QwtScaleTransformation Class Reference

#include <qwt_scale_map.h>

List of all members.

Public Types
enum	Type {   Linear,   Log10,   Other }
Public Member Functions
virtual QwtScaleTransformation *	copy () const
virtual double	invXForm (double p, double p1, double p2, double s1, double s2) const
	QwtScaleTransformation (Type type)
Type	type () const
virtual double	xForm (double s, double s1, double s2, double p1, double p2) const
virtual	~QwtScaleTransformation ()

---

Detailed Description

A transformation between coordinate systems.

QwtScaleTransformation offers transformations from the coordinate system of a scale into the linear coordinate system of a paint device and vice versa.

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Member Enumeration Documentation

enum QwtScaleTransformation::Type

Transformation type.

Enumerator:

Linear	Transformation between 2 linear scales.
Log10	Transformation between a linear and a logarithmic ( base 10 ) scale.
Other	Any other type of transformation.

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Constructor & Destructor Documentation

QwtScaleTransformation::QwtScaleTransformation

(

Type

type

)

Constructor for a linear transformation.

QwtScaleTransformation::~QwtScaleTransformation

(

)

[virtual]

Destructor.

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Member Function Documentation

QwtScaleTransformation * QwtScaleTransformation::copy

(

)

const [virtual]

Create a clone of the transformation.

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);