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

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 Types inherited from QwtPlotItem

enum RttiValues { Rtti_PlotItem = 0, Rtti_PlotGrid, Rtti_PlotScale, Rtti_PlotLegend, Rtti_PlotMarker, Rtti_PlotCurve, Rtti_PlotSpectroCurve, Rtti_PlotIntervalCurve, Rtti_PlotHistogram, Rtti_PlotSpectrogram, Rtti_PlotGraphic, Rtti_PlotTradingCurve, Rtti_PlotBarChart, Rtti_PlotMultiBarChart, Rtti_PlotShape, Rtti_PlotTextLabel, Rtti_PlotZone, Rtti_PlotVectorField, Rtti_PlotUserItem = 1000 }
Runtime type information.
enum ItemAttribute { Legend = 0x01, AutoScale = 0x02, Margins = 0x04 }
Plot Item Attributes.
enum ItemInterest { ScaleInterest = 0x01, LegendInterest = 0x02 }
Plot Item Interests.
enum RenderHint { RenderAntialiased = 0x1 }
Render hints.
typedef QFlags< ItemAttribute > ItemAttributes
typedef QFlags< ItemInterest > ItemInterests
typedef QFlags< RenderHint > RenderHints

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

Public Member Functions inherited from QwtPlotSeriesItem

QwtPlotSeriesItem (const QString &title=QString())
QwtPlotSeriesItem (const QwtText &title)
virtual ˜QwtPlotSeriesItem ()
Destructor.
void setOrientation (Qt::Orientation)
Qt::Orientation orientation () const
virtual void draw (QPainter *, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect) const override
Draw the complete series.
virtual void updateScaleDiv (const QwtScaleDiv &, const QwtScaleDiv &) override
Update the item to changes of the axes scale division.

Public Member Functions inherited from QwtPlotItem

QwtPlotItem ()
QwtPlotItem (const QString &title)
QwtPlotItem (const QwtText &title)
virtual ˜QwtPlotItem ()
Destroy the QwtPlotItem.
void attach (QwtPlot *plot)
Attach the item to a plot.
void detach ()
This method detaches a QwtPlotItem from any QwtPlot it has been associated with.
QwtPlot * plot () const
Return attached plot.
void setTitle (const QString &title)
void setTitle (const QwtText &title)
const QwtText & title () const
void setItemAttribute (ItemAttribute, bool on=true)
bool testItemAttribute (ItemAttribute) const
void setItemInterest (ItemInterest, bool on=true)
bool testItemInterest (ItemInterest) const
void setRenderHint (RenderHint, bool on=true)
bool testRenderHint (RenderHint) const
void setRenderThreadCount (uint numThreads)
uint renderThreadCount () const
void setLegendIconSize (const QSize &)
QSize legendIconSize () const
double z () const
void setZ (double z)
Set the z value.
void show ()
Show the item.
void hide ()
Hide the item.
virtual void setVisible (bool)
bool isVisible () const
void setAxes (QwtAxisId xAxis, QwtAxisId yAxis)
void setXAxis (QwtAxisId)
QwtAxisId xAxis () const
Return xAxis.
void setYAxis (QwtAxisId)
QwtAxisId yAxis () const
Return yAxis.
virtual void itemChanged ()
virtual void legendChanged ()
virtual void getCanvasMarginHint (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect, double &left, double &top, double &right, double &bottom) const
Calculate a hint for the canvas margin.
virtual void updateLegend (const QwtPlotItem *, const QList< QwtLegendData > &)
Update the item to changes of the legend info.
QRectF scaleRect (const QwtScaleMap &, const QwtScaleMap &) const
Calculate the bounding scale rectangle of 2 maps.
QRectF paintRect (const QwtScaleMap &, const QwtScaleMap &) const
Calculate the bounding paint rectangle of 2 maps.
virtual QList< QwtLegendData > legendData () const
Return all information, that is needed to represent the item on the legend.

Public Member Functions inherited from QwtAbstractSeriesStore

virtual ˜QwtAbstractSeriesStore ()
Destructor.

Public Member Functions inherited from QwtSeriesStore< QwtVectorFieldSample >

QwtSeriesStore ()
Constructor The store contains no series.
˜QwtSeriesStore ()
Destructor.
void setData (QwtSeriesData< QwtVectorFieldSample > *series)
QwtSeriesData< QwtVectorFieldSample > * data ()
const QwtSeriesData< QwtVectorFieldSample > * data () const
QwtVectorFieldSample sample (int index) const
virtual size_t dataSize () const override
virtual QRectF dataRect () const override
virtual void setRectOfInterest (const QRectF &rect) override
QwtSeriesData< QwtVectorFieldSample > * swapData (QwtSeriesData< QwtVectorFieldSample > *series)

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.

Protected Member Functions inherited from QwtPlotItem

QwtGraphic defaultIcon (const QBrush &, const QSizeF &) const
Return a default icon from a brush.

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.

QwtPlotVectorField::˜QwtPlotVectorField () [virtual]

Destructor.

Definition at line 309 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::dataChanged () [override], [protected],[virtual]

dataChanged() indicates, that the series has been changed.

Reimplemented from QwtPlotSeriesItem.

Definition at line 1034 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, doubley, 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, boolon = 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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Updated 2026-06-01 - jenkler.se | uex.se