QwtSyntheticPointData(3) Qwt User's Guide QwtSyntheticPointData(3) NAME QwtSyntheticPointData - Synthetic point data. SYNOPSIS #include Inherits QwtPointSeriesData. Public Member Functions QwtSyntheticPointData (size_t size, const QwtInterval &=QwtInterval()) void setSize (size_t size) virtual size_t size () const override void setInterval (const QwtInterval &) QwtInterval interval () const virtual QRectF boundingRect () const override Calculate the bounding rectangle. virtual QPointF sample (size_t index) const override virtual double y (double x) const =0 virtual double x (uint index) const virtual void setRectOfInterest (const QRectF &) override QRectF rectOfInterest () const Additional Inherited Members 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 #include #include #include #include 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( QwtAxis::XBottom, 0.0, 10.0 ); plot.setAxisScale( QwtAxis::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 157 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 20 of file qwt_point_data.cpp. Member Function Documentation QRectF QwtSyntheticPointData::boundingRect () const [override], [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 Reimplemented from QwtPointSeriesData. Definition at line 105 of file qwt_point_data.cpp. QwtInterval QwtSyntheticPointData::interval () const Returns Bounding interval See also setInterval(), size() Definition at line 62 of file qwt_point_data.cpp. QRectF QwtSyntheticPointData::rectOfInterest () const Returns See also setRectOfInterest() Definition at line 89 of file qwt_point_data.cpp. QPointF QwtSyntheticPointData::sample (size_t index) const [override], [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. Reimplemented from QwtArraySeriesData< QPointF >. Definition at line 125 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 53 of file qwt_point_data.cpp. void QwtSyntheticPointData::setRectOfInterest (const QRectF & rect) [override], [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 78 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 33 of file qwt_point_data.cpp. size_t QwtSyntheticPointData::size () const [override], [virtual] Returns Number of points See also setSize(), interval() Reimplemented from QwtArraySeriesData< QPointF >. Definition at line 42 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 148 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 Author Generated automatically by Doxygen for Qwt User's Guide from the source code. Version 6.2.0 Sun Jul 18 2021 QwtSyntheticPointData(3)