This graph plots a vector field, i.e. a set of vectors (dx,dy) or (angle,length) at positions (x,y). This class immplements the most basic form of vector plot, i.e. the vector are drawn with a length corresponding to their magnitude. More...

#include <jkqtpvectorfield.h>

Inheritance diagram for JKQTPVectorFieldGraph:

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Collaboration diagram for JKQTPVectorFieldGraph:

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Public Types
enum	VectorAnchorPoint { AnchorBottom , AnchorMid , AnchorTip }
	indicates the position of the point (x,y) relative to the vector More...
enum	VectorLengthMode { AutoscaleLength , LengthFromData , IgnoreLength }
	indicates how the drawn vector's length is calculated from the data More...
enum	VectorLineWidthMode { DefaultVectorLineWidth , AutoscaleLineWidthFromLength }
	describes how the line width scales with the vector properties (or not) More...
Public Types inherited from JKQTPXYAndVectorGraph
enum	VectorDataLayout { DeltaXDeltaYLayout , AngleAndLengthLayout , DefaultVectorDataLayout =DeltaXDeltaYLayout }
	values from this enum indicates how to interpret the data columns provided to this graph More...
Public Types inherited from JKQTPXYGraph
enum	DataSortOrder { Unsorted =0 , SortedX =1 , SortedY =2 }
	specifies how to sort the data in a JKQTPXYGraph before drawing More...
Public Types inherited from JKQTPPlotElement
enum	HitTestMode { HitTestXY , HitTestXOnly , HitTestYOnly }
	modes of operation for the function hitTest() More...

Public Member Functions
	JKQTPVectorFieldGraph (JKQTBasePlotter *parent=nullptr)
	class constructor
	JKQTPVectorFieldGraph (JKQTPlotter *parent)
	class constructor
virtual void	draw (JKQTPEnhancedPainter &painter) override
	plots the graph to the plotter object specified as parent
virtual void	drawKeyMarker (JKQTPEnhancedPainter &painter, const QRectF &rect) override
	plots a key marker inside the specified rectangle rect
VectorAnchorPoint	getAnchorPoint () const
	defines where the vector is anchored
double	getAutoscaleLengthFactor () const
	a scaling factor that can be used to modify the result of the autoscaling algorithm (m_vectorLengthMode `==AutoscaleLength`)
virtual QColor	getKeyLabelColor () const override
	returns the color to be used for the key label
double	getLengthScaleFactor () const
	if m_vectorLengthMode `==false`, this is the scale-factor used to calculate the vector length
double	getMinLineWIdth () const
	minimum line-width in pt, used for some modes of m_vectorLineWidthMode
VectorLengthMode	getVectorLengthMode () const
	indicates how the length of the drawn vectors are determined from the data
VectorLineWidthMode	getVectorLineWidthMode () const
	determines how the line width of the vectors is derived.
void	setAnchorPoint (VectorAnchorPoint newAnchorPoint)
	defines where the vector is anchored
void	setAutoscaleLengthFactor (double newAutoscaleLengthFactor)
	a scaling factor that can be used to modify the result of the autoscaling algorithm (m_vectorLengthMode `==AutoscaleLength`)
void	setLengthScaleFactor (double newLengthScaleFactor)
	if m_vectorLengthMode `==false`, this is the scale-factor used to calculate the vector length
void	setMinLineWidth (double lw)
	minimum line-width in pt, used for some modes of m_vectorLineWidthMode
void	setVectorLengthMode (VectorLengthMode newMode)
	indicates how the length of the drawn vectors are determined from the data
void	setVectorLineWidthMode (VectorLineWidthMode m)
	determines how the line width of the vectors is derived.
Public Member Functions inherited from JKQTPXYAndVectorGraph
	JKQTPXYAndVectorGraph (JKQTBasePlotter *parent=nullptr)
	class constructor
virtual QString	formatHitTestDefaultLabel (double x, double y, int index=-1, const JKQTPDatastore *datastore=nullptr) const override
	tool-function for hitTest(), which formats a default label, taking into account the x- and y-position (both provided) and optionally the errors of these positions.
int	getAngleColumn () const
	the column that contains the rotation angle [in radian]
int	getDxColumn () const
	the column that contains the delta along the x-axis.
int	getDyColumn () const
	the column that contains the delta along the y-axis.
int	getLengthColumn () const
	the column that contains the vector length
VectorDataLayout	getVectorDataLayout () const
	indicates, which column pairs to use (dxColumn, dyColumn), (angleColumn, lengthColumn), ...
virtual bool	getXMinMax (double &minx, double &maxx, double &smallestGreaterZero) override
	get the maximum and minimum x-value of the graph
virtual bool	getYMinMax (double &miny, double &maxy, double &smallestGreaterZero) override
	get the maximum and minimum y-value of the graph
virtual double	hitTest (const QPointF &posSystem, QPointF closestSpotSystem=nullptr, QString label=nullptr, HitTestMode mode=HitTestXY) const override
	Implmentation of JKQTPPlotElement::hitTest(), which searches through all graph points defined by xColumn and yColumn and returns a general x/y-label, also taking into account possibly known errors to the graphs (if it is derived from JKQTPXGraphErrorData and/or JKQTPYGraphErrorData.
virtual bool	usesColumn (int column) const override
	returns `true` if the given column is used by the graph
Public Member Functions inherited from JKQTPXYGraph
	JKQTPXYGraph (JKQTBasePlotter *parent=nullptr)
	class constructor
DataSortOrder	getDataSortOrder () const
	if `!=Unsorted`, the data is sorted before plotting
virtual int	getKeyColumn () const
	returns the column used as "key" for the current graph (typically this call getXColumn(), but for horizontal graphs like filled curves or barcharts it may call getYColumn() )
virtual int	getValueColumn () const
	returns the column used as "value" for the current graph (typically this call getXColumn(), but for horizontal graphs like filled curves or barcharts it may call getYColumn() )
int	getXColumn () const
	the column that contains the x-component of the datapoints
int	getYColumn () const
	the column that contains the y-component of the datapoints
Public Member Functions inherited from JKQTPGraph
	JKQTPGraph (JKQTBasePlotter *parent=nullptr)
	class constructor
virtual	~JKQTPGraph ()=default
	default wirtual destructor
Public Member Functions inherited from JKQTPPlotElement
	JKQTPPlotElement (JKQTBasePlotter *parent=nullptr)
	class constructor
virtual	~JKQTPPlotElement ()=default
	default wirtual destructor
QPointF	backTransform (const QPointF &x) const
	tool routine that back-transforms a QPointF according to the parent's transformation rules (pixels --> plot coordinate)
QPointF	backTransform (double x, double y) const
	tool routine that back-transforms a QPointF according to the parent's transformation rules (pixels --> plot coordinate)
double	backtransformX (double x) const
	tool routine that backtransforms an x-coordinate (pixels --> plot coordinate) for this plot element, uses the axis referenced in xAxisRef
double	backtransformY (double y) const
	tool routine that backtransforms a y-coordinate (pixels --> plot coordinate) for this plot element, uses the axis referenced in yAxisRef
virtual void	drawOutside (JKQTPEnhancedPainter &painter, QRect leftSpace, QRect rightSpace, QRect topSpace, QRect bottomSpace)
	plots outside the actual plot field of view (e.g. color bars, scale bars, ...)
QImage	generateKeyMarker (QSize size=QSize(16, 16))
	returns an image with a key marker inside
virtual void	getOutsideSize (JKQTPEnhancedPainter &painter, int &leftSpace, int &rightSpace, int &topSpace, int &bottomSpace)
	if the graph plots outside the actual plot field of view (e.g. color bars, scale bars, ...)
JKQTBasePlotter *	getParent ()
	returns the parent painter class
const JKQTBasePlotter *	getParent () const
	returns the parent painter class
QString	getTitle () const
	returns the the title of the plot
const JKQTPCoordinateAxis *	getXAxis () const
	returns the actual x-Axis-object from the parent plotter, referenced in xAxisRef
JKQTPCoordinateAxisRef	getXAxisRef () const
	indicates which coordinate axis to use for coordinate transforms in x-direction
const JKQTPCoordinateAxis *	getYAxis () const
	returns the actual y-Axis-object from the parent plotter, referenced in yAxisRef
JKQTPCoordinateAxisRef	getYAxisRef () const
	indicates which coordinate axis to use for coordinate transforms in y-direction
bool	isHighlighted () const
	returns whether the graph is shown in a highlighted style in the plot
bool	isVisible () const
	returns whether the graph is visible in the plot
void	setAxes (JKQTPCoordinateAxisRef ref)
	set the coordinate axes to use for this plot element
virtual void	setParent (JKQTBasePlotter *parent)
	sets the parent painter class
virtual void	setParent (JKQTPlotter *parent)
	sets the parent painter class
void	setXAxis (JKQTPCoordinateAxisRef ref)
	indicates which coordinate axis to use for coordinate transforms in x-direction
void	setYAxis (JKQTPCoordinateAxisRef ref)
	indicates which coordinate axis to use for coordinate transforms in y-direction
QPointF	transform (const QPointF &x) const
	tool routine that transforms a QPointF according to the parent's transformation rules (plot coordinate --> pixels)
QPolygonF	transform (const QPolygonF &x) const
	tool routine that transforms a QPolygonF according to the parent's transformation rules (plot coordinate --> pixels)
QPointF	transform (double x, double y) const
	tool routine that transforms a QPointF according to the parent's transformation rules (plot coordinate --> pixels)
QPainterPath	transformToLinePath (const QPolygonF &x) const
	tool routine that transforms a QPolygonF according to the parent's transformation rules and returns a (non-closed) path consisting of lines (plot coordinate --> pixels)
QVector< double >	transformX (const QVector< double > &x) const
	transform all x-coordinates in a vector x
double	transformX (double x) const
	tool routine that transforms an x-coordinate (plot coordinate --> pixels) for this plot element, uses the axis referenced in xAxisRef
QVector< double >	transformY (const QVector< double > &x) const
	transform all y-coordinates in a vector x
double	transformY (double y) const
	tool routine that transforms a y-coordinate (plot coordinate --> pixels) for this plot element, uses the axis referenced in yAxisRef
Public Member Functions inherited from JKQTPGraphDecoratedLineStyleMixin
	JKQTPGraphDecoratedLineStyleMixin ()
	class constructor
virtual	~JKQTPGraphDecoratedLineStyleMixin ()
double	calcHeadDecoratorSize (double line_width) const
	calculates the tail decorator size from the line width line_width, using m_headDecoratorSizeFactor and a non-linear scaling function
double	calcTailDecoratorSize (double line_width) const
	calculates the tail decorator size from the line width line_width, using m_tailDecoratorSizeFactor and a non-linear scaling function
double	getHeadDecoratorSizeFactor () const
	head decorator size-factor, used to calculate the size of the arrow from the line width
JKQTPLineDecoratorStyle	getHeadDecoratorStyle () const
	get the head decorator style
double	getTailDecoratorSizeFactor () const
	tail decorator size-factor, used to calculate the size of the arrow from the line width
JKQTPLineDecoratorStyle	getTailDecoratorStyle () const
	get the tail decorator style
void	initDecoratedLineStyle (JKQTBasePlotter *parent, int &parentPlotStyle, JKQTPPlotStyleType styletype=JKQTPPlotStyleType::Default)
	initiaize the line style (from the parent plotter)
void	setHeadDecoratorSizeFactor (const double &__value)
	head decorator size-factor, used to calculate the size of the arrow from the line width
void	setHeadDecoratorStyle (const JKQTPLineDecoratorStyle &__value)
	set the head decorator style
void	setTailDecoratorSizeFactor (const double &__value)
	tail decorator size-factor, used to calculate the size of the arrow from the line width
void	setTailDecoratorStyle (const JKQTPLineDecoratorStyle &__value)
	set the tail decorator style
Public Member Functions inherited from JKQTPGraphLineStyleMixin
	JKQTPGraphLineStyleMixin ()
	class constructor
virtual	~JKQTPGraphLineStyleMixin ()
QColor	getHighlightingLineColor () const
	get the color of the graph line when highlighted
QPen	getHighlightingLinePen (JKQTPEnhancedPainter &painter, JKQTBasePlotter *parent) const
	constructs a QPen from the line styling properties
QPen	getHighlightingLinePenForRects (JKQTPEnhancedPainter &painter, JKQTBasePlotter *parent) const
	constructs a QPen from the line styling properties, suitable for drawing rectangle with sharp corners
QPen	getKeyLinePen (JKQTPEnhancedPainter &painter, const QRectF &rect, JKQTBasePlotter *parent) const
	constructs a QPen from the line styling properties, but uses getKeyLineWidthPx() for the width, i.e. constructs a pen for drawing lines in key-symbols
double	getKeyLineWidthPx (JKQTPEnhancedPainter &painter, const QRectF &keyRect, const JKQTBasePlotter *parent) const
	returns the linewidth for drawing lines in a key entry with keyRect for the symbol, using painter and parent .
QBrush	getLineBrush () const
	gets the brush used to fill the line area
Qt::PenCapStyle	getLineCapStyle () const
	gets the cap style
QColor	getLineColor () const
	get the color of the graph line
qreal	getLineDashOffset () const
	returns the dash offset for a custom dash style
QVector< qreal >	getLineDashPattern () const
	gets the dash pattern for a custom dash style
Qt::PenJoinStyle	getLineJoinStyle () const
	returns the join style
QPen	getLinePen (JKQTPEnhancedPainter &painter, JKQTBasePlotter *parent) const
	constructs a QPen from the line styling properties
QPen	getLinePenForRects (JKQTPEnhancedPainter &painter, JKQTBasePlotter *parent) const
	constructs a QPen from the line styling properties, suitable for drawing rectangles with sharp edges
Qt::PenStyle	getLineStyle () const
	get the style of the graph line
double	getLineWidth () const
	get the line width of the graph line (in pt)
void	initLineStyle (JKQTBasePlotter *parent, int &parentPlotStyle, JKQTPPlotStyleType styletype=JKQTPPlotStyleType::Default)
	initiaize the line style (from the parent plotter)
void	setHighlightingLineColor (const QColor &__value)
	set the color of the graph line when highlighted
void	setHighlightingLineColor (const QColor &__value, double alpha)
	set the color of the graph line when highlighted
void	setLineBrush (const QBrush &style)
	sets the brush used to fill the line area
void	setLineCapStyle (Qt::PenCapStyle style)
	sets the cap style
void	setLineColor (const QColor &__value)
	set the color of the graph line
void	setLineColor (const QColor &__value, double alpha)
	set the color of the graph line
void	setLineColorInvertedFrom (QColor __noninvertedColor)
	sets the line-color as an inverted version of the given color
void	setLineDashOffset (qreal offset)
	sets the dash offset for a custom dash style
void	setLineDashPattern (const QVector< qreal > &pattern)
	sets the dash pattern for a custom dash style
void	setLineJoinStyle (Qt::PenJoinStyle style)
	sets the join style
void	setLineStyle (Qt::PenStyle __value)
	set the style of the graph line
void	setLineWidth (double __value)
	set the line width of the graph line (in pt)

Protected Member Functions
virtual QColor	getLocalVectorColor (int i, double x, double y, double dx, double dy) const
	internal color functor, a customization point for derived classes
double	getMaxVecLen () const
	acess to internally calculated (before draw() actually draws) maximum vector length
double	getMinVecLen () const
	acess to internally calculated (before draw() actually draws) minimum vector length
Protected Member Functions inherited from JKQTPXYAndVectorGraph
virtual bool	getIndexRange (int &imin, int &imax) const override
	determines the range of row indexes available in the data columns of this graph
double	getVectorAngle (int i) const
QPointF	getVectorDxDy (int i) const
	this function interprets vectorDataLayout together with (dxColumn, dyColumn) or (angleColumn, lengthColumn) or ... and returns the i -th vectors $\Delta x, \Delta y$
double	getVectorMagnitude (int i) const
Protected Member Functions inherited from JKQTPXYGraph
int	getDataIndex (int i) const
	returns the index of the i-th datapoint (where i is an index into the SORTED datapoints)
virtual void	intSortData ()
	sorts data according to the specified criterion in sortData ... The result is stored as a index-map in sorted Indices
Protected Member Functions inherited from JKQTPGraph
virtual void	drawErrorsAfter (JKQTPEnhancedPainter &)
	this function is used to plot error inidcators after plotting the graphs.
virtual void	drawErrorsBefore (JKQTPEnhancedPainter &)
	this function is used to plot error inidcators before plotting the graphs.
bool	getDataMinMax (int column, double &minx, double &maxx, double &smallestGreaterZero)
	get the maximum and minimum value of the given column
Protected Member Functions inherited from JKQTPPlotElement
void	addHitTestData (const HitTestLocation &loc)
	clear the internal datastore for hitTest()
void	addHitTestData (const QPointF &pos_, const QString &label_)
	clear the internal datastore for hitTest()
void	addHitTestData (const QPointF &pos_, int index_, const QString &label_)
	clear the internal datastore for hitTest()
void	addHitTestData (const QPointF &pos_, int index_=-1, const JKQTPDatastore *datastore=nullptr)
	clear the internal datastore for hitTest(), this variant uses formatHitTestDefaultLabel() to auto-generate the label
void	addHitTestData (double x_, double y_, const QString &label_)
	add a new point on the graph to the internal datastore for hitTest()
void	addHitTestData (double x_, double y_, int index_, const QString &label_)
	clear the internal datastore for hitTest()
void	addHitTestData (double x_, double y_, int index_=-1, const JKQTPDatastore *datastore=nullptr)
	add a new point on the graph to the internal datastore for hitTest(), this variant uses formatHitTestDefaultLabel() to auto-generate the label
void	clearHitTestData ()
	clear the internal datastore for hitTest()
void	reserveHitTestData (int points)
	reserve list entries for up to points graph points in the internal datastore for hitTest()
QString	xFloatToString (double v, int past_comma=-1) const
	converts a x-value v into a string, taking into account the type of x-axis
QString	yFloatToString (double v, int past_comma=-1) const
	converts a x-value v into a string, taking into account the type of x-axis

Properties
VectorAnchorPoint	anchorPoint
bool	autoscaleLengthFactor
double	lengthScaleFactor
double	minLineWidth
VectorLengthMode	vectorLengthMode
VectorLineWidthMode	vectorLineWidthMode
Properties inherited from JKQTPXYAndVectorGraph
int	angleColumn
	the column that contains the rotation angle [in radian]
int	dxColumn
	the column that contains the delta along the x-axis.
int	dyColumn
	the column that contains the delta along the y-axis.
int	lengthColumn
	the column that contains the vector length
VectorDataLayout	vectorDataLayout
	indicates, which column pairs to use (dxColumn, dyColumn), (angleColumn, lengthColumn), ...
Properties inherited from JKQTPXYGraph
DataSortOrder	sortData
	if `!=Unsorted`, the data is sorted before plotting
int	xColumn
	the column that contains the x-component of the datapoints
int	yColumn
	the column that contains the y-component of the datapoints
Properties inherited from JKQTPPlotElement
bool	highlighted
	indicates whether the graph is shown in a "highlghted" in the plot
QString	title
	title of the plot (for display in key!). If no title is supplied, no key entry is drawn.
bool	visible
	indicates whether the graph is visible in the plot
JKQTPCoordinateAxisRef	xAxisRef
	indicates which coordinate axis to use for coordinate transforms in x-direction
JKQTPCoordinateAxisRef	yAxisRef
	indicates which coordinate axis to use for coordinate transforms in y-direction
Properties inherited from JKQTPGraphDecoratedLineStyleMixin
double	headDecoratorSizeFactor
JKQTPLineDecoratorStyle	headDecoratorStyle
double	tailDecoratorSizeFactor
JKQTPLineDecoratorStyle	tailDecoratorStyle
Properties inherited from JKQTPGraphLineStyleMixin
QColor	highlightingLineColor
QColor	lineColor
Qt::PenStyle	lineStyle
double	lineWidth

Private Attributes
VectorAnchorPoint	m_anchorPoint
	defines where the vector is anchored
double	m_autoscaleLengthFactor
	a scaling factor that can be used to modify the result of the autoscaling algorithm (m_vectorLengthMode `==AutoscaleLength`)
double	m_lengthScaleFactor
	if m_vectorLengthMode `==false`, this is the scale-factor used to calculate the vector length
double	m_maxVecLen
	internally calculated (before draw() actually draws) maximum vector length
double	m_minLineWidth
	minimum line-width in pt, used for some modes of m_vectorLineWidthMode
double	m_minVecLen
	internally calculated (before draw() actually draws) minimum vector length
VectorLengthMode	m_vectorLengthMode
	indicates how the length of the drawn vectors are determined from the data
VectorLineWidthMode	m_vectorLineWidthMode
	determines how the line width of the vectors is derived.

Additional Inherited Members
Public Slots inherited from JKQTPXYAndVectorGraph
void	setAngleAndLengthColumn (int colAngle, int colLength)
	det angleColumn and lengthColumn column at the same time! ALso ensures that vectorDataLayout is set accordingly.
void	setAngleColumn (int col)
	the column that contains the rotation angle [in radian]
void	setDxColumn (int col)
	the column that contains the delta along the x-axis.
void	setDxDyColumn (int colDx, int colDy)
	det dxColumn and dyColumn column at the same time! ALso ensures that vectorDataLayout is set accordingly.
void	setDyColumn (int col)
	the column that contains the delta along the y-axis.
void	setLengthColumn (int col)
	the column that contains the vector length
Public Slots inherited from JKQTPXYGraph
void	setDataSortOrder (DataSortOrder __value)
	if `!=Unsorted`, the data is sorted before plotting
void	setDataSortOrder (int __value)
	if `!=Unsorted`, the data is sorted before plotting
virtual void	setKeyColumn (int __value)
	sets the column used as "key" for the current graph (typically this call setXColumn(), but for horizontal graphs like filled curves or barcharts it may call setYColumn() )
virtual void	setValueColumn (int __value)
	sets the column used as "value" for the current graph (typically this call setXColumn(), but for horizontal graphs like filled curves or barcharts it may call setYColumn() )
void	setXColumn (int __value)
	the column that contains the x-component of the datapoints
void	setXColumn (size_t __value)
	the column that contains the x-component of the datapoints
void	setXYColumns (int xCol, int yCol)
	sets xColumn and yColumn at the same time
void	setXYColumns (QPair< int, int > xyColPair)
	sets xColumn and yColumn at the same time
void	setXYColumns (QPair< size_t, size_t > xyColPair)
	sets xColumn and yColumn at the same time
void	setXYColumns (size_t xCol, size_t yCol)
	sets xColumn and yColumn at the same time
void	setYColumn (int __value)
	the column that contains the y-component of the datapoints
void	setYColumn (size_t __value)
	the column that contains the y-component of the datapoints
Public Slots inherited from JKQTPPlotElement
void	setHighlighted (bool __value)
	sets whether the graph is drawn in a highlighted style in the plot
virtual void	setTitle (const QString &__value)
	sets the title of the plot (for display in key!).
void	setVisible (bool __value)
	sets whether the graph is visible in the plot
Static Protected Member Functions inherited from JKQTPXYAndVectorGraph
static double	getVectorAngle (const QPointF &v)
	calculates the rotation angle (3 o'clock is 0) in radians $[0...2\pi]$ of a vector v
static double	getVectorMagnitude (const QPointF &v)
	calculates the magnitude/length of a vector v
Protected Attributes inherited from JKQTPXYGraph
QVector< int >	sortedIndices
	this array contains the order of indices, in which to access the data in the data columns
Protected Attributes inherited from JKQTPPlotElement
QVector< HitTestLocation >	m_hitTestData
	dataset with graph-points and associated data from the function hitTest()
JKQTBasePlotter *	parent
	the plotter object this object belongs to
int	parentPlotStyle
	internal storage for the used parent plot style

Detailed Description

This graph plots a vector field, i.e. a set of vectors (dx,dy) or (angle,length) at positions (x,y). This class immplements the most basic form of vector plot, i.e. the vector are drawn with a length corresponding to their magnitude.

Note: This type of plot is sometimes also refered to as quiver plot (e.g. in Matlab or matplotlib)

To achieve this, use code like this:

// 1. setup a plotter window and get a pointer to the internal datastore (for convenience)
JKQTPlotter plot;
JKQTPDatastore* ds=plot.getDatastore();
 
// 2. make up some arbitrary data to be used for plotting
//    this generates a 2D grid of x/y-coordinates and then calculates dx=cos(y)*sqrt(x/3.0) and dy=sin(x)*sqrt(x/3.0)
const auto columnXY=ds->addLinearGridColumns(NX, 0, 6, NY, -3, 3,"x","y");
const auto columnDX=ds->addCalculatedColumnFromColumn(columnXY.first, columnXY.second, [](double x,double y) { return sin(y)*sqrt(x/3.0); });
const auto columnDY=ds->addCalculatedColumnFromColumn(columnXY.first, columnXY.second, [](double x,double y) { return cos(x)*sqrt(x/3.0); });
 
// 3. create JKQTPVectorFieldGraph to display the data:
JKQTPVectorFieldGraph* graph1=new JKQTPVectorFieldGraph(&plot);
graph1->setXYColumns(columnXY);
graph1->setDxColumn(columnDX);
graph1->setDyColumn(columnDY);
graph1->setTitle(QObject::tr("$\\vec{f}(x,y)=\\bigl[\\sin(y)\\cdot\\sqrt{x/3}, \\cos(x)\\cdot\\sqrt{x/3}\\bigr]^\\mathrm{T}$"));
 
// 4. add the graphs to the plot, so it is actually displayed
plot.addGraph(graph1);

You have several options to influence the way the vectors are drawn:

You can change the tip shape (and actually also the tail) of the vector by using the methods from JKQTPGraphDecoratedLineStyleMixin, e.g. use JKQTPGraphDecoratedLineStyleMixin::setHeadDecoratorStyle() to set another shape for the vector's tip, or modify JKQTPGraphDecoratedLineStyleMixin::setHeadDecoratorSizeFactor() to modify the size of the vector's head. the vector line width, color etz. can be modified by the methods from JKQTPGraphLineStyleMixin, like JKQTPGraphLineStyleMixin::setLineColor() or JKQTPGraphLineStyleMixin::setLineWidth().
By default the length of the drawn vectors corresponds to the actual length of the vector data, but is modified by an autoscaling algorithm that should prevent them from overlapping. This behaviour can be changed by setVectorLengthMode() with the different options described in VectorLengthMode.
By default, vector start at (x,y). But you can also make them be centered around or point to (x,y) . This can be set by setAnchorPoint().
Using setVectorLineWidthMode(JKQTPVectorFieldGraph::AutoscaleLineWidthFromLength) you can also scale the line width of each vector by the vector's length. This sometimes gives an easier to read representation of the vector properties, especially if combined with setVectorLengthMode(JKQTPVectorFieldGraph::IgnoreLength) :

See also: Example (JKQTPlotter): Vector Field Plot Example , JKQTPGraphDecoratedLineStyleMixin , JKQTPXYAndVectorGraph and JKQTPParametrizedVectorFieldGraph for a user-colored alternative

Member Enumeration Documentation

◆ VectorAnchorPoint

enum JKQTPVectorFieldGraph::VectorAnchorPoint

indicates the position of the point (x,y) relative to the vector

Enumerator
AnchorBottom	this is the default: the vector starts at (x,y)
AnchorMid	the vector's mid is at (x,y)
AnchorTip	the vector ends at (x,y)

◆ VectorLengthMode

enum JKQTPVectorFieldGraph::VectorLengthMode

indicates how the drawn vector's length is calculated from the data

See also: documentation of m_vectorLengthMode for details

Enumerator
AutoscaleLength	this is the default: vector lengths are autoscaled, so they don't overlap (in first approximation)
LengthFromData	the vector's length is determined by the data directly
IgnoreLength	all vectors have the same length

◆ VectorLineWidthMode

enum JKQTPVectorFieldGraph::VectorLineWidthMode

describes how the line width scales with the vector properties (or not)

Enumerator
DefaultVectorLineWidth	line width is equal to JKQTPGraphLineStyleMixin::getLineWidth() for all vectors
AutoscaleLineWidthFromLength	line width is determined from the vector length. The maximum line width is given by JKQTPGraphLineStyleMixin::getLineWidth() and the minim line width by getMinLineWidth()

Constructor & Destructor Documentation

◆ JKQTPVectorFieldGraph() [1/2]

JKQTPVectorFieldGraph::JKQTPVectorFieldGraph ( JKQTBasePlotter * parent = nullptr )

explicit

class constructor

◆ JKQTPVectorFieldGraph() [2/2]

JKQTPVectorFieldGraph::JKQTPVectorFieldGraph ( JKQTPlotter * parent )

class constructor

Member Function Documentation

◆ draw()

virtual void JKQTPVectorFieldGraph::draw ( JKQTPEnhancedPainter & painter )

overridevirtual

plots the graph to the plotter object specified as parent

Implements JKQTPPlotElement.

Reimplemented in JKQTPParametrizedVectorFieldGraph.

◆ drawKeyMarker()

virtual void JKQTPVectorFieldGraph::drawKeyMarker	(	JKQTPEnhancedPainter &	painter,
		const QRectF &	rect )

overridevirtual

plots a key marker inside the specified rectangle rect

Implements JKQTPPlotElement.

Reimplemented in JKQTPParametrizedVectorFieldGraph.

◆ getAnchorPoint()

VectorAnchorPoint JKQTPVectorFieldGraph::getAnchorPoint ( ) const

defines where the vector is anchored

See also: VectorAnchorPoint, setAnchorPoint(), getAnchorPoint()

◆ getAutoscaleLengthFactor()

double JKQTPVectorFieldGraph::getAutoscaleLengthFactor ( ) const

a scaling factor that can be used to modify the result of the autoscaling algorithm (m_vectorLengthMode ==AutoscaleLength)

The vector length is further scaled by this value.

See also: m_vectorLengthMode, setAutoscaleFactor(), getAutoscaleFactor()

◆ getKeyLabelColor()

virtual QColor JKQTPVectorFieldGraph::getKeyLabelColor ( ) const

overridevirtual

returns the color to be used for the key label

Implements JKQTPPlotElement.

◆ getLengthScaleFactor()

double JKQTPVectorFieldGraph::getLengthScaleFactor ( ) const

if m_vectorLengthMode ==false, this is the scale-factor used to calculate the vector length

See also: setLengthScaleFactor(), getLengthScaleFactor(), m_vectorLengthMode

◆ getLocalVectorColor()

virtual QColor JKQTPVectorFieldGraph::getLocalVectorColor	(	int	i,
		double	x,
		double	y,
		double	dx,
		double	dy ) const

protectedvirtual

internal color functor, a customization point for derived classes

Overwrite this in a derived class to be able to color each vector differently

Reimplemented in JKQTPParametrizedVectorFieldGraph.

◆ getMaxVecLen()

double JKQTPVectorFieldGraph::getMaxVecLen ( ) const

inlineprotected

acess to internally calculated (before draw() actually draws) maximum vector length

◆ getMinLineWIdth()

double JKQTPVectorFieldGraph::getMinLineWIdth ( ) const

minimum line-width in pt, used for some modes of m_vectorLineWidthMode

See also: setMinLineWidth(), getMinLineWidth(), m_vectorLineWidthMode

◆ getMinVecLen()

double JKQTPVectorFieldGraph::getMinVecLen ( ) const

inlineprotected

acess to internally calculated (before draw() actually draws) minimum vector length

◆ getVectorLengthMode()

VectorLengthMode JKQTPVectorFieldGraph::getVectorLengthMode ( ) const

indicates how the length of the drawn vectors are determined from the data

Several modes are possible:

If == LengthFromData the vector is drawn from (x,y) to (x+dx,y+dy)*m_lengthScaleFactor.
If == AutoscaleLength the vector is drawn to (x+dx,y+dy)*autoscale*m_autoscaleLengthFactor . The autoscaled length is calculated by a simple algorithm that uses the 90% quantile of vector length in the data q90VectorLength : autoscale=plotwidth/VectorPerWidth/q90VectorLength .
If == IgnoreLength all vectors are drawn with the same length, which is determined from autoscale*m_autoscaleLengthFactor where autoscale is defined as above.

See also: VectorLengthMode, setVectorLengthMode(), getVectorLengthMode(), m_lengthScaleFactor, m_autoscaleLengthFactor

◆ getVectorLineWidthMode()

VectorLineWidthMode JKQTPVectorFieldGraph::getVectorLineWidthMode ( ) const

determines how the line width of the vectors is derived.

Note: the available options are described with VectorLineWidthMode

See also: setVectorLineWidthMode(), getVectorLineWidthMode(), VectorLineWidthMode, m_minLineWidth

◆ setAnchorPoint()

void JKQTPVectorFieldGraph::setAnchorPoint ( VectorAnchorPoint newAnchorPoint )

defines where the vector is anchored

See also: VectorAnchorPoint, setAnchorPoint(), getAnchorPoint()

◆ setAutoscaleLengthFactor()

void JKQTPVectorFieldGraph::setAutoscaleLengthFactor ( double newAutoscaleLengthFactor )

a scaling factor that can be used to modify the result of the autoscaling algorithm (m_vectorLengthMode ==AutoscaleLength)

The vector length is further scaled by this value.

See also: m_vectorLengthMode, setAutoscaleFactor(), getAutoscaleFactor()

◆ setLengthScaleFactor()

void JKQTPVectorFieldGraph::setLengthScaleFactor ( double newLengthScaleFactor )

if m_vectorLengthMode ==false, this is the scale-factor used to calculate the vector length

See also: setLengthScaleFactor(), getLengthScaleFactor(), m_vectorLengthMode

◆ setMinLineWidth()

void JKQTPVectorFieldGraph::setMinLineWidth ( double lw )

minimum line-width in pt, used for some modes of m_vectorLineWidthMode

See also: setMinLineWidth(), getMinLineWidth(), m_vectorLineWidthMode

◆ setVectorLengthMode()

void JKQTPVectorFieldGraph::setVectorLengthMode ( VectorLengthMode newMode )

indicates how the length of the drawn vectors are determined from the data

Several modes are possible:

If == LengthFromData the vector is drawn from (x,y) to (x+dx,y+dy)*m_lengthScaleFactor.
If == AutoscaleLength the vector is drawn to (x+dx,y+dy)*autoscale*m_autoscaleLengthFactor . The autoscaled length is calculated by a simple algorithm that uses the 90% quantile of vector length in the data q90VectorLength : autoscale=plotwidth/VectorPerWidth/q90VectorLength .
If == IgnoreLength all vectors are drawn with the same length, which is determined from autoscale*m_autoscaleLengthFactor where autoscale is defined as above.

See also: VectorLengthMode, setVectorLengthMode(), getVectorLengthMode(), m_lengthScaleFactor, m_autoscaleLengthFactor

◆ setVectorLineWidthMode()

void JKQTPVectorFieldGraph::setVectorLineWidthMode ( VectorLineWidthMode m )

determines how the line width of the vectors is derived.

Note: the available options are described with VectorLineWidthMode

See also: setVectorLineWidthMode(), getVectorLineWidthMode(), VectorLineWidthMode, m_minLineWidth

Member Data Documentation

◆ m_anchorPoint

VectorAnchorPoint JKQTPVectorFieldGraph::m_anchorPoint

private

defines where the vector is anchored

See also: VectorAnchorPoint, setAnchorPoint(), getAnchorPoint()

◆ m_autoscaleLengthFactor

double JKQTPVectorFieldGraph::m_autoscaleLengthFactor

private

a scaling factor that can be used to modify the result of the autoscaling algorithm (m_vectorLengthMode ==AutoscaleLength)

The vector length is further scaled by this value.

See also: m_vectorLengthMode, setAutoscaleFactor(), getAutoscaleFactor()

◆ m_lengthScaleFactor

double JKQTPVectorFieldGraph::m_lengthScaleFactor

private

if m_vectorLengthMode ==false, this is the scale-factor used to calculate the vector length

See also: setLengthScaleFactor(), getLengthScaleFactor(), m_vectorLengthMode

◆ m_maxVecLen

double JKQTPVectorFieldGraph::m_maxVecLen

private

internally calculated (before draw() actually draws) maximum vector length

◆ m_minLineWidth

double JKQTPVectorFieldGraph::m_minLineWidth

private

minimum line-width in pt, used for some modes of m_vectorLineWidthMode

See also: setMinLineWidth(), getMinLineWidth(), m_vectorLineWidthMode

◆ m_minVecLen

double JKQTPVectorFieldGraph::m_minVecLen

private

internally calculated (before draw() actually draws) minimum vector length

◆ m_vectorLengthMode

VectorLengthMode JKQTPVectorFieldGraph::m_vectorLengthMode

private

indicates how the length of the drawn vectors are determined from the data

Several modes are possible:

If == LengthFromData the vector is drawn from (x,y) to (x+dx,y+dy)*m_lengthScaleFactor.
If == AutoscaleLength the vector is drawn to (x+dx,y+dy)*autoscale*m_autoscaleLengthFactor . The autoscaled length is calculated by a simple algorithm that uses the 90% quantile of vector length in the data q90VectorLength : autoscale=plotwidth/VectorPerWidth/q90VectorLength .
If == IgnoreLength all vectors are drawn with the same length, which is determined from autoscale*m_autoscaleLengthFactor where autoscale is defined as above.

See also: VectorLengthMode, setVectorLengthMode(), getVectorLengthMode(), m_lengthScaleFactor, m_autoscaleLengthFactor

◆ m_vectorLineWidthMode

VectorLineWidthMode JKQTPVectorFieldGraph::m_vectorLineWidthMode

private

determines how the line width of the vectors is derived.

Note: the available options are described with VectorLineWidthMode

See also: setVectorLineWidthMode(), getVectorLineWidthMode(), VectorLineWidthMode, m_minLineWidth

Property Documentation

◆ anchorPoint

VectorAnchorPoint JKQTPVectorFieldGraph::anchorPoint

readwrite

◆ autoscaleLengthFactor

bool JKQTPVectorFieldGraph::autoscaleLengthFactor

readwrite

◆ lengthScaleFactor

double JKQTPVectorFieldGraph::lengthScaleFactor

readwrite

◆ minLineWidth

double JKQTPVectorFieldGraph::minLineWidth

readwrite

◆ vectorLengthMode

VectorLengthMode JKQTPVectorFieldGraph::vectorLengthMode

readwrite

◆ vectorLineWidthMode

VectorLineWidthMode JKQTPVectorFieldGraph::vectorLineWidthMode

readwrite

The documentation for this class was generated from the following file:

jkqtpvectorfield.h

Public Types

Public Member Functions

Protected Member Functions

Properties

Private Attributes

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ VectorAnchorPoint

◆ VectorLengthMode

◆ VectorLineWidthMode

Constructor & Destructor Documentation

◆ JKQTPVectorFieldGraph() [1/2]

◆ JKQTPVectorFieldGraph() [2/2]

Member Function Documentation

◆ draw()

◆ drawKeyMarker()

◆ getAnchorPoint()

◆ getAutoscaleLengthFactor()

◆ getKeyLabelColor()

◆ getLengthScaleFactor()

◆ getLocalVectorColor()

◆ getMaxVecLen()

◆ getMinLineWIdth()

◆ getMinVecLen()

◆ getVectorLengthMode()

◆ getVectorLineWidthMode()

◆ setAnchorPoint()

◆ setAutoscaleLengthFactor()

◆ setLengthScaleFactor()

◆ setMinLineWidth()

◆ setVectorLengthMode()

◆ setVectorLineWidthMode()

Member Data Documentation

◆ m_anchorPoint

◆ m_autoscaleLengthFactor

◆ m_lengthScaleFactor

◆ m_maxVecLen

◆ m_minLineWidth

◆ m_minVecLen

◆ m_vectorLengthMode

◆ m_vectorLineWidthMode

Property Documentation

◆ anchorPoint

◆ autoscaleLengthFactor

◆ lengthScaleFactor

◆ minLineWidth

◆ vectorLengthMode

◆ vectorLineWidthMode