JKQTPlotter trunk/v5.0.0
an extensive Qt5+Qt6 Plotter framework (including a feature-richt plotter widget, a speed-optimized, but limited variant and a LaTeX equation renderer!), written fully in C/C++ and without external dependencies
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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, ...)
 
JKQTBasePlottergetParent ()
 returns the parent painter class
 
const JKQTBasePlottergetParent () const
 returns the parent painter class
 
QString getTitle () const
 returns the the title of the plot

 
const JKQTPCoordinateAxisgetXAxis () 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 JKQTPCoordinateAxisgetYAxis () 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< HitTestLocationm_hitTestData
 dataset with graph-points and associated data from the function hitTest()
 
JKQTBasePlotterparent
 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)
// 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:
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);
This class manages data columns (with entries of type double ), used by JKQTPlotter/JKQTBasePlotter t...
Definition jkqtpdatastorage.h:282
std::pair< size_t, size_t > addLinearGridColumns(size_t width, double startX, double endX, size_t height, double startY, double endY, const QString &nameX=QString(""), const QString &nameY=QString(""))
add two columns to the datastore that contains the x- and y- coordinates of a rectangular grid with w...
size_t addCalculatedColumnFromColumn(size_t otherColumn, const std::function< double(double)> &f, const QString &name=QString(""))
add a column with the same number of entries, as in the other column otherColumn ,...
virtual void setTitle(const QString &__value)
sets the title of the plot (for display in key!).
This graph plots a vector field, i.e. a set of vectors (dx,dy) or (angle,length) at positions (x,...
Definition jkqtpvectorfield.h:96
void setDyColumn(int col)
the column that contains the delta along the y-axis.
void setDxColumn(int col)
the column that contains the delta along the x-axis.
void setXYColumns(size_t xCol, size_t yCol)
sets xColumn and yColumn at the same time
plotter widget for scientific plots (uses JKQTBasePlotter to do the actual drawing)
Definition jkqtplotter.h:364
size_t addGraph(JKQTPPlotElement *gr)
Definition jkqtplotter.h:784
JKQTPDatastore * getDatastore()
returns a pointer to the datastore used by this object
Definition jkqtplotter.h:611

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

  1. 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().
  2. 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.
  3. 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().
  4. 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

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

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

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: