qwt_polar_fitter.cpp

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/* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
 * QwtPolar Widget Library
 * Copyright (C) 2008   Uwe Rathmann
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the Qwt License, Version 1.0
 *****************************************************************************/

#include "qwt_polar_fitter.h"
#include <qpolygon.h>
#include <qpainterpath.h>

class QwtPolarFitter::PrivateData
{
public:
    PrivateData():
        stepCount( 5 )
    {
    }

    int stepCount;
};

QwtPolarFitter::QwtPolarFitter( int stepCount )
    : QwtCurveFitter( QwtPolarFitter::Polygon )
{
    d_data = new PrivateData;
    d_data->stepCount = stepCount;
}

QwtPolarFitter::~QwtPolarFitter()
{
    delete d_data;
}

void QwtPolarFitter::setStepCount( int stepCount )
{
    d_data->stepCount = qMax( stepCount, 0 );
}

int QwtPolarFitter::stepCount() const
{
    return d_data->stepCount;
}

QPolygonF QwtPolarFitter::fitCurve( const QPolygonF &points ) const
{
    if ( d_data->stepCount <= 0 || points.size() <= 1 )
        return points;

    QPolygonF fittedPoints;

    int numPoints = points.size() + ( points.size() - 1 ) * d_data->stepCount;

    fittedPoints.resize( numPoints );

    int index = 0;
    fittedPoints[index++] = points[0];
    for ( int i = 1; i < points.size(); i++ )
    {
        const QPointF &p1 = points[i-1];
        const QPointF &p2 = points[i];

        const double dx = ( p2.x() - p1.x() ) / d_data->stepCount;
        const double dy = ( p2.y() - p1.y() ) / d_data->stepCount;
        for ( int j = 1; j <= d_data->stepCount; j++ )
        {
            const double x = p1.x() + j * dx;
            const double y = p1.y() + j * dy;

            fittedPoints[index++] = QPointF( x, y );
        }
    }
    fittedPoints.resize( index );

    return fittedPoints;
}

QPainterPath QwtPolarFitter::fitCurvePath( const QPolygonF &points ) const
{
    QPainterPath path;
    path.addPolygon( fitCurve( points ) );
    return path;
}