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/* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
* Qwt Widget Library
* Copyright (C) 1997 Josef Wilgen
* Copyright (C) 2002 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 <qstack.h>
#include <qvector.h>
#if QT_VERSION < 0x040601
#define qFabs(x) ::fabs(x)
#endif
//! Constructor
QwtCurveFitter::QwtCurveFitter()
{
}
//! Destructor
QwtCurveFitter::~QwtCurveFitter()
{
}
class QwtSplineCurveFitter::PrivateData
{
public:
PrivateData():
fitMode( QwtSplineCurveFitter::Auto ),
splineSize( 250 )
{
}
QwtSpline spline;
QwtSplineCurveFitter::FitMode fitMode;
int splineSize;
};
QwtSplineCurveFitter::QwtSplineCurveFitter()
{
d_data = new PrivateData;
}
QwtSplineCurveFitter::~QwtSplineCurveFitter()
{
delete d_data;
}
/*!
Select the algorithm used for building the spline
\param mode Mode representing a spline algorithm
\sa fitMode()
*/
void QwtSplineCurveFitter::setFitMode( FitMode mode )
/*!
\return Mode representing a spline algorithm
\sa setFitMode()
*/
QwtSplineCurveFitter::FitMode QwtSplineCurveFitter::fitMode() const
{
return d_data->fitMode;
}
/*!
Assign a spline
\param spline Spline
\sa spline()
*/
void QwtSplineCurveFitter::setSpline( const QwtSpline &spline )
{
d_data->spline = spline;
d_data->spline.reset();
}
const QwtSpline &QwtSplineCurveFitter::spline() const
{
return d_data->spline;
}
QwtSpline &QwtSplineCurveFitter::spline()
/*!
Assign a spline size ( has to be at least 10 points )
\param splineSize Spline size
\sa splineSize()
*/
void QwtSplineCurveFitter::setSplineSize( int splineSize )
int QwtSplineCurveFitter::splineSize() const
{
return d_data->splineSize;
}
/*!
Find a curve which has the best fit to a series of data points
\param points Series of data points
\return Curve points
*/
QPolygonF QwtSplineCurveFitter::fitCurve( const QPolygonF &points ) const
if ( size <= 2 )
return points;
FitMode fitMode = d_data->fitMode;
const QPointF *p = points.data();
for ( int i = 1; i < size; i++ )
{
if ( p[i].x() <= p[i-1].x() )
{
fitMode = ParametricSpline;
break;
}
};
}
if ( fitMode == ParametricSpline )
QPolygonF QwtSplineCurveFitter::fitSpline( const QPolygonF &points ) const
for ( int i = 0; i < d_data->splineSize; i++ )
{
QPointF &p = fittedPoints[i];
}
d_data->spline.reset();
return fittedPoints;
}
QPolygonF QwtSplineCurveFitter::fitParametric( const QPolygonF &points ) const
QPolygonF fittedPoints( d_data->splineSize );
QPolygonF splinePointsX( size );
QPolygonF splinePointsY( size );
const QPointF *p = points.data();
QPointF *spX = splinePointsX.data();
QPointF *spY = splinePointsY.data();
if ( i > 0 )
{
const double delta = qSqrt( qwtSqr( x - spX[i-1].y() )
+ qwtSqr( y - spY[i-1].y() ) );
param += qMax( delta, 1.0 );
spX[i].setX( param );
spX[i].setY( x );
spY[i].setX( param );
spY[i].setY( y );
if ( !d_data->spline.isValid() )
return points;
const double deltaX =
splinePointsX[size - 1].x() / ( d_data->splineSize - 1 );
for ( i = 0; i < d_data->splineSize; i++ )
{
if ( !d_data->spline.isValid() )
return points;
const double deltaY =
splinePointsY[size - 1].x() / ( d_data->splineSize - 1 );
for ( i = 0; i < d_data->splineSize; i++ )
{
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class QwtWeedingCurveFitter::PrivateData
{
public:
PrivateData():
tolerance( 1.0 ),
chunkSize( 0 )
{
}
double tolerance;
uint chunkSize;
};
class QwtWeedingCurveFitter::Line
{
public:
Line( int i1 = 0, int i2 = 0 ):
from( i1 ),
to( i2 )
{
}
int from;
int to;
};
/*!
Constructor
\param tolerance Tolerance
\sa setTolerance(), tolerance()
*/
QwtWeedingCurveFitter::QwtWeedingCurveFitter( double tolerance )
{
d_data = new PrivateData;
setTolerance( tolerance );
}
//! Destructor
QwtWeedingCurveFitter::~QwtWeedingCurveFitter()
{
delete d_data;
}
/*!
Assign the tolerance
The tolerance is the maximum distance, that is acceptable
between the original curve and the smoothed curve.
Increasing the tolerance will reduce the number of the
resulting points.
\param tolerance Tolerance
\sa tolerance()
*/
void QwtWeedingCurveFitter::setTolerance( double tolerance )
{
d_data->tolerance = qMax( tolerance, 0.0 );
}
/*!
\return Tolerance
\sa setTolerance()
*/
double QwtWeedingCurveFitter::tolerance() const
{
return d_data->tolerance;
}
/*!
Limit the number of points passed to a run of the algorithm
The runtime of the Douglas Peucker algorithm increases non linear
with the number of points. For a chunk size > 0 the polygon
is split into pieces passed to the algorithm one by one.
\param numPoints Maximum for the number of points passed to the algorithm
\sa chunkSize()
*/
void QwtWeedingCurveFitter::setChunkSize( uint numPoints )
{
if ( numPoints > 0 )
numPoints = qMax( numPoints, 3U );
d_data->chunkSize = numPoints;
}
/*!
\return Maximum for the number of points passed to a run
of the algorithm - or 0, when unlimited
\sa setChunkSize()
*/
uint QwtWeedingCurveFitter::chunkSize() const
{
return d_data->chunkSize;
}
/*!
\param points Series of data points
\return Curve points
*/
QPolygonF QwtWeedingCurveFitter::fitCurve( const QPolygonF &points ) const
{
QPolygonF fittedPoints;
if ( d_data->chunkSize == 0 )
{
fittedPoints = simplify( points );
}
else
{
for ( int i = 0; i < points.size(); i += d_data->chunkSize )
{
const QPolygonF p = points.mid( i, d_data->chunkSize );
fittedPoints += simplify( p );
}
}
return fittedPoints;
}
QPolygonF QwtWeedingCurveFitter::simplify( const QPolygonF &points ) const
{
const double toleranceSqr = d_data->tolerance * d_data->tolerance;
QStack<Line> stack;
stack.reserve( 500 );
const QPointF *p = points.data();
const int nPoints = points.size();
QVector<bool> usePoint( nPoints, false );
stack.push( Line( 0, nPoints - 1 ) );
while ( !stack.isEmpty() )
{
const Line r = stack.pop();
// initialize line segment
const double vecX = p[r.to].x() - p[r.from].x();
const double vecY = p[r.to].y() - p[r.from].y();
const double vecLength = qSqrt( vecX * vecX + vecY * vecY );
const double unitVecX = ( vecLength != 0.0 ) ? vecX / vecLength : 0.0;
const double unitVecY = ( vecLength != 0.0 ) ? vecY / vecLength : 0.0;
double maxDistSqr = 0.0;
int nVertexIndexMaxDistance = r.from + 1;
for ( int i = r.from + 1; i < r.to; i++ )
{
//compare to anchor
const double fromVecX = p[i].x() - p[r.from].x();
const double fromVecY = p[i].y() - p[r.from].y();
double distToSegmentSqr;
if ( fromVecX * unitVecX + fromVecY * unitVecY < 0.0 )
{
distToSegmentSqr = fromVecX * fromVecX + fromVecY * fromVecY;
}
else
{
const double toVecX = p[i].x() - p[r.to].x();
const double toVecY = p[i].y() - p[r.to].y();
const double toVecLength = toVecX * toVecX + toVecY * toVecY;
const double s = toVecX * ( -unitVecX ) + toVecY * ( -unitVecY );
if ( s < 0.0 )
{
distToSegmentSqr = toVecLength;
}
else
{
distToSegmentSqr = qFabs( toVecLength - s * s );
}
}
if ( maxDistSqr < distToSegmentSqr )
{
maxDistSqr = distToSegmentSqr;
nVertexIndexMaxDistance = i;
}
}
if ( maxDistSqr <= toleranceSqr )
{
usePoint[r.from] = true;
usePoint[r.to] = true;
}
else
{
stack.push( Line( r.from, nVertexIndexMaxDistance ) );
stack.push( Line( nVertexIndexMaxDistance, r.to ) );
}
}
QPolygonF stripped;
for ( int i = 0; i < nPoints; i++ )
{
if ( usePoint[i] )
stripped += p[i];
}
return stripped;
}