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QwtData(3) Qwt User's Guide QwtData(3)

NAME

QwtData -

SYNOPSIS

#include <qwt_data.h>

Inherited by QwtArrayData, QwtCPointerData, and QwtPolygonFData.

Public Member Functions


QwtData ()
virtual ~QwtData ()
virtual QwtDoubleRect boundingRect () const
virtual QwtData * copy () const =0
virtual size_t size () const =0
virtual double x (size_t i) const =0
virtual double y (size_t i) const =0

Protected Member Functions


QwtData & operator= (const QwtData &)

Detailed Description

QwtData defines an interface to any type of curve data.

Classes, derived from QwtData may:

  • store the data in almost any type of container
  • calculate the data on the fly instead of storing it

Member Function Documentation

QwtDoubleRect QwtData::boundingRect () const [virtual]

Returns the bounding rectangle of the data. If there is no bounding rect, like for empty data the rectangle is invalid: QwtDoubleRect::isValid() == false

Warning:

This is an slow implementation iterating over all points. It is intended to be overloaded by derived classes. In case of auto scaling boundingRect() is called for every replot, so it might be worth to implement a cache, or use x(0), x(size() - 1) for ordered data ...

Reimplemented in QwtCPointerData, and QwtArrayData.

virtual QwtData* QwtData::copy () const [pure virtual]

Returns:
Pointer to a copy (virtual copy constructor)

Implemented in QwtCPointerData, QwtArrayData, and QwtPolygonFData.

QwtData& QwtData::operator= (const QwtData &) [protected]

Assignment operator (virtualized)

virtual size_t QwtData::size () const [pure virtual]

Returns:
Size of the data set

Implemented in QwtCPointerData, QwtArrayData, and QwtPolygonFData.

virtual double QwtData::x (size_ti) const [pure virtual]

Return the x value of data point i

Parameters:

i Index

Returns:

x X value of data point i

Implemented in QwtCPointerData, QwtArrayData, and QwtPolygonFData.

virtual double QwtData::y (size_ti) const [pure virtual]

Return the y value of data point i

Parameters:

i Index

Returns:

y Y value of data point i

Implemented in QwtCPointerData, QwtArrayData, and QwtPolygonFData.

Author

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Tue Nov 20 2012 Version 5.2.3