Synthetic point data. More...

#include <qwt_point_data.h>

Inheritance diagram for QwtSyntheticPointData:

Public Member Functions
virtual QRectF	boundingRect () const
	Calculate the bounding rectangle. More...

QwtInterval	interval () const

	QwtSyntheticPointData (size_t size, const QwtInterval &=QwtInterval())

QRectF	rectOfInterest () const

virtual QPointF	sample (size_t i) const

void	setInterval (const QwtInterval &)

virtual void	setRectOfInterest (const QRectF &)

void	setSize (size_t size)

virtual size_t	size () const

virtual double	x (uint index) const

virtual double	y (double x) const =0

Public Member Functions inherited from QwtSeriesData< QPointF >
	QwtSeriesData ()
	Constructor. More...

virtual	~QwtSeriesData ()
	Destructor. More...

Private Attributes
QwtInterval	d_interval

QwtInterval	d_intervalOfInterest

QRectF	d_rectOfInterest

size_t	d_size

Additional Inherited Members
Protected Attributes inherited from QwtSeriesData< QPointF >
QRectF	d_boundingRect
	Can be used to cache a calculated bounding rectangle. More...

Detailed Description

Synthetic point data.

QwtSyntheticPointData provides a fixed number of points for an interval. The points are calculated in equidistant steps in x-direction.

If the interval is invalid, the points are calculated for the "rectangle of interest", what normally is the displayed area on the plot canvas. In this mode you get different levels of detail, when zooming in/out.

Example

The following example shows how to implement a sinus curve.

#include <cmath>
#include <qwt_series_data.h>
#include <qwt_plot_curve.h>
#include <qwt_plot.h>
#include <qapplication.h>
class SinusData: public QwtSyntheticPointData
{
public:
    SinusData():
        QwtSyntheticPointData( 100 )
    {
    }
    virtual double y( double x ) const
    {
        return qSin( x );
    }
};
int main(int argc, char **argv)
{
    QApplication a( argc, argv );
    QwtPlot plot;
    plot.setAxisScale( QwtPlot::xBottom, 0.0, 10.0 );
    plot.setAxisScale( QwtPlot::yLeft, -1.0, 1.0 );
    QwtPlotCurve *curve = new QwtPlotCurve( "y = sin(x)" );
    curve->setData( new SinusData() );
    curve->attach( &plot );
    plot.show();
    return a.exec();
}

Definition at line 112 of file qwt_point_data.h.

Constructor & Destructor Documentation

QwtSyntheticPointData::QwtSyntheticPointData	(	size_t	size,
		const QwtInterval &	interval = `QwtInterval()`
	)

Constructor

Parameters

size	Number of points
interval	Bounding interval for the points

See also: setInterval(), setSize()

Definition at line 166 of file qwt_point_data.cpp.

Member Function Documentation

QRectF QwtSyntheticPointData::boundingRect ( ) const

virtual

Calculate the bounding rectangle.

This implementation iterates over all points, what could often be implemented much faster using the characteristics of the series. When there are many points it is recommended to overload and reimplement this method using the characteristics of the series ( if possible ).

Returns: Bounding rectangle

Implements QwtSeriesData< QPointF >.

Definition at line 251 of file qwt_point_data.cpp.

QwtInterval QwtSyntheticPointData::interval ( ) const

Returns: Bounding interval

See also: setInterval(), size()

Definition at line 208 of file qwt_point_data.cpp.

QRectF QwtSyntheticPointData::rectOfInterest ( ) const

Returns: "rectangle of interest"

See also: setRectOfInterest()

Definition at line 235 of file qwt_point_data.cpp.

QPointF QwtSyntheticPointData::sample ( size_t index ) const

virtual

Calculate the point from an index

Parameters

index Index

Returns: QPointF(x(index), y(x(index)));

Warning: For invalid indices ( index < 0 || index >= size() ) (0, 0) is returned.

Implements QwtSeriesData< QPointF >.

Definition at line 271 of file qwt_point_data.cpp.

void QwtSyntheticPointData::setInterval ( const QwtInterval & interval )

Set the bounding interval

Parameters

interval Interval

See also: interval(), setSize()

Definition at line 199 of file qwt_point_data.cpp.

void QwtSyntheticPointData::setRectOfInterest ( const QRectF & rect )

virtual

Set a the "rectangle of interest"

QwtPlotSeriesItem defines the current area of the plot canvas as "rect of interest" ( QwtPlotSeriesItem::updateScaleDiv() ).

If interval().isValid() == false the x values are calculated in the interval rect.left() -> rect.right().

See also: rectOfInterest()

Reimplemented from QwtSeriesData< QPointF >.

Definition at line 224 of file qwt_point_data.cpp.

void QwtSyntheticPointData::setSize ( size_t size )

Change the number of points

Parameters

size	Number of points

See also: size(), setInterval()

Definition at line 179 of file qwt_point_data.cpp.

size_t QwtSyntheticPointData::size ( ) const

virtual

Returns: Number of points

See also: setSize(), interval()

Implements QwtSeriesData< QPointF >.

Definition at line 188 of file qwt_point_data.cpp.

double QwtSyntheticPointData::x ( uint index ) const

virtual

Calculate a x-value from an index

x values are calculated by dividing an interval into equidistant steps. If !interval().isValid() the interval is calculated from the "rectangle of interest".

Parameters

index Index of the requested point

Returns: Calculated x coordinate

See also: interval(), rectOfInterest(), y()

Definition at line 294 of file qwt_point_data.cpp.

virtual double QwtSyntheticPointData::y ( double x ) const

pure virtual

Calculate a y value for a x value

Parameters

x x value

Returns: Corresponding y value

Member Data Documentation

QwtInterval QwtSyntheticPointData::d_interval

private

Definition at line 141 of file qwt_point_data.h.

QwtInterval QwtSyntheticPointData::d_intervalOfInterest

private

Definition at line 143 of file qwt_point_data.h.

QRectF QwtSyntheticPointData::d_rectOfInterest

private

Definition at line 142 of file qwt_point_data.h.

size_t QwtSyntheticPointData::d_size

private

Definition at line 140 of file qwt_point_data.h.

The documentation for this class was generated from the following files:

Public Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation