NAME

       QwtAbstractScale - An abstract base class for widgets having a scale.

SYNOPSIS

       #include <qwt_abstract_scale.h>

       Inherits QWidget.

       Inherited by QwtAbstractSlider, and QwtThermo.

   Public Member Functions
       QwtAbstractScale (QWidget *parent=NULL)
       virtual ~QwtAbstractScale ()
           Destructor.
       void setScale (double lowerBound, double upperBound)
           Specify a scale.
       void setScale (const QwtInterval &)
           Specify a scale.
       void setScale (const QwtScaleDiv &)
           Specify a scale.
       const QwtScaleDiv & scaleDiv () const
       void setLowerBound (double value)
       double lowerBound () const
       void setUpperBound (double value)
       double upperBound () const
       void setScaleStepSize (double stepSize)
           Set the step size used for calculating a scale division.
       double scaleStepSize () const
       void setScaleMaxMajor (int ticks)
           Set the maximum number of major tick intervals.
       int scaleMaxMinor () const
       void setScaleMaxMinor (int ticks)
           Set the maximum number of minor tick intervals.
       int scaleMaxMajor () const
       void setScaleEngine (QwtScaleEngine *)
           Set a scale engine.
       const QwtScaleEngine * scaleEngine () const
       QwtScaleEngine * scaleEngine ()
       int transform (double) const
       double invTransform (int) const
       bool isInverted () const
       double minimum () const
       double maximum () const
       const QwtScaleMap & scaleMap () const

   Protected Member Functions
       void rescale (double lowerBound, double upperBound, double stepSize)
       void setAbstractScaleDraw (QwtAbstractScaleDraw *)
           Set a scale draw.
       const QwtAbstractScaleDraw * abstractScaleDraw () const
       QwtAbstractScaleDraw * abstractScaleDraw ()
       virtual void scaleChange ()
           Notify changed scale.

Detailed Description

       An abstract base class for widgets having a scale.

       The scale of an QwtAbstractScale is determined by a QwtScaleDiv definition, that contains
       the boundaries and the ticks of the scale. The scale is painted using a QwtScaleDraw
       object.

       The scale division might be assigned explicitly - but usually it is calculated from the
       boundaries using a QwtScaleEngine.

       The scale engine also decides the type of transformation of the scale ( linear,
       logarithmic ... ).

Constructor & Destructor Documentation

   QwtAbstractScale::QwtAbstractScale (QWidget * parent = NULL)
       Constructor

       Parameters:
           parent Parent widget

       Creates a default QwtScaleDraw and a QwtLinearScaleEngine. The initial scale boundaries
       are set to [ 0.0, 100.0 ]

       The scaleStepSize() is initialized to 0.0, scaleMaxMajor() to 5 and scaleMaxMajor to 3.

Member Function Documentation

   const QwtAbstractScaleDraw * QwtAbstractScale::abstractScaleDraw () const [protected]
       Returns:
           Scale draw

       See also:
           setAbstractScaleDraw()

   QwtAbstractScaleDraw * QwtAbstractScale::abstractScaleDraw () [protected]
       Returns:
           Scale draw

       See also:
           setAbstractScaleDraw()

   double QwtAbstractScale::invTransform (int value) const
       Translate a widget coordinate into a scale value

       Parameters:
           value Widget coordinate

       Returns:
           Corresponding scale coordinate for value

       See also:
           scaleMap(), transform()

   bool QwtAbstractScale::isInverted () const
       Returns:
           True, when the scale is increasing in opposite direction to the widget coordinates

   double QwtAbstractScale::lowerBound () const
       Returns:
           Lower bound of the scale

       See also:
           setLowerBound(), setScale(), upperBound()

   double QwtAbstractScale::maximum () const
       Returns:
           The boundary with the larger value

       See also:
           minimum(), lowerBound(), upperBound()

   double QwtAbstractScale::minimum () const
       Returns:
           The boundary with the smaller value

       See also:
           maximum(), lowerBound(), upperBound()

   void QwtAbstractScale::rescale (double lowerBound, double upperBound, double stepSize)
       [protected]
       Recalculate the scale division and update the scale.

       Parameters:
           lowerBound Lower limit of the scale interval
           upperBound Upper limit of the scale interval
           stepSize Major step size

       See also:
           scaleChange()

   const QwtScaleDiv & QwtAbstractScale::scaleDiv () const
       Returns:
           Scale boundaries and positions of the ticks

       The scale division might have been assigned explicitly or calculated implicitly by
       rescale().

   const QwtScaleEngine * QwtAbstractScale::scaleEngine () const
       Returns:
           Scale engine

       See also:
           setScaleEngine()

   QwtScaleEngine * QwtAbstractScale::scaleEngine ()
       Returns:
           Scale engine

       See also:
           setScaleEngine()

   const QwtScaleMap & QwtAbstractScale::scaleMap () const
       Returns:
           Map to translate between scale and widget coordinates

   int QwtAbstractScale::scaleMaxMajor () const
       Returns:
           Maximal number of major tick intervals

       See also:
           setScaleMaxMajor(), scaleMaxMinor()

   int QwtAbstractScale::scaleMaxMinor () const
       Returns:
           Maximal number of minor tick intervals

       See also:
           setScaleMaxMinor(), scaleMaxMajor()

   double QwtAbstractScale::scaleStepSize () const
       Returns:
           Hint for the step size of the scale

       See also:
           setScaleStepSize(), QwtScaleEngine::divideScale()

   void QwtAbstractScale::setAbstractScaleDraw (QwtAbstractScaleDraw * scaleDraw) [protected]
       Set a scale draw. scaleDraw has to be created with new and will be deleted in the
       destructor or the next call of setAbstractScaleDraw().

       See also:
           abstractScaleDraw()

   void QwtAbstractScale::setLowerBound (double value)
       Set the lower bound of the scale

       Parameters:
           value Lower bound

       See also:
           lowerBound(), setScale(), setUpperBound()

       Note:
           For inverted scales the lower bound is greater than the upper bound

   void QwtAbstractScale::setScale (double lowerBound, double upperBound)
       Specify a scale. Define a scale by an interval

       The ticks are calculated using scaleMaxMinor(), scaleMaxMajor() and scaleStepSize().

       Parameters:
           lowerBound lower limit of the scale interval
           upperBound upper limit of the scale interval

       Note:
           For inverted scales the lower bound is greater than the upper bound

   void QwtAbstractScale::setScale (const QwtInterval & interval)
       Specify a scale. Define a scale by an interval

       The ticks are calculated using scaleMaxMinor(), scaleMaxMajor() and scaleStepSize().

       Parameters:
           interval Interval

   void QwtAbstractScale::setScale (const QwtScaleDiv & scaleDiv)
       Specify a scale. scaleMaxMinor(), scaleMaxMajor() and scaleStepSize() and have no effect.

       Parameters:
           scaleDiv Scale division

       See also:
           setAutoScale()

   void QwtAbstractScale::setScaleEngine (QwtScaleEngine * scaleEngine)
       Set a scale engine. The scale engine is responsible for calculating the scale division and
       provides a transformation between scale and widget coordinates.

       scaleEngine has to be created with new and will be deleted in the destructor or the next
       call of setScaleEngine.

   void QwtAbstractScale::setScaleMaxMajor (int ticks)
       Set the maximum number of major tick intervals. The scale's major ticks are calculated
       automatically such that the number of major intervals does not exceed ticks.

       The default value is 5.

       Parameters:
           ticks Maximal number of major ticks.

       See also:
           scaleMaxMajor(), setScaleMaxMinor(), setScaleStepSize(),
           QwtScaleEngine::divideInterval()

   void QwtAbstractScale::setScaleMaxMinor (int ticks)
       Set the maximum number of minor tick intervals. The scale's minor ticks are calculated
       automatically such that the number of minor intervals does not exceed ticks. The default
       value is 3.

       Parameters:
           ticks Maximal number of minor ticks.

       See also:
           scaleMaxMajor(), setScaleMaxMinor(), setScaleStepSize(),
           QwtScaleEngine::divideInterval()

   void QwtAbstractScale::setScaleStepSize (double stepSize)
       Set the step size used for calculating a scale division. The step size is hint for
       calculating the intervals for the major ticks of the scale. A value of 0.0 is interpreted
       as no hint.

       Parameters:
           stepSize Hint for the step size of the scale

       See also:
           scaleStepSize(), QwtScaleEngine::divideScale()

       Note:
           Position and distance between the major ticks also depends on scaleMaxMajor().

   void QwtAbstractScale::setUpperBound (double value)
       Set the upper bound of the scale

       Parameters:
           value Upper bound

       See also:
           upperBound(), setScale(), setLowerBound()

       Note:
           For inverted scales the lower bound is greater than the upper bound

   int QwtAbstractScale::transform (double value) const
       Translate a scale value into a widget coordinate

       Parameters:
           value Scale value

       Returns:
           Corresponding widget coordinate for value

       See also:
           scaleMap(), invTransform()

   double QwtAbstractScale::upperBound () const
       Returns:
           Upper bound of the scale

       See also:
           setUpperBound(), setScale(), lowerBound()

Author

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