pieview.cpp

QT 开发环境里面一个很重要的文件

        case MoveDown:
            if (current.row() < rows(current) - 1)
                current = model()->index(current.row() + 1, current.column(),
                                         rootIndex());
            else
                current = model()->index(rows(current) - 1, current.column(),
                                         rootIndex());
            break;
        default:
            break;
    }

    viewport()->update();
    return current;
}

void PieView::paintEvent(QPaintEvent *event)
{
    QItemSelectionModel *selections = selectionModel();
    QStyleOptionViewItem option = viewOptions();
    QStyle::State state = option.state;

    QBrush background = option.palette.base();
    QPen foreground(option.palette.color(QPalette::WindowText));
    QPen textPen(option.palette.color(QPalette::Text));
    QPen highlightedPen(option.palette.color(QPalette::HighlightedText));

    QPainter painter(viewport());
    painter.setRenderHint(QPainter::Antialiasing);

    painter.fillRect(event->rect(), background);
    painter.setPen(foreground);

    // Viewport rectangles
    QRect pieRect = QRect(margin, margin, pieSize, pieSize);
    QPoint keyPoint = QPoint(totalSize - horizontalScrollBar()->value(),
                             margin - verticalScrollBar()->value());

    if (validItems > 0) {

        painter.save();
        painter.translate(pieRect.x() - horizontalScrollBar()->value(),
                          pieRect.y() - verticalScrollBar()->value());
        painter.drawEllipse(0, 0, pieSize, pieSize);
        double startAngle = 0.0;
        int row;

        for (row = 0; row < model()->rowCount(rootIndex()); ++row) {

            QModelIndex index = model()->index(row, 1, rootIndex());
            double value = model()->data(index).toDouble();

            if (value > 0.0) {
                double angle = 360*value/totalValue;

                QModelIndex colorIndex = model()->index(row, 0, rootIndex());
                QColor color = QColor(model()->data(colorIndex,
                                Qt::DecorationRole).toString());

                if (currentIndex() == index)
                    painter.setBrush(QBrush(color, Qt::Dense4Pattern));
                else if (selections->isSelected(index))
                    painter.setBrush(QBrush(color, Qt::Dense3Pattern));
                else
                    painter.setBrush(QBrush(color));

                painter.drawPie(0, 0, pieSize, pieSize, int(startAngle*16),
                                int(angle*16));

                startAngle += angle;
            }
        }
        painter.restore();

        int keyNumber = 0;

        for (row = 0; row < model()->rowCount(rootIndex()); ++row) {

            QModelIndex index = model()->index(row, 1, rootIndex());
            double value = model()->data(index).toDouble();

            if (value > 0.0) {
                QModelIndex labelIndex = model()->index(row, 0, rootIndex());

                QStyleOptionViewItem option = viewOptions();
                option.rect = visualRect(labelIndex);
                if (selections->isSelected(labelIndex))
                    option.state |= QStyle::State_Selected;
                if (currentIndex() == labelIndex)
                    option.state |= QStyle::State_HasFocus;
                itemDelegate()->paint(&painter, option, labelIndex);

                keyNumber++;
            }
        }
    }
}

void PieView::resizeEvent(QResizeEvent * /* event */)
{
    updateGeometries();
}

int PieView::rows(const QModelIndex &index) const
{
    return model()->rowCount(model()->parent(index));
}

void PieView::rowsInserted(const QModelIndex &parent, int start, int end)
{
    for (int row = start; row <= end; ++row) {

        QModelIndex index = model()->index(row, 1, rootIndex());
        double value = model()->data(index).toDouble();

        if (value > 0.0) {
            totalValue += value;
            validItems++;
        }
    }

    QAbstractItemView::rowsInserted(parent, start, end);
}

void PieView::rowsAboutToBeRemoved(const QModelIndex &parent, int start, int end)
{
    for (int row = start; row <= end; ++row) {

        QModelIndex index = model()->index(row, 1, rootIndex());
        double value = model()->data(index).toDouble();
        if (value > 0.0) {
            totalValue -= value;
            validItems--;
        }
    }

    QAbstractItemView::rowsAboutToBeRemoved(parent, start, end);
}

void PieView::scrollContentsBy(int dx, int dy)
{
    viewport()->scroll(dx, dy);
}

void PieView::scrollTo(const QModelIndex &index, ScrollHint)
{
    QRect area = viewport()->rect();
    QRect rect = visualRect(index);

    if (rect.left() < area.left())
        horizontalScrollBar()->setValue(
            horizontalScrollBar()->value() + rect.left() - area.left());
    else if (rect.right() > area.right())
        horizontalScrollBar()->setValue(
            horizontalScrollBar()->value() + qMin(
                rect.right() - area.right(), rect.left() - area.left()));

    if (rect.top() < area.top())
        verticalScrollBar()->setValue(
            verticalScrollBar()->value() + rect.top() - area.top());
    else if (rect.bottom() > area.bottom())
        verticalScrollBar()->setValue(
            verticalScrollBar()->value() + qMin(
                rect.bottom() - area.bottom(), rect.top() - area.top()));

    update();
}

/*
    Find the indices corresponding to the extent of the selection.
*/

void PieView::setSelection(const QRect &rect, QItemSelectionModel::SelectionFlags command)
{
    // Use content widget coordinates because we will use the itemRegion()
    // function to check for intersections.

    QRect contentsRect = rect.translated(
                            horizontalScrollBar()->value(),
                            verticalScrollBar()->value()).normalized();

    int rows = model()->rowCount(rootIndex());
    int columns = model()->columnCount(rootIndex());
    QModelIndexList indexes;

    for (int row = 0; row < rows; ++row) {
        for (int column = 0; column < columns; ++column) {
            QModelIndex index = model()->index(row, column, rootIndex());
            QRegion region = itemRegion(index);
            if (!region.intersect(contentsRect).isEmpty())
                indexes.append(index);
        }
    }

    if (indexes.size() > 0) {
        int firstRow = indexes[0].row();
        int lastRow = indexes[0].row();
        int firstColumn = indexes[0].column();
        int lastColumn = indexes[0].column();

        for (int i = 1; i < indexes.size(); ++i) {
            firstRow = qMin(firstRow, indexes[i].row());
            lastRow = qMax(lastRow, indexes[i].row());
            firstColumn = qMin(firstColumn, indexes[i].column());
            lastColumn = qMax(lastColumn, indexes[i].column());
        }

        QItemSelection selection(
            model()->index(firstRow, firstColumn, rootIndex()),
            model()->index(lastRow, lastColumn, rootIndex()));
        selectionModel()->select(selection, command);
    } else {
        QModelIndex noIndex;
        QItemSelection selection(noIndex, noIndex);
        selectionModel()->select(selection, command);
    }

    update();
}

void PieView::updateGeometries()
{
    horizontalScrollBar()->setPageStep(viewport()->width());
    horizontalScrollBar()->setRange(0, qMax(0, 2*totalSize - viewport()->width()));
    verticalScrollBar()->setPageStep(viewport()->height());
    verticalScrollBar()->setRange(0, qMax(0, totalSize - viewport()->height()));
}

int PieView::verticalOffset() const
{
    return verticalScrollBar()->value();
}

/*
    Returns the position of the item in viewport coordinates.
*/

QRect PieView::visualRect(const QModelIndex &index) const
{
    QRect rect = itemRect(index);
    if (rect.isValid())
        return QRect(rect.left() - horizontalScrollBar()->value(),
                     rect.top() - verticalScrollBar()->value(),
                     rect.width(), rect.height());
    else
        return rect;
}

/*
    Returns a region corresponding to the selection in viewport coordinates.
*/

QRegion PieView::visualRegionForSelection(const QItemSelection &selection) const
{
    int ranges = selection.count();

    if (ranges == 0)
        return QRect();

    QRegion region;
    for (int i = 0; i < ranges; ++i) {
        QItemSelectionRange range = selection.at(i);
        for (int row = range.top(); row <= range.bottom(); ++row) {
            for (int col = range.left(); col <= range.right(); ++col) {
                QModelIndex index = model()->index(row, col, rootIndex());
                region += visualRect(index);
            }
        }
    }
    return region;
}