QwtSeriesData< T >(3)          Qwt User's Guide          QwtSeriesData< T >(3)

NAME
       QwtSeriesData< T > - Abstract interface for iterating over samples.


SYNOPSIS
       #include <qwt_series_data.h>

       Inherited by QwtArraySeriesData< QwtIntervalSample >,
       QwtArraySeriesData< QwtVectorFieldSample >, QwtArraySeriesData<
       QwtOHLCSample >, QwtArraySeriesData< QwtSetSample >,
       QwtArraySeriesData< QwtPoint3D >, and QwtArraySeriesData< T >.

   Public Member Functions
       QwtSeriesData ()
           Constructor.
       virtual ~QwtSeriesData ()
           Destructor.
       virtual size_t size () const =0
       virtual T sample (size_t i) const =0
       virtual QRectF boundingRect () const =0
       virtual void setRectOfInterest (const QRectF &rect)

   Protected Attributes
       QRectF cachedBoundingRect
           Can be used to cache a calculated bounding rectangle.

Detailed Description
   template<typename T>
       class QwtSeriesData< T >" Abstract interface for iterating over
       samples.

       Qwt offers several implementations of the QwtSeriesData API, but in
       situations, where data of an application specific format needs to be
       displayed, without having to copy it, it is recommended to implement an
       individual data access.

       A subclass of QwtSeriesData<QPointF> must implement:

       o size()
          Should return number of data points.

       o sample()
          Should return values x and y values of the sample at specific
         position as QPointF object.

       o boundingRect()
          Should return the bounding rectangle of the data series. It is used
         for autoscaling and might help certain algorithms for displaying the
         data. You can use qwtBoundingRect() for an implementation but often
         it is possible to implement a more efficient algorithm depending on
         the characteristics of the series. The member cachedBoundingRect is
         intended for caching the calculated rectangle.

       Definition at line 49 of file qwt_series_data.h.

Member Function Documentation
   template<typename T > virtual QRectF QwtSeriesData< T >::boundingRect ()
       const [pure virtual]
       Calculate the bounding rect of all samples

       The bounding rect is necessary for autoscaling and can be used for a
       couple of painting optimizations.

       qwtBoundingRect(...) offers slow implementations iterating over the
       samples. For large sets it is recommended to implement something faster
       f.e. by caching the bounding rectangle.

       Returns
           Bounding rectangle

       Implemented in QwtTradingChartData, QwtVectorFieldData,
       QwtSetSeriesData, QwtIntervalSeriesData, QwtPoint3DSeriesData,
       QwtPointSeriesData, and QwtSyntheticPointData.

   template<typename T > virtual T QwtSeriesData< T >::sample (size_t i) const
       [pure virtual]
       Return a sample

       Parameters
           i Index

       Returns
           Sample at position i

       Implemented in QwtArraySeriesData< T >, QwtArraySeriesData<
       QwtIntervalSample >, QwtArraySeriesData< QwtVectorFieldSample >,
       QwtArraySeriesData< QwtOHLCSample >, QwtArraySeriesData< QPointF >,
       QwtArraySeriesData< QwtSetSample >, QwtArraySeriesData< QwtPoint3D >,
       QwtSyntheticPointData, QwtCPointerValueData< T >, QwtValuePointData< T
       >, QwtCPointerData< T >, and QwtPointArrayData< T >.

   template<typename T > void QwtSeriesData< T >::setRectOfInterest (const
       QRectF & rect) [virtual]
       Set a the 'rect of interest'

       QwtPlotSeriesItem defines the current area of the plot canvas as
       'rectangle of interest' ( QwtPlotSeriesItem::updateScaleDiv() ). It can
       be used to implement different levels of details.

       The default implementation does nothing.

       Parameters
           rect Rectangle of interest

       Reimplemented in QwtSyntheticPointData.

       Definition at line 124 of file qwt_series_data.h.

   template<typename T > virtual size_t QwtSeriesData< T >::size () const
       [pure virtual]
       Returns
           Number of samples

       Implemented in QwtArraySeriesData< T >, QwtArraySeriesData<
       QwtIntervalSample >, QwtArraySeriesData< QwtVectorFieldSample >,
       QwtArraySeriesData< QwtOHLCSample >, QwtArraySeriesData< QPointF >,
       QwtArraySeriesData< QwtSetSample >, QwtArraySeriesData< QwtPoint3D >,
       QwtSyntheticPointData, QwtCPointerValueData< T >, QwtValuePointData< T
       >, QwtCPointerData< T >, and QwtPointArrayData< T >.


Author
       Generated automatically by Doxygen for Qwt User's Guide from the source
       code.

Version 6.2.0                   Sun Jul 18 2021          QwtSeriesData< T >(3)