.TH "QwtSyntheticPointData" 3 "Wed Jan 2 2019" "Version 6.1.4" "Qwt User's Guide" \" -*- nroff -*-
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.SH NAME
QwtSyntheticPointData \- Synthetic point data\&.  

.SH SYNOPSIS
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.PP
.PP
\fC#include <qwt_point_data\&.h>\fP
.PP
Inherits \fBQwtSeriesData< QPointF >\fP\&.
.SS "Public Member Functions"

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.ti -1c
.RI "\fBQwtSyntheticPointData\fP (size_t \fBsize\fP, const \fBQwtInterval\fP &=\fBQwtInterval\fP())"
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.RI "void \fBsetSize\fP (size_t \fBsize\fP)"
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.RI "virtual size_t \fBsize\fP () const"
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.RI "void \fBsetInterval\fP (const \fBQwtInterval\fP &)"
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.RI "\fBQwtInterval\fP \fBinterval\fP () const"
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.RI "virtual QRectF \fBboundingRect\fP () const"
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.RI "Calculate the bounding rectangle\&. "
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.RI "virtual QPointF \fBsample\fP (size_t index) const"
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.RI "virtual double \fBy\fP (double \fBx\fP) const =0"
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.RI "virtual double \fBx\fP (uint index) const"
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.RI "virtual void \fBsetRectOfInterest\fP (const QRectF &)"
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.RI "QRectF \fBrectOfInterest\fP () const"
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.SS "Additional Inherited Members"
.SH "Detailed Description"
.PP 
Synthetic point data\&. 

\fBQwtSyntheticPointData\fP provides a fixed number of points for an interval\&. The points are calculated in equidistant steps in x-direction\&.
.PP
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\&.
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\fBExample\fP
.RS 4

.RE
.PP
The following example shows how to implement a sinus curve\&.
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.PP
.nf
#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();
}
.fi
.PP
 
.SH "Constructor & Destructor Documentation"
.PP 
.SS "QwtSyntheticPointData::QwtSyntheticPointData (size_t size, const \fBQwtInterval\fP & interval = \fC\fBQwtInterval\fP()\fP)"
Constructor
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\fBParameters:\fP
.RS 4
\fIsize\fP Number of points 
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\fIinterval\fP Bounding interval for the points
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\fBSee also:\fP
.RS 4
\fBsetInterval()\fP, \fBsetSize()\fP 
.RE
.PP

.SH "Member Function Documentation"
.PP 
.SS "QRectF QwtSyntheticPointData::boundingRect () const\fC [virtual]\fP"

.PP
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 )\&.
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\fBReturns:\fP
.RS 4
Bounding rectangle 
.RE
.PP

.PP
Implements \fBQwtSeriesData< QPointF >\fP\&.
.SS "\fBQwtInterval\fP QwtSyntheticPointData::interval () const"

.PP
\fBReturns:\fP
.RS 4
Bounding interval 
.RE
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\fBSee also:\fP
.RS 4
\fBsetInterval()\fP, \fBsize()\fP 
.RE
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.SS "QRectF QwtSyntheticPointData::rectOfInterest () const"

.PP
\fBReturns:\fP
.RS 4
'rectangle of interest' 
.RE
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\fBSee also:\fP
.RS 4
\fBsetRectOfInterest()\fP 
.RE
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.SS "QPointF QwtSyntheticPointData::sample (size_t index) const\fC [virtual]\fP"
Calculate the point from an index
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\fBParameters:\fP
.RS 4
\fIindex\fP Index 
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\fBReturns:\fP
.RS 4
QPointF(x(index), y(x(index)));
.RE
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\fBWarning:\fP
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For invalid indices ( index < 0 || index >= \fBsize()\fP ) (0, 0) is returned\&. 
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.PP

.PP
Implements \fBQwtSeriesData< QPointF >\fP\&.
.SS "void QwtSyntheticPointData::setInterval (const \fBQwtInterval\fP & interval)"
Set the bounding interval
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\fBParameters:\fP
.RS 4
\fIinterval\fP Interval 
.RE
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\fBSee also:\fP
.RS 4
\fBinterval()\fP, \fBsetSize()\fP 
.RE
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.SS "void QwtSyntheticPointData::setRectOfInterest (const QRectF & rect)\fC [virtual]\fP"
Set a the 'rectangle of interest'
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\fBQwtPlotSeriesItem\fP defines the current area of the plot canvas as 'rect of interest' ( \fBQwtPlotSeriesItem::updateScaleDiv()\fP )\&.
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If \fBinterval()\fP\&.isValid() == false the x values are calculated in the interval rect\&.left() -> rect\&.right()\&.
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\fBSee also:\fP
.RS 4
\fBrectOfInterest()\fP 
.RE
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.PP
Reimplemented from \fBQwtSeriesData< QPointF >\fP\&.
.SS "void QwtSyntheticPointData::setSize (size_t size)"
Change the number of points
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\fBParameters:\fP
.RS 4
\fIsize\fP Number of points 
.RE
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\fBSee also:\fP
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\fBsize()\fP, \fBsetInterval()\fP 
.RE
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.SS "size_t QwtSyntheticPointData::size () const\fC [virtual]\fP"

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\fBReturns:\fP
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Number of points 
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\fBSee also:\fP
.RS 4
\fBsetSize()\fP, \fBinterval()\fP 
.RE
.PP

.PP
Implements \fBQwtSeriesData< QPointF >\fP\&.
.SS "double QwtSyntheticPointData::x (uint index) const\fC [virtual]\fP"
Calculate a x-value from an index
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x values are calculated by dividing an interval into equidistant steps\&. If !interval()\&.isValid() the interval is calculated from the 'rectangle of interest'\&.
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\fBParameters:\fP
.RS 4
\fIindex\fP Index of the requested point 
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\fBReturns:\fP
.RS 4
Calculated x coordinate
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\fBSee also:\fP
.RS 4
\fBinterval()\fP, \fBrectOfInterest()\fP, \fBy()\fP 
.RE
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.SS "virtual double QwtSyntheticPointData::y (double x) const\fC [pure virtual]\fP"
Calculate a y value for a x value
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\fBParameters:\fP
.RS 4
\fIx\fP x value 
.RE
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\fBReturns:\fP
.RS 4
Corresponding y value 
.RE
.PP


.SH "Author"
.PP 
Generated automatically by Doxygen for Qwt User's Guide from the source code\&.