QwtScaleEngine - Base class for scale engines.

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Version 6.1.4                                    Wed Jan 2 2019                                QwtScaleEngine(3)

QwtScaleEngine::QwtScaleEngine(uintbase=10)[explicit]
       Constructor

       Parameters:base Base of the scale engine

       Seealso:setBase()

       Base class for scale engines.

       A scale engine tries to find 'reasonable' ranges and step sizes for scales.

       The layout of the scale can be varied with setAttribute().

       Qwt offers implementations for logarithmic and linear scales.

enumQwtScaleEngine::Attribute
       Layout attributes

       Seealso:setAttribute(), testAttribute(), reference(), lowerMargin(), upperMargin()EnumeratorNoAttribute
              No attributes.

       IncludeReference
              Build a scale which includes the reference() value.

       Symmetric
              Build a scale which is symmetric to the reference() value.

       Floating
              The endpoints of the scale are supposed to be equal the outmost included values plus the specified
              margins  (see  setMargins()).  If  this  attribute  is not set, the endpoints of the scale will be
              integer multiples of the step size.

       Inverted
              Turn the scale upside down.

QwtScaleEngine::AttributesQwtScaleEngine::attributes()constReturns:
           Scale attributes

       Seealso:Attribute, setAttributes(), testAttribute()virtualvoidQwtScaleEngine::autoScale(intmaxNumSteps,double&x1,double&x2,double&stepSize)const[purevirtual]
       Align and divide an interval

       Parameters:maxNumSteps Max. number of steps
           x1 First limit of the interval (In/Out)
           x2 Second limit of the interval (In/Out)
           stepSize Step size (Return value)

       Implemented in QwtLogScaleEngine, QwtLinearScaleEngine, and QwtDateScaleEngine.

   uintQwtScaleEngine::base()constReturns:
           base Base of the scale engine

       Seealso:setBase()QwtIntervalQwtScaleEngine::buildInterval(doublevalue)const[protected]
       Build an interval around a value. In case of v == 0.0 the interval is [-0.5, 0.5], otherwide it is [0.5 *
       v, 1.5 * v]

       Parameters:value Initial value

       Returns:
           Calculated interval

   boolQwtScaleEngine::contains(constQwtInterval&interval,doublevalue)const[protected]
       Check if an interval 'contains' a value

       Parameters:interval Interval
           value Value

       Returns:
           True, when the value is inside the interval

   doubleQwtScaleEngine::divideInterval(doubleintervalSize,intnumSteps)const[protected]
       Calculate a step size for an interval size

       Parameters:intervalSize Interval size
           numSteps Number of steps

       Returns:
           Step size

   virtualQwtScaleDivQwtScaleEngine::divideScale(doublex1,doublex2,intmaxMajorSteps,intmaxMinorSteps,doublestepSize=0.0)const[purevirtual]
       Calculate a scale division.

       Parameters:x1 First interval limit
           x2 Second interval limit
           maxMajorSteps Maximum for the number of major steps
           maxMinorSteps Maximum number of minor steps
           stepSize Step size. If stepSize == 0.0, the scaleEngine calculates one.

       Returns:
           Calculated scale division

       Implemented in QwtLogScaleEngine, QwtLinearScaleEngine, and QwtDateScaleEngine.

   doubleQwtScaleEngine::lowerMargin()constReturns:
           the margin at the lower end of the scale The default margin is 0.

       Seealso:setMargins()doubleQwtScaleEngine::reference()constReturns:
           the reference value

       Seealso:setReference(), setAttribute()voidQwtScaleEngine::setAttribute(Attributeattribute,boolon=true)
       Change a scale attribute

       Parameters:attribute Attribute to change
           on On/Off

       Seealso:Attribute, testAttribute()voidQwtScaleEngine::setAttributes(Attributesattributes)
       Change the scale attribute

       Parameters:attributes Set scale attributes

       Seealso:Attribute, attributes()voidQwtScaleEngine::setBase(uintbase)
       Set the base of the scale engine

       While a base of 10 is what 99.9% of all applications need certain scales might need a different base: f.e
       2

       The default setting is 10

       Parameters:base Base of the engine

       Seealso:base()voidQwtScaleEngine::setMargins(doublelower,doubleupper)
       Specify margins at the scale's endpoints.

       Parameters:lower minimum distance between the scale's lower boundary and the smallest enclosed value
           upper minimum distance between the scale's upper boundary and the greatest enclosed value

       Margins can be used to leave a minimum amount of space between the enclosed intervals and the  boundaries
       of the scale.

       Warning:
           • QwtLogScaleEngine measures the margins in decades.
       Seealso:upperMargin(), lowerMargin()voidQwtScaleEngine::setReference(doublereference)
       Specify a reference point.
       Parameters:reference New reference value
       The  reference  point is needed if options IncludeReference or Symmetric are active. Its default value is
       0.0.
       Seealso:AttributevoidQwtScaleEngine::setTransformation(QwtTransform*transform)
       Assign a transformation
       Parameters:transform Transformation
       The transformation object is used as factory for clones that are returned by transformation()
       The scale engine takes ownership of the transformation.
       Seealso:QwtTransform::copy(), transformation()QList<double>QwtScaleEngine::strip(constQList<double>&ticks,constQwtInterval&interval)const[protected]
       Remove ticks from a list, that are not inside an interval
       Parameters:ticks Tick list
           interval Interval
       Returns:
           Stripped tick list
   boolQwtScaleEngine::testAttribute(Attributeattribute)constReturns:
           True, if attribute is enabled.
       Parameters:attribute Attribute to be tested
       Seealso:Attribute, setAttribute()QwtTransform*QwtScaleEngine::transformation()const
       Create  and  return  a  clone  of  the  transformation  of  the  engine.  When  the engine has no special
       transformation NULL is returned, indicating no transformation.
       Returns:
           A clone of the transfomation
       Seealso:setTransformation()doubleQwtScaleEngine::upperMargin()constReturns:
           the margin at the upper end of the scale The default margin is 0.
       Seealso:setMargins()

       QwtScaleEngine - Base class for scale engines.

       #include <qwt_scale_engine.h>

       Inherited by QwtLinearScaleEngine, and QwtLogScaleEngine.

   PublicTypes
       enum Attribute { NoAttribute = 0x00, IncludeReference = 0x01, Symmetric = 0x02, Floating = 0x04, Inverted
           = 0x08 }
       typedef QFlags< Attribute > Attributes
           Layout attributes.

   PublicMemberFunctionsQwtScaleEngine (uint base=10)
       virtual ~QwtScaleEngine ()
           Destructor.
       void setBase (uint base)
       uint base () const
       void setAttribute (Attribute, bool on=true)
       bool testAttribute (Attribute) const
       void setAttributes (Attributes)
       Attributesattributes () const
       void setReference (double)
           Specify a reference point.
       double reference () const
       void setMargins (double lower, double upper)
           Specify margins at the scale's endpoints.
       double lowerMargin () const
       double upperMargin () const
       virtual void autoScale (int maxNumSteps, double &x1, double &x2, double &stepSize) const =0
       virtual QwtScaleDivdivideScale (double x1, double x2, int maxMajorSteps, int maxMinorSteps, double
           stepSize=0.0) const =0
           Calculate a scale division.
       void setTransformation (QwtTransform *)
       QwtTransform * transformation () const

   ProtectedMemberFunctions
       bool contains (const QwtInterval &, double value) const
       QList< double > strip (const QList< double > &, const QwtInterval &) const
       double divideInterval (double intervalSize, int numSteps) const
       QwtIntervalbuildInterval (double value) const
           Build an interval around a value.