NAME¶

QwtSyntheticPointData - Synthetic point data.

SYNOPSIS¶

#include <qwt_series_data.h> Inherits QwtSeriesData< QPointF >.

Public Member Functions¶

QwtSyntheticPointData (size_t size, const QwtInterval &=QwtInterval()) void setSize (size_t size) size_t size () const void setInterval (const QwtInterval &) QwtInterval interval () const virtual QRectF boundingRect () const virtual QPointF sample (size_t i) const virtual double y (double x) const =0 virtual double x (uint index) const virtual void setRectOfInterest (const QRectF &) QRectF rectOfInterest () const

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 'rect 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(SinusData());
    curve->attach(&plot);

    plot.show();
    return a.exec();
}
   .fi

Constructor & Destructor Documentation¶

QwtSyntheticPointData::QwtSyntheticPointData (size_tsize, const QwtInterval &interval = QwtInterval()) Constructor¶

Parameters: See also:

Member Function Documentation¶

QRectF QwtSyntheticPointData::boundingRect () const [virtual]¶

Calculate the bounding rect. 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: Implements QwtSeriesData< QPointF >.

QwtInterval QwtSyntheticPointData::interval () const Returns:¶

See also:

QRectF QwtSyntheticPointData::rectOfInterest () const Returns:¶

See also:

QPointF QwtSyntheticPointData::sample (size_tindex) const [virtual] Calculate the point from an index¶

Parameters: Returns: Warning: Implements QwtSeriesData< QPointF >.

void QwtSyntheticPointData::setInterval (const QwtInterval &interval) Set the bounding interval¶

Parameters: See also:

void QwtSyntheticPointData::setRectOfInterest (const QRectF &rect) [virtual] Set a the 'rect 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: Reimplemented from QwtSeriesData< QPointF >.

void QwtSyntheticPointData::setSize (size_tsize) Change the number of points¶

Parameters: See also:

size_t QwtSyntheticPointData::size () const [virtual] Returns:¶

See also: Implements QwtSeriesData< QPointF >.

double QwtSyntheticPointData::x (uintindex) const [virtual] Calculate a x-value from an index¶

x values are calculated by deviding an interval into equidistant steps. If !interval().isValid() the interval is calculated from the 'rect of interest'. See also:

virtual double QwtSyntheticPointData::y (doublex) const [pure virtual] Calculate a y value for a x value¶

Parameters: Returns:

Author¶

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