pieview.cpp

qt-x11-opensource-src-4.1.4.tar.gz源码

/****************************************************************************
**
** Copyright (C) 2004-2006 Trolltech ASA. All rights reserved.
**
** This file is part of the example classes of the Qt Toolkit.
**
** This file may be used under the terms of the GNU General Public
** License version 2.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of
** this file.  Please review the following information to ensure GNU
** General Public Licensing requirements will be met:
** http://www.trolltech.com/products/qt/opensource.html
**
** If you are unsure which license is appropriate for your use, please
** review the following information:
** http://www.trolltech.com/products/qt/licensing.html or contact the
** sales department at [e-mail].
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** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
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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;
}

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::mouseReleaseEvent(QMouseEvent *event)
{
    QAbstractItemView::mouseReleaseEvent(event);
    selectionRect = QRect();
    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();