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#include <math.h>

#include <QtGui>

#ifndef M_PI

#define M_PI 3.1415927

#endif

#include "pieview.h"

PieView::PieView(QWidget *parent)

    : QAbstractItemView(parent)

{

    horizontalScrollBar()->setRange(0, 0);

    verticalScrollBar()->setRange(0, 0);

    margin = 8;

    totalSize = 300;

    pieSize = totalSize - 2*margin;

    validItems = 0;

    totalValue = 0.0;

    rubberBand = 0;

}

void PieView::dataChanged(const QModelIndex &topLeft,

                          const QModelIndex &bottomRight)

{

    QAbstractItemView::dataChanged(topLeft, bottomRight);

    validItems = 0;

    totalValue = 0.0;

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

        QModelIndex index = model()->index(row, 1, rootIndex());

        double value = model()->data(index).toDouble();

        if (value > 0.0) {

            totalValue += value;

            validItems++;

        }

    }

    viewport()->update();

}

bool PieView::edit(const QModelIndex &index, EditTrigger trigger, QEvent *event)

{

    if (index.column() == 0)

        return QAbstractItemView::edit(index, trigger, event);

    else

        return false;

}

/*

    Returns the item that covers the coordinate given in the view.

*/

QModelIndex PieView::indexAt(const QPoint &point) const

{

    if (validItems == 0)

        return QModelIndex();

    // Transform the view coordinates into contents widget coordinates.

    int wx = point.x() + horizontalScrollBar()->value();

    int wy = point.y() + verticalScrollBar()->value();

    if (wx < totalSize) {

        double cx = wx - totalSize/2;

        double cy = totalSize/2 - wy; // positive cy for items above the center

        // Determine the distance from the center point of the pie chart.

        double d = pow(pow(cx, 2) + pow(cy, 2), 0.5);

        if (d == 0 || d > pieSize/2)

            return QModelIndex();

        // Determine the angle of the point.

        double angle = (180 / M_PI) * acos(cx/d);

        if (cy < 0)

            angle = 360 - angle;

        // Find the relevant slice of the pie.

        double startAngle = 0.0;

        for (int 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 sliceAngle = 360*value/totalValue;

                if (angle >= startAngle && angle < (startAngle + sliceAngle))

                    return model()->index(row, 1, rootIndex());

                startAngle += sliceAngle;

            }

        }

    } else {

        double itemHeight = QFontMetrics(viewOptions().font).height();

        int listItem = int((wy - margin) / itemHeight);

        int validRow = 0;

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

            QModelIndex index = model()->index(row, 1, rootIndex());

            if (model()->data(index).toDouble() > 0.0) {

                if (listItem == validRow)

                    return model()->index(row, 0, rootIndex());

                // Update the list index that corresponds to the next valid row.

                validRow++;

            }

        }

    }

    return QModelIndex();

}

bool PieView::isIndexHidden(const QModelIndex & /*index*/) const

{

    return false;

}

/*

    Returns the rectangle of the item at position \a index in the

    model. The rectangle is in contents coordinates.

*/

QRect PieView::itemRect(const QModelIndex &index) const

{

    if (!index.isValid())

        return QRect();

    // Check whether the index's row is in the list of rows represented

    // by slices.

    QModelIndex valueIndex;

    if (index.column() != 1)

        valueIndex = model()->index(index.row(), 1, rootIndex());

    else

        valueIndex = index;

    if (model()->data(valueIndex).toDouble() > 0.0) {

        int listItem = 0;

        for (int row = index.row()-1; row >= 0; --row) {

            if (model()->data(model()->index(row, 1, rootIndex())).toDouble() > 0.0)

                listItem++;

        }

        double itemHeight;

        switch (index.column()) {

        case 0:

            itemHeight = QFontMetrics(viewOptions().font).height();

            return QRect(totalSize,

                         int(margin + listItem*itemHeight),

                         totalSize - margin, int(itemHeight));

        case 1:

            return viewport()->rect();

        }

    }

    return QRect();

}

QRegion PieView::itemRegion(const QModelIndex &index) const

{

    if (!index.isValid())

        return QRegion();

    if (index.column() != 1)

        return itemRect(index);

    if (model()->data(index).toDouble() <= 0.0)

        return QRegion();

    double startAngle = 0.0;

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

        QModelIndex sliceIndex = model()->index(row, 1, rootIndex());

        double value = model()->data(sliceIndex).toDouble();

        if (value > 0.0) {

            double angle = 360*value/totalValue;

            if (sliceIndex == index) {

                QPainterPath slicePath;

                slicePath.moveTo(totalSize/2, totalSize/2);

                slicePath.arcTo(margin, margin, margin+pieSize, margin+pieSize,

                                startAngle, angle);

                slicePath.closeSubpath();

                return QRegion(slicePath.toFillPolygon().toPolygon());

            }

            startAngle += angle;

        }

    }

    return QRegion();

}

int PieView::horizontalOffset() const

{

    return horizontalScrollBar()->value();

}

void PieView::mousePressEvent(QMouseEvent *event)

{

    QAbstractItemView::mousePressEvent(event);

    origin = event->pos();

    if (!rubberBand)

        rubberBand = new QRubberBand(QRubberBand::Rectangle, viewport());

    rubberBand->setGeometry(QRect(origin, QSize()));

    rubberBand->show();

}

void PieView::mouseMoveEvent(QMouseEvent *event)

{

    if (rubberBand)

        rubberBand->setGeometry(QRect(origin, event->pos()).normalized());

    QAbstractItemView::mouseMoveEvent(event);

}

void PieView::mouseReleaseEvent(QMouseEvent *event)

{

    QAbstractItemView::mouseReleaseEvent(event);

    if (rubberBand)

        rubberBand->hide();

    viewport()->update();

}

QModelIndex PieView::moveCursor(QAbstractItemView::CursorAction cursorAction,

                                Qt::KeyboardModifiers /*modifiers*/)

{

    QModelIndex current = currentIndex();

    switch (cursorAction) {

        case MoveLeft:

        case MoveUp:

            if (current.row() > 0)

                current = model()->index(current.row() - 1, current.column(),

                                         rootIndex());

            else

                current = model()->index(0, current.column(), rootIndex());

            break;

        case MoveRight:

        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.

*/