QwtPlotVectorField(3)          Qwt User's Guide          QwtPlotVectorField(3)

NAME
       QwtPlotVectorField - A plot item, that represents a vector field.


SYNOPSIS
       #include <qwt_plot_vectorfield.h>

       Inherits QwtPlotSeriesItem, and QwtSeriesStore< QwtVectorFieldSample >.

   Public Types
       enum IndicatorOrigin { OriginHead, OriginTail, OriginCenter }
       enum PaintAttribute { FilterVectors = 0x01 }
       enum MagnitudeMode { MagnitudeAsColor = 0x01, MagnitudeAsLength = 0x02
           }
       typedef QFlags< PaintAttribute > PaintAttributes
       typedef QFlags< MagnitudeMode > MagnitudeModes

   Public Member Functions
       QwtPlotVectorField (const QString &title=QString())
       QwtPlotVectorField (const QwtText &title)
       virtual ~QwtPlotVectorField ()
           Destructor.
       void setPaintAttribute (PaintAttribute, bool on=true)
       bool testPaintAttribute (PaintAttribute) const
       void setMagnitudeMode (MagnitudeMode, bool on=true)
       bool testMagnitudeMode (MagnitudeMode) const
       void setSymbol (QwtVectorFieldSymbol *)
       const QwtVectorFieldSymbol * symbol () const
       void setPen (const QPen &)
       QPen pen () const
       void setBrush (const QBrush &)
           Assign a brush.
       QBrush brush () const
       void setRasterSize (const QSizeF &)
       QSizeF rasterSize () const
       void setIndicatorOrigin (IndicatorOrigin)
       IndicatorOrigin indicatorOrigin () const
       void setSamples (const QVector< QwtVectorFieldSample > &)
       void setSamples (QwtVectorFieldData *)
       void setColorMap (QwtColorMap *)
       const QwtColorMap * colorMap () const
       void setMagnitudeRange (const QwtInterval &)
       QwtInterval magnitudeRange () const
       void setMinArrowLength (double)
       double minArrowLength () const
       void setMaxArrowLength (double)
       double maxArrowLength () const
       virtual double arrowLength (double magnitude) const
       virtual QRectF boundingRect () const override
       virtual void drawSeries (QPainter *, const QwtScaleMap &xMap, const
           QwtScaleMap &yMap, const QRectF &canvasRect, int from, int to)
           const override
       virtual int rtti () const override
       virtual QwtGraphic legendIcon (int index, const QSizeF &) const
           override
       void setMagnitudeScaleFactor (double factor)
           Set the magnitudeScaleFactor.
       double magnitudeScaleFactor () const

   Protected Member Functions
       virtual void drawSymbols (QPainter *, const QwtScaleMap &xMap, const
           QwtScaleMap &yMap, const QRectF &canvasRect, int from, int to)
           const
       virtual void drawSymbol (QPainter *, double x, double y, double vx,
           double vy) const
       virtual void dataChanged () override
           dataChanged() indicates, that the series has been changed.

Detailed Description
       A plot item, that represents a vector field.

       A vector field is a representation of a points with a given magnitude
       and direction as arrows. While the direction affects the direction of
       the arrow, the magnitude might be represented as a color or by the
       length of the arrow.

       See also
           QwtVectorFieldSymbol, QwtVectorFieldSample

       Definition at line 30 of file qwt_plot_vectorfield.h.

Member Typedef Documentation
   typedef QFlags<MagnitudeMode > QwtPlotVectorField::MagnitudeModes
       An ORed combination of MagnitudeMode values.

       Definition at line 90 of file qwt_plot_vectorfield.h.

   typedef QFlags<PaintAttribute > QwtPlotVectorField::PaintAttributes
       An ORed combination of PaintAttribute values.

       Definition at line 67 of file qwt_plot_vectorfield.h.

Member Enumeration Documentation
   enum QwtPlotVectorField::IndicatorOrigin
       Depending on the origin the indicator symbol ( usually an arrow ) will
       be to the position of the corresponding sample.

       Enumerator

       OriginHead
              symbol points to the sample position

       OriginTail
              The arrow starts at the sample position.

       OriginCenter
              The arrow is centered at the sample position.

       Definition at line 39 of file qwt_plot_vectorfield.h.

   enum QwtPlotVectorField::MagnitudeMode
       Depending on the MagnitudeMode the magnitude component will have an
       impact on the attributes of the symbol/arrow.

       See also
           setMagnitudeMode()

       Enumerator

       MagnitudeAsColor
              The magnitude will be mapped to a color using a color map

       See also
           magnitudeRange(), colorMap()

       MagnitudeAsLength
              The magnitude will have an impact on the length of the
              arrow/symbol

       See also
           arrowLength(), magnitudeScaleFactor()

       Definition at line 75 of file qwt_plot_vectorfield.h.

   enum QwtPlotVectorField::PaintAttribute
       Attributes to modify the rendering

       See also
           setPaintAttribute(), testPaintAttribute()

       Definition at line 55 of file qwt_plot_vectorfield.h.

Constructor & Destructor Documentation
   QwtPlotVectorField::QwtPlotVectorField (const QString & title = QString())
       [explicit]
       Constructor

       Parameters
           title Title of the curve

       Definition at line 302 of file qwt_plot_vectorfield.cpp.

   QwtPlotVectorField::QwtPlotVectorField (const QwtText & title) [explicit]
       Constructor

       Parameters
           title Title of the curve

       Definition at line 292 of file qwt_plot_vectorfield.cpp.

Member Function Documentation
   double QwtPlotVectorField::arrowLength (double magnitude) const [virtual]
       Computes length of the arrow in screen coordinate units based on its
       magnitude.

       Default implementation simply scales the vector using the
       magnitudeScaleFactor() If the result is not null, the length is then
       bounded into the interval [ minArrowLength(), maxArrowLength() ].

       Re-implement this function to provide special handling for zero/non-
       zero magnitude arrows, or impose minimum/maximum arrow length limits.

       Parameters
           magnitude Magnitude

       Returns
           Length of arrow to be drawn in dependence of vector magnitude.

       See also
           magnitudeScaleFactor, minArrowLength(), maxArrowLength()

       Note
           Has no effect when QwtPlotVectorField::MagnitudeAsLength is not
           enabled

       Definition at line 726 of file qwt_plot_vectorfield.cpp.

   QRectF QwtPlotVectorField::boundingRect () const [override],  [virtual]
       Returns
           An invalid bounding rect: QRectF(1.0, 1.0, -2.0, -2.0)

       Note
           A width or height < 0.0 is ignored by the autoscaler

       Reimplemented from QwtPlotSeriesItem.

       Definition at line 749 of file qwt_plot_vectorfield.cpp.

   QBrush QwtPlotVectorField::brush () const
       Returns
           Brush used to fill the symbol

       See also
           setBrush(), pen()

       Definition at line 379 of file qwt_plot_vectorfield.cpp.

   const QwtColorMap * QwtPlotVectorField::colorMap () const
       Returns
           Color Map used for mapping the intensity values to colors

       See also
           setColorMap()

       Definition at line 590 of file qwt_plot_vectorfield.cpp.

   void QwtPlotVectorField::drawSeries (QPainter * painter, const QwtScaleMap
       & xMap, const QwtScaleMap & yMap, const QRectF & canvasRect, int from,
       int to) const [override],  [virtual]
       Draw a subset of the points

       Parameters
           painter Painter
           xMap Maps x-values into pixel coordinates.
           yMap Maps y-values into pixel coordinates.
           canvasRect Contents rectangle of the canvas
           from Index of the first sample to be painted
           to Index of the last sample to be painted. If to < 0 the series
           will be painted to its last sample.

       Implements QwtPlotSeriesItem.

       Definition at line 807 of file qwt_plot_vectorfield.cpp.

   void QwtPlotVectorField::drawSymbol (QPainter * painter, double x, double
       y, double vx, double vy) const [protected],  [virtual]
       Draw a arrow/symbols at a specific position

       x, y, are paint device coordinates, while vx, vy are from the
       corresponding sample.

       See also
           setSymbol(), drawSeries()

       Definition at line 975 of file qwt_plot_vectorfield.cpp.

   void QwtPlotVectorField::drawSymbols (QPainter * painter, const QwtScaleMap
       & xMap, const QwtScaleMap & yMap, const QRectF & canvasRect, int from,
       int to) const [protected],  [virtual]
       Draw symbols

       Parameters
           painter Painter
           xMap x map
           yMap y map
           canvasRect Contents rectangle of the canvas
           from Index of the first sample to be painted
           to Index of the last sample to be painted

       See also
           setSymbol(), drawSymbol(), drawSeries()

       Definition at line 847 of file qwt_plot_vectorfield.cpp.

   QwtPlotVectorField::IndicatorOrigin QwtPlotVectorField::indicatorOrigin ()
       const
       Returns
           origin for the symbols/arrows

       Definition at line 401 of file qwt_plot_vectorfield.cpp.

   QwtGraphic QwtPlotVectorField::legendIcon (int index, const QSizeF & size)
       const [override],  [virtual]
       Returns
           Icon representing the vector fields on the legend

       Parameters
           index Index of the legend entry ( ignored as there is only one )
           size Icon size

       See also
           QwtPlotItem::setLegendIconSize(), QwtPlotItem::legendData()

       Reimplemented from QwtPlotItem.

       Definition at line 770 of file qwt_plot_vectorfield.cpp.

   QwtInterval QwtPlotVectorField::magnitudeRange () const
       Returns
           min/max magnitudes to be used for color map lookups

       See also
           setMagnitudeRange(), colorMap()

       Definition at line 645 of file qwt_plot_vectorfield.cpp.

   double QwtPlotVectorField::magnitudeScaleFactor () const
       Returns
           Scale factor used to calculate the arrow length from the magnitude

       The length of the arrow in screen coordinate units is calculated by
       scaling the magnitude by the magnitudeScaleFactor.

       Default implementation simply scales the vector using the
       magnitudeScaleFactor property. Re-implement this function to provide
       special handling for zero/non-zero magnitude arrows, or impose
       minimum/maximum arrow length limits.

       Returns
           Length of arrow to be drawn in dependence of vector magnitude.

       See also
           magnitudeScaleFactor

       Note
           Has no effect when QwtPlotVectorField::MagnitudeAsLength is not
           enabled

       Definition at line 440 of file qwt_plot_vectorfield.cpp.

   double QwtPlotVectorField::maxArrowLength () const
       Returns
           maximum for the arrow length

       See also
           setMinArrowLength(), maxArrowLength(), arrowLength()

       Note
           Has no effect when QwtPlotVectorField::MagnitudeAsLength is not
           enabled

       Definition at line 705 of file qwt_plot_vectorfield.cpp.

   double QwtPlotVectorField::minArrowLength () const
       Returns
           minimum for the arrow length of non zero vectors

       See also
           setMinArrowLength(), maxArrowLength(), arrowLength()

       Note
           Has no effect when QwtPlotVectorField::MagnitudeAsLength is not
           enabled

       Definition at line 675 of file qwt_plot_vectorfield.cpp.

   QPen QwtPlotVectorField::pen () const
       Returns
           Pen used to draw the lines

       See also
           setPen(), brush()

       Definition at line 351 of file qwt_plot_vectorfield.cpp.

   QSizeF QwtPlotVectorField::rasterSize () const
       Returns
           raster size used for filtering samples

       See also
           setRasterSize(), QwtPlotVectorField::FilterVectors

       Definition at line 463 of file qwt_plot_vectorfield.cpp.

   int QwtPlotVectorField::rtti () const [override],  [virtual]
       Returns
           QwtPlotItem::Rtti_PlotField

       Reimplemented from QwtPlotItem.

       Definition at line 503 of file qwt_plot_vectorfield.cpp.

   void QwtPlotVectorField::setBrush (const QBrush & brush)
       Assign a brush.

       Parameters
           brush New brush

       See also
           brush(), pen()

       Note
           the brush is ignored in MagnitudeAsColor mode

       Definition at line 364 of file qwt_plot_vectorfield.cpp.

   void QwtPlotVectorField::setColorMap (QwtColorMap * colorMap)
       Change the color map

       The color map is used to map the magnitude of a sample into a color
       using a known range for the magnitudes.

       Parameters
           colorMap Color Map

       See also
           colorMap(), magnitudeRange()

       Definition at line 571 of file qwt_plot_vectorfield.cpp.

   void QwtPlotVectorField::setIndicatorOrigin (IndicatorOrigin origin)
       Set the origin for the symbols/arrows

       Parameters
           origin Origin

       See also
           indicatorOrigin()

       Definition at line 390 of file qwt_plot_vectorfield.cpp.

   void QwtPlotVectorField::setMagnitudeMode (MagnitudeMode mode, bool on =
       true)
       Specify a mode how to represent the magnitude a n arrow/symbol

       Parameters
           mode Mode
           on On/Off

       See also
           testMagnitudeMode()

       Definition at line 602 of file qwt_plot_vectorfield.cpp.

   void QwtPlotVectorField::setMagnitudeRange (const QwtInterval &
       magnitudeRange)
       Sets the min/max magnitudes to be used for color map lookups.

       If invalid (min=max=0 or negative values), the range is determined from
       the current range of magnitudes in the vector samples.

       See also
           magnitudeRange(), colorMap()

       Definition at line 632 of file qwt_plot_vectorfield.cpp.

   void QwtPlotVectorField::setMagnitudeScaleFactor (double factor)
       Set the magnitudeScaleFactor. The length of the arrow in screen
       coordinate units is calculated by scaling the magnitude by the
       magnitudeScaleFactor.

       Parameters
           factor Scale factor

       See also
           magnitudeScaleFactor(), arrowLength()

       Note
           Has no effect when QwtPlotVectorField::MagnitudeAsLength is not
           enabled

       Definition at line 417 of file qwt_plot_vectorfield.cpp.

   void QwtPlotVectorField::setMaxArrowLength (double length)
       Set a maximum for the arrow length

       Parameters
           length Maximum for the arrow length in pixels

       See also
           maxArrowLength(), setMinArrowLength(), arrowLength()

       Note
           Has no effect when QwtPlotVectorField::MagnitudeAsLength is not
           enabled

       Definition at line 688 of file qwt_plot_vectorfield.cpp.

   void QwtPlotVectorField::setMinArrowLength (double length)
       Set a minimum for the arrow length of non zero vectors

       Parameters
           length Minimum for the arrow length in pixels

       See also
           minArrowLength(), setMaxArrowLength(), arrowLength()

       Note
           Has no effect when QwtPlotVectorField::MagnitudeAsLength is not
           enabled

       Definition at line 658 of file qwt_plot_vectorfield.cpp.

   void QwtPlotVectorField::setPaintAttribute (PaintAttribute attribute, bool
       on = true)
       Specify an attribute how to draw the curve

       Parameters
           attribute Paint attribute
           on On/Off

       See also
           testPaintAttribute()

       Definition at line 475 of file qwt_plot_vectorfield.cpp.

   void QwtPlotVectorField::setPen (const QPen & pen)
       Assign a pen

       Parameters
           pen New pen

       See also
           pen(), brush()

       Note
           the pen is ignored in MagnitudeAsColor mode

       Definition at line 336 of file qwt_plot_vectorfield.cpp.

   void QwtPlotVectorField::setRasterSize (const QSizeF & size)
       Set the raster size used for filtering samples

       See also
           rasterSize(), QwtPlotVectorField::FilterVectors

       Definition at line 450 of file qwt_plot_vectorfield.cpp.

   void QwtPlotVectorField::setSamples (const QVector< QwtVectorFieldSample >
       & samples)
       Initialize data with an array of samples.

       Parameters
           samples Vector of points

       Definition at line 541 of file qwt_plot_vectorfield.cpp.

   void QwtPlotVectorField::setSamples (QwtVectorFieldData * data)
       Assign a series of samples

       setSamples() is just a wrapper for setData() without any additional
       value - beside that it is easier to find for the developer.

       Parameters
           data Data

       Warning
           The item takes ownership of the data object, deleting it when its
           not used anymore.

       Definition at line 556 of file qwt_plot_vectorfield.cpp.

   void QwtPlotVectorField::setSymbol (QwtVectorFieldSymbol * symbol)
       Sets a new arrow symbol (implementation of arrow drawing code).

       Parameters
           symbol Arrow symbol

       See also
           symbol(), drawSymbol()

       Note
           Ownership is transferred to QwtPlotVectorField.

       Definition at line 516 of file qwt_plot_vectorfield.cpp.

   const QwtVectorFieldSymbol * QwtPlotVectorField::symbol () const
       Returns
           arrow symbol

       See also
           setSymbol(), drawSymbol()

       Definition at line 532 of file qwt_plot_vectorfield.cpp.

   bool QwtPlotVectorField::testMagnitudeMode (MagnitudeMode mode) const
       Returns
           True, when mode is enabled

       See also
           MagnitudeMode, setMagnitudeMode()

       Definition at line 619 of file qwt_plot_vectorfield.cpp.

   bool QwtPlotVectorField::testPaintAttribute (PaintAttribute attribute)
       const
       Returns
           True, when attribute is enabled

       See also
           PaintAttribute, setPaintAttribute()

       Definition at line 496 of file qwt_plot_vectorfield.cpp.


Author
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Version 6.2.0                   Sun Jul 18 2021          QwtPlotVectorField(3)