
    connect(d->mFullScreenButton, SIGNAL(clicked()),
            SLOT(slotFullScreenClicked()));

    d->mRotateLeftButton = new ContextBarButton("object-rotate-left");
    connect(d->mRotateLeftButton, SIGNAL(clicked()),
            SLOT(slotRotateLeftClicked()));

    d->mRotateRightButton = new ContextBarButton("object-rotate-right");
    connect(d->mRotateRightButton, SIGNAL(clicked()),
            SLOT(slotRotateRightClicked()));

    QHBoxLayout* layout = new QHBoxLayout(d->mContextBar);
    layout->setMargin(2);
    layout->setSpacing(2);
    layout->addWidget(d->mToggleSelectionButton);
    layout->addWidget(d->mFullScreenButton);
    layout->addWidget(d->mRotateLeftButton);
    layout->addWidget(d->mRotateRightButton);

    // Save button
    d->mSaveButton = new ContextBarButton("document-save", d->mView->viewport());
    d->mSaveButton->hide();
    connect(d->mSaveButton, SIGNAL(clicked()),
            SLOT(slotSaveClicked()));
}

PreviewItemDelegate::~PreviewItemDelegate()
{
    delete d;
}

QSize PreviewItemDelegate::sizeHint(const QStyleOptionViewItem & /*option*/, const QModelIndex & /*index*/) const
{
    return d->mView->gridSize();
}

bool PreviewItemDelegate::eventFilter(QObject* object, QEvent* event)
{
    if (object == d->mView->viewport()) {
        switch (event->type()) {
        case QEvent::ToolTip:
            return true;

        case QEvent::HoverMove:
        case QEvent::HoverLeave:
            return d->hoverEventFilter(static_cast<QHoverEvent*>(event));

        case QEvent::MouseButtonPress:
        case QEvent::MouseButtonRelease:
            return d->mouseButtonEventFilter(event->type());

        default:
            return false;
        }
    } else {
        // Necessary for the item editor to work correctly (especially closing
        // the editor with the Escape key)
        return QItemDelegate::eventFilter(object, event);
    }
}

void PreviewItemDelegate::paint(QPainter * painter, const QStyleOptionViewItem & option, const QModelIndex & index) const
{
    int thumbnailHeight = d->mThumbnailSize.height();
    QSize fullSize;
    QPixmap thumbnailPix = d->mView->thumbnailForIndex(index, &fullSize);
    const KFileItem fileItem = fileItemForIndex(index);
    const bool opaque = !thumbnailPix.hasAlphaChannel();
    const bool isDir = fileItem.isDir();
    QRect rect = option.rect;
    const bool selected = option.state & QStyle::State_Selected;
    const bool underMouse = option.state & QStyle::State_MouseOver;
    const QWidget* viewport = d->mView->viewport();

#ifdef DEBUG_DRAW_BORDER
    painter->setPen(Qt::red);
    painter->setBrush(Qt::NoBrush);
    painter->drawRect(rect);
#endif

    // Select color group
    QPalette::ColorGroup cg;

    if ((option.state & QStyle::State_Enabled) && (option.state & QStyle::State_Active)) {
        cg = QPalette::Normal;
    } else if ((option.state & QStyle::State_Enabled)) {
        cg = QPalette::Inactive;
    } else {
        cg = QPalette::Disabled;
    }

    // Select colors
    QColor bgColor, borderColor, fgColor;
    if (selected || underMouse) {
        bgColor = option.palette.color(cg, QPalette::Highlight);
        borderColor = bgColor.dark(SELECTION_BORDER_DARKNESS);
    } else {
        bgColor = viewport->palette().color(viewport->backgroundRole());
        borderColor = bgColor.light(200);
    }
    fgColor = viewport->palette().color(viewport->foregroundRole());

    // Compute thumbnailRect
    QRect thumbnailRect = QRect(
                              rect.left() + (rect.width() - thumbnailPix.width()) / 2,
                              rect.top() + (thumbnailHeight - thumbnailPix.height()) + ITEM_MARGIN,
                              thumbnailPix.width(),
                              thumbnailPix.height());

    // Draw background
    const QRect backgroundRect = thumbnailRect.adjusted(-ITEM_MARGIN, -ITEM_MARGIN, ITEM_MARGIN, ITEM_MARGIN);
    if (selected) {
        d->drawBackground(painter, backgroundRect, bgColor, borderColor);
    } else if (underMouse) {
        painter->setOpacity(0.2);
        d->drawBackground(painter, backgroundRect, bgColor, borderColor);
        painter->setOpacity(1.);
    } else if (opaque) {
        d->drawShadow(painter, thumbnailRect);
    }

    // Draw thumbnail
    if (opaque) {
        painter->setPen(borderColor);
        painter->setRenderHint(QPainter::Antialiasing, false);
        QRect borderRect = thumbnailRect.adjusted(-1, -1, 0, 0);
        painter->drawRect(borderRect);
    }
    painter->drawPixmap(thumbnailRect.left(), thumbnailRect.top(), thumbnailPix);

    // Draw modified indicator
    bool isModified = d->mView->isModified(index);
    if (isModified) {
        // Draws a pixmap of the save button frame, as an indicator that
        // the image has been modified
        QPoint framePosition = d->saveButtonPosition(rect);
        d->initSaveButtonPixmap();
        painter->drawPixmap(framePosition, d->mSaveButtonPixmap);
    }

    // Draw busy indicator
    if (d->mView->isBusy(index)) {
        QPixmap pix = d->mView->busySequenceCurrentPixmap();
        painter->drawPixmap(
            thumbnailRect.left() + (thumbnailRect.width() - pix.width()) / 2,
            thumbnailRect.top() + (thumbnailRect.height() - pix.height()) / 2,
            pix);
    }

    if (index == d->mIndexUnderCursor) {
        // Show bar again: if the thumbnail has changed, we may need to update
        // its position. Don't do it if we are over rotate buttons, though: it
        // would not be nice to move the button now, the user may want to
        // rotate the image one more time.
        // The button will get moved when the mouse leaves.
        if (!d->mRotateLeftButton->underMouse() && !d->mRotateRightButton->underMouse()) {
            d->showContextBar(rect, thumbnailPix);
        }
        if (isModified) {
            // If we just rotated the image with the buttons from the
            // button frame, we need to show the save button frame right now.
            d->showSaveButton(rect);
        } else {
            d->mSaveButton->hide();
        }
    }

    QRect textRect(
        rect.left() + ITEM_MARGIN,
        rect.top() + 2 * ITEM_MARGIN + thumbnailHeight,
        rect.width() - 2 * ITEM_MARGIN,
        d->mView->fontMetrics().height());
    if (isDir || (d->mDetails & PreviewItemDelegate::FileNameDetail)) {
        d->drawText(painter, textRect, fgColor, index.data().toString());
        textRect.moveTop(textRect.bottom());
    }

    if (!isDir && (d->mDetails & PreviewItemDelegate::DateDetail)) {
        const QDateTime dt = TimeUtils::dateTimeForFileItem(fileItem);
        d->drawText(painter, textRect, fgColor, KGlobal::locale()->formatDateTime(dt));
        textRect.moveTop(textRect.bottom());
    }

    if (!isDir && (d->mDetails & PreviewItemDelegate::ImageSizeDetail)) {
        if (fullSize.isValid()) {
            const QString text = QString("%1x%2").arg(fullSize.width()).arg(fullSize.height());
            d->drawText(painter, textRect, fgColor, text);
            textRect.moveTop(textRect.bottom());
        }
    }

    if (!isDir && (d->mDetails & PreviewItemDelegate::FileSizeDetail)) {
        const KIO::filesize_t size = fileItem.size();
        if (size > 0) {
            const QString st = KIO::convertSize(size);
            d->drawText(painter, textRect, fgColor, st);
            textRect.moveTop(textRect.bottom());
        }
    }

#ifdef DEBUG_DRAW_CURRENT
    if (d->mView->currentIndex() == index) {
        painter->fillRect(rect.left(), rect.top(), 12, 12, Qt::red);
    }
#endif
}

void PreviewItemDelegate::setThumbnailSize(const QSize& value)
{
    d->mThumbnailSize = value;
    d->updateViewGridSize();
    d->updateContextBar();
    d->mElidedTextCache.clear();
}

void PreviewItemDelegate::slotSaveClicked()
{
    saveDocumentRequested(urlForIndex(d->mIndexUnderCursor));
}

void PreviewItemDelegate::slotRotateLeftClicked()
{
    d->selectIndexUnderCursorIfNoMultiSelection();
    rotateDocumentLeftRequested(urlForIndex(d->mIndexUnderCursor));
}

void PreviewItemDelegate::slotRotateRightClicked()
{
    d->selectIndexUnderCursorIfNoMultiSelection();
    rotateDocumentRightRequested(urlForIndex(d->mIndexUnderCursor));
}

void PreviewItemDelegate::slotFullScreenClicked()
{
    showDocumentInFullScreenRequested(urlForIndex(d->mIndexUnderCursor));
}

void PreviewItemDelegate::slotToggleSelectionClicked()
{
    d->mView->selectionModel()->select(d->mIndexUnderCursor, QItemSelectionModel::Toggle);
    d->updateToggleSelectionButton();
}

PreviewItemDelegate::ThumbnailDetails PreviewItemDelegate::thumbnailDetails() const
{
    return d->mDetails;
}

void PreviewItemDelegate::setThumbnailDetails(PreviewItemDelegate::ThumbnailDetails details)
{
    d->mDetails = details;
    d->updateViewGridSize();
    d->mView->scheduleDelayedItemsLayout();
}

PreviewItemDelegate::ContextBarActions PreviewItemDelegate::contextBarActions() const
{
    return d->mContextBarActions;
}

void PreviewItemDelegate::setContextBarActions(PreviewItemDelegate::ContextBarActions actions)
{
    d->mContextBarActions = actions;
    d->updateContextBar();
}

Qt::TextElideMode PreviewItemDelegate::textElideMode() const
{
    return d->mTextElideMode;
}

void PreviewItemDelegate::setTextElideMode(Qt::TextElideMode mode)
{
    if (d->mTextElideMode == mode) {
        return;
    }
    d->mTextElideMode = mode;
    d->mElidedTextCache.clear();
    d->mView->viewport()->update();
}

void PreviewItemDelegate::slotRowsChanged()
{
    // We need to update hover ui because the current index may have
    // disappeared: for example if the current image is removed with "del".
    QPoint pos = d->mView->viewport()->mapFromGlobal(QCursor::pos());
    QModelIndex index = d->mView->indexAt(pos);
    d->updateHoverUi(index);
}

QWidget * PreviewItemDelegate::createEditor(QWidget* parent, const QStyleOptionViewItem& /*option*/, const QModelIndex& /*index*/) const
{
    return new ItemEditor(parent);
}

void PreviewItemDelegate::setEditorData(QWidget* widget, const QModelIndex& index) const
{
    ItemEditor* edit = qobject_cast<ItemEditor*>(widget);
    if (!edit) {
        return;
    }
    edit->setText(index.data().toString());
}

void PreviewItemDelegate::updateEditorGeometry(QWidget* widget, const QStyleOptionViewItem& option, const QModelIndex& index) const
{
    ItemEditor* edit = qobject_cast<ItemEditor*>(widget);
    if (!edit) {
        return;
    }
    QString text = index.data().toString();
    int textWidth = edit->fontMetrics().width("  " + text + "  ");
    QRect textRect(
        option.rect.left() + (option.rect.width() - textWidth) / 2,
        option.rect.top() + 2 * ITEM_MARGIN + d->mThumbnailSize.height(),
        textWidth,
        edit->sizeHint().height());

    edit->setGeometry(textRect);
}

void PreviewItemDelegate::setModelData(QWidget* widget, QAbstractItemModel* model, const QModelIndex& index) const
{
    ItemEditor* edit = qobject_cast<ItemEditor*>(widget);
    if (!edit) {
        return;
    }
    if (index.data().toString() != edit->text()) {
        model->setData(index, edit->text(), Qt::EditRole);
    }
}

} // namespace