source: trunk/examples/itemviews/chart/pieview.cpp@ 664

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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