QwtTransform - A transformation between coordinate systems.

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Version 6.1.4                                    Wed Jan 2 2019                                  QwtTransform(3)

       A transformation between coordinate systems.

       QwtTransform manipulates values, when being mapped between the scale and the paint device coordinate
       system.

       A transformation consists of 2 methods:

       • transform

       • invTransform

       where one is is the inverse function of the other.

       When  p1,  p2  are the boundaries of the paint device coordinates and s1, s2 the boundaries of the scale,
       QwtScaleMap uses the following calculations:

       • p = p1 + ( p2 - p1 ) * ( T( s ) - T( s1 ) / ( T( s2 ) - T( s1 ) );

       • s = invT ( T( s1 ) + ( T( s2 ) - T( s1 ) ) * ( p - p1 ) / ( p2 - p1 ) );

doubleQwtTransform::bounded(doublevalue)const[virtual]
       Modify value to be a valid value for the transformation. The default implementation does nothing.

       Parameters:value Value to be bounded

       Returns:
           value unmodified

       Reimplemented in QwtLogTransform.

   virtualdoubleQwtTransform::invTransform(doublevalue)const[purevirtual]
       Inverse transformation function

       Parameters:value Value

       Returns:
           Modified value

       Seealso:transform()

       Implemented in QwtPowerTransform, QwtLogTransform, and QwtNullTransform.

   virtualdoubleQwtTransform::transform(doublevalue)const[purevirtual]
       Transformation function

       Parameters:value Value

       Returns:
           Modified value

       Seealso:invTransform()

       Implemented in QwtPowerTransform, QwtLogTransform, and QwtNullTransform.

       QwtTransform - A transformation between coordinate systems.

       #include <qwt_transform.h>

       Inherited by QwtLogTransform, QwtNullTransform, and QwtPowerTransform.

   PublicMemberFunctionsQwtTransform ()
           Constructor.
       virtual ~QwtTransform ()
           Destructor.
       virtual double bounded (double value) const
       virtual double transform (double value) const =0
       virtual double invTransform (double value) const =0
       virtual QwtTransform * copy () const =0
           Virtualized copy operation.