QwtSeriesData - (unknown subject)

NAME

QwtSeriesData< T > − Abstract interface for iterating over samples.

SYNOPSIS

#include <qwt_series_data.h>

Inherited by QwtArraySeriesData< T >.

Public Member Functions

QwtSeriesData ()
Constructor.
virtual ˜QwtSeriesData ()
Destructor.
virtual size_t size () const =0
virtual T sample (size_t i) const =0
T firstSample () const
T lastSample () const
virtual QRectF boundingRect () const
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:

•

size()

Should return number of data points.

•

sample()

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

•

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.

Constructor & Destructor Documentation

template<typename T> QwtSeriesData< T >::QwtSeriesData ()

Constructor.

Definition at line 130 of file qwt_series_data.h.

template<typename T> QwtSeriesData< T >::˜QwtSeriesData () [virtual]

Destructor.

Definition at line 136 of file qwt_series_data.h.

Member Function Documentation

template<typename T> virtual QRectF QwtSeriesData< T >::boundingRect ()const [inline], [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.

Returns

Bounding rectangle

Reimplemented in QwtSyntheticPointData.

Definition at line 100 of file qwt_series_data.h.

template<typename T> T QwtSeriesData< T >::firstSample () const [inline]

Returns the first sample in the list.

Warning

This function assumes that the list isn’t empty.

Definition at line 80 of file qwt_series_data.h.

template<typename T> T QwtSeriesData< T >::lastSample () const [inline]

Returns the first sample in the list.

Warning

This function assumes that the list isn’t empty.

Definition at line 86 of file qwt_series_data.h.

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

template<typename T> void QwtSeriesData< T >::setRectOfInterest (constQRectF & 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 141 of file qwt_series_data.h.

template<typename T> virtual size_t QwtSeriesData< T >::size () const [purevirtual]

Returns

Number of samples

Member Data Documentation

template<typename T> QRectF QwtSeriesData< T >::cachedBoundingRect[mutable], [protected]

Can be used to cache a calculated bounding rectangle.

Definition at line 123 of file qwt_series_data.h.

Author

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Updated 2026-06-01 - jenkler.se | uex.se