QwtScaleTransformation Class Reference

A transformation between coordinate systems. More...

#include <qwt_scale_map.h>

List of all members.

Public Types

enum  Type {
  Linear,
  Log10,
  Other
}

Public Member Functions

virtual QwtScaleTransformationcopy () 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

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.


Member Enumeration Documentation

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.


Constructor & Destructor Documentation

QwtScaleTransformation::QwtScaleTransformation ( Type  type  ) 

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 ( 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);


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