QwtScaleTransformation Class Reference

#include <qwt_scale_map.h>

List of all members.

Public Types
enum	Type {   Linear,   Log10,   Other }

Public Member Functions
	QwtScaleTransformation (Type type)
virtual	~QwtScaleTransformation ()
virtual QwtScaleTransformation *	copy () const
virtual double	invXForm (double x, double p1, double p2, double s1, double s2) const
Type	type () const
virtual double	xForm (double x, double s1, double s2, double p1, double p2) const

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Detailed Description

Operations for linear or logarithmic (base 10) transformations.

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Member Function Documentation

double QwtScaleTransformation::invXForm ( double  p, double  p1, double  p2, double  s1, double  s2  ) 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 ( double  s, double  s1, double  s2, double  p1, double  p2  ) 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);