QwtData

Section: Qwt User's Guide (3) Updated: 16 Nov 2004 Local index Up

NAME

QwtData -

SYNOPSIS

Inherited by QwtArrayData, QwtCPointerData, and QwtDoublePointData.

Detailed Description

QwtData defines an interface to any type of 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
•: implement data with error bars (this implies subclassing QwtPlot, QwtCurve and QwtPlotCurve)

Warning:

: In the future, 'almost any type of container' may be limited to containers supporting bi-directional iterators like the vector, array and list classes in Qt or in the standard template library.

Definition at line 40 of file qwt_data.h.

Public Member Functions

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

virtual QwtDoubleRect boundingRect () const

Protected Member Functions

QwtData & operator= (const QwtData &)

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 QwtArrayData, and QwtCPointerData.

Definition at line 33 of file qwt_data.cpp.

References size(), x(), and y().

Referenced by QwtCurve::boundingRect().