SYNOPSIS

#include <qwt_scale_map.h>

Public Types

enum Type { Linear, Log10, Other }

Public Member Functions

virtual QwtScaleTransformation * copy () const

virtual double invXForm (double x, double p1, double p2, double s1, double s2) const

QwtScaleTransformation (Type type)

Type type () const

virtual double xForm (double x, double s1, double s2, double p1, double p2) const

virtual ~QwtScaleTransformation ()

Detailed Description

Operations for linear or logarithmic (base 10) transformations.

Constructor & Destructor Documentation

QwtScaleTransformation::QwtScaleTransformation (Typetype)

Constructor for a linear transformation.

QwtScaleTransformation::~QwtScaleTransformation () [virtual]

Destructor.

Member Function Documentation

QwtScaleTransformation * QwtScaleTransformation::copy () const [virtual]

Create a clone of the transformation.

double QwtScaleTransformation::invXForm (doublep, doublep1, doublep2, doubles1, doubles2) const [virtual]

Transform a value from the coordinate system of the paint device into the coordinate system of a scale. Parameters:

p Value related to the coordinate system of the paint device
p1 First border of the coordinate system of the paint device
p2 Second border of the coordinate system of the paint device
s1 First border of the coordinate system of the scale
s2 Second border of the coordinate system of the scale

Returns:

linear mapping:

s1 + ( s2 - s1 ) / ( p2 - p1 ) * ( p - p1 );

log10 mapping:

exp((p - p1) / (p2 - p1) * log(s2 / s1)) * s1;

QwtScaleTransformation::Type QwtScaleTransformation::type () const [inline]Returns:

Transformation type

double QwtScaleTransformation::xForm (doubles, doubles1, doubles2, doublep1, doublep2) const [virtual]

Transform a value from the coordinate system of a scale into the coordinate system of the paint device. Parameters:

s Value related to the coordinate system of the scale
s1 First border of the coordinate system of the scale
s2 Second border of the coordinate system of the scale
p1 First border of the coordinate system of the paint device
p2 Second border of the coordinate system of the paint device

Returns:

linear mapping:

p1 + (p2 - p1) / (s2 - s1) * (s - s1);

log10 mapping:

p1 + (p2 - p1) / log(s2 / s1) * log(s / s1);

Author

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