A class for drawing arrow markers on plots. More...

#include <qwt_plot_arrowmarker.h>

Inheritance diagram for QwtPlotArrowMarker:

Classes
class	PrivateData

Public Types
enum	EndpointStyle { NoEndpoint = 0 , ArrowHead , Circle , Square , Diamond , Triangle , CustomPath }
	Arrow endpoint style types. More...

enum	PositionMode { ExplicitPoints , StartLengthAngle }
	Arrow positioning mode. More...

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_PlotArrowMarker , Rtti_PlotBoxChart , Rtti_PlotUserItem = 1000 }
	Runtime type information. More...

enum	ItemAttribute { Legend = 0x01 , AutoScale = 0x02 , Margins = 0x04 }
	Plot Item Attributes. More...

enum	ItemInterest { ScaleInterest = 0x01 , LegendInterest = 0x02 }
	Plot Item Interests. More...

enum	RenderHint { RenderAntialiased = 0x1 }
	Render hints. More...

Public Member Functions
	QwtPlotArrowMarker ()
	Default constructor.

	QwtPlotArrowMarker (const QString &title)

	QwtPlotArrowMarker (const QwtText &title)

virtual int	rtti () const override
	Get the runtime type information.

QPointF	startPoint () const
	Get the start point of the arrow.

QPointF	endPoint () const
	Get the end point of the arrow.

void	setStartPoint (const QPointF &point)
	Set the start point in plot coordinates.

void	setEndPoint (const QPointF &point)
	Set the end point in plot coordinates.

void	setPoints (const QPointF &start, const QPointF &end)
	Set both start and end points in plot coordinates.

double	length () const
	Get the arrow length in pixels.

void	setLength (double length)
	Set the arrow length in pixels.

double	angle () const
	Get the rotation angle in degrees.

void	setAngle (double angle)
	Set the rotation angle in degrees.

PositionMode	positionMode () const
	Get the positioning mode.

void	setPositionMode (PositionMode mode)
	Set the positioning mode.

const QPen &	linePen () const
	Get the arrow line pen.

void	setLinePen (const QPen &pen)
	Set the arrow line pen.

void	setLinePen (const QColor &color, qreal width=1.0, Qt::PenStyle style=Qt::SolidLine)
	Convenience method to set line color and width.

EndpointStyle	headStyle () const
	Get the head style.

void	setHeadStyle (EndpointStyle style)
	Set the head style.

EndpointStyle	tailStyle () const
	Get the tail style.

void	setTailStyle (EndpointStyle style)
	Set the tail style.

QSizeF	headSize () const
	Get the head size in pixels.

void	setHeadSize (const QSizeF &size)
	Set the head size in pixels.

void	setHeadSize (qreal size)
	Convenience method to set head size with equal width and height.

QSizeF	tailSize () const
	Get the tail size in pixels.

void	setTailSize (const QSizeF &size)
	Set the tail size in pixels.

void	setTailSize (qreal size)
	Convenience method to set tail size with equal width and height.

const QBrush &	headBrush () const
	Get the head brush.

void	setHeadBrush (const QBrush &brush)
	Set the head brush.

const QBrush &	tailBrush () const
	Get the tail brush.

void	setTailBrush (const QBrush &brush)
	Set the tail brush.

const QPen &	headPen () const
	Get the head pen.

void	setHeadPen (const QPen &pen)
	Set the head pen.

const QPen &	tailPen () const
	Get the tail pen.

void	setTailPen (const QPen &pen)
	Set the tail pen.

void	setHeadCustomPath (const QPainterPath &path)
	Set a custom path for head endpoint.

QPainterPath	headCustomPath () const
	Get the custom head path.

void	setTailCustomPath (const QPainterPath &path)
	Set a custom path for tail endpoint.

QPainterPath	tailCustomPath () const
	Get the custom tail path.

virtual void	draw (QPainter *painter, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect) const override
	Draw the arrow marker on the plot.

virtual QRectF	boundingRect () const override
	Get the bounding rectangle.

virtual QwtGraphic	legendIcon (int index, const QSizeF &size) const override
	Get the legend icon.

Public Member Functions inherited from QwtPlotItem
	QwtPlotItem ()
	Default constructor.

	QwtPlotItem (const QString &title)
	Constructor with title as QString.

	QwtPlotItem (const QwtText &title)
	Constructor with title as QwtText.

virtual	~QwtPlotItem ()
	Destructor.

virtual void	attach (QwtPlot *plot)
	Attach the item to a plot.

void	detach ()
	Detach the item from the plot.

QwtPlot *	plot () const
	Get the plot the item is attached to.

void	setTitle (const QString &title)
	Set the title using a QString.

void	setTitle (const QwtText &title)
	Set the title using a QwtText.

const QwtText &	title () const
	Get the title.

void	setItemAttribute (ItemAttribute, bool on=true)
	Set an item attribute.

bool	testItemAttribute (ItemAttribute) const
	Test an item attribute.

void	setItemInterest (ItemInterest, bool on=true)
	Set an item interest.

bool	testItemInterest (ItemInterest) const
	Test an item interest.

void	setRenderHint (RenderHint, bool on=true)
	Set a render hint.

bool	testRenderHint (RenderHint) const
	Test a render hint.

void	setRenderThreadCount (uint numThreads)
	Set the number of render threads.

uint	renderThreadCount () const
	Get the number of render threads.

void	setLegendIconSize (const QSize &)
	Set the legend icon size.

QSize	legendIconSize () const
	Get the legend icon size.

double	z () const
	Get the z-value.

void	setZ (double z)
	Set the z-value.

void	show ()
	Show the item.

void	hide ()
	Hide the item.

virtual void	setVisible (bool)
	Set the visibility.

bool	isVisible () const
	Check if the item is visible.

void	setAxes (QwtAxisId xAxis, QwtAxisId yAxis)
	Set both axes.

void	setXAxis (QwtAxisId)
	Set the x-axis.

QwtAxisId	xAxis () const
	Get the x-axis.

void	setYAxis (QwtAxisId)
	Set the y-axis.

QwtAxisId	yAxis () const
	Get the y-axis.

virtual void	itemChanged ()
	Notify the plot that the item has changed.

virtual void	legendChanged ()
	Notify the item that the legend has changed.

virtual void	getCanvasMarginHint (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect, double &left, double &top, double &right, double &bottom) const
	Get margin hints for the canvas.

virtual void	updateScaleDiv (const QwtScaleDiv &, const QwtScaleDiv &)
	Update the item with new scale divisions.

virtual void	updateLegend (const QwtPlotItem *, const QList< QwtLegendData > &)
	Update the item with changes of the legend.

QRectF	scaleRect (const QwtScaleMap &, const QwtScaleMap &) const
	Calculate the scale rectangle.

QRectF	paintRect (const QwtScaleMap &, const QwtScaleMap &) const
	Calculate the paint rectangle.

virtual QList< QwtLegendData >	legendData () const
	Return legend data.

Protected Member Functions
virtual void	drawArrowLine (QPainter *painter, const QPointF &canvasStart, const QPointF &canvasEnd) const
	Draw the arrow line.

virtual void	drawCachedEndpoint (QPainter *painter, const QPointF &position, const QPainterPath &cachedPath, const QSizeF &size, const QPen &pen, const QBrush &brush, double rotation=0.0) const
	Draw a cached endpoint path.

virtual QPointF	toCanvasPoint (const QPointF &plotPoint, const QwtScaleMap &xMap, const QwtScaleMap &yMap) const
	Convert plot coordinates to canvas coordinates.

virtual QPointF	calculateEndPoint () const
	Calculate end point based on start point, length, and angle.

Protected Member Functions inherited from QwtPlotItem
QwtGraphic	defaultIcon (const QBrush &, const QSizeF &) const
	Create a default icon.

Detailed Description

A class for drawing arrow markers on plots.

QwtPlotArrowMarker is a specialized plot item for drawing arrows with customizable start and end points, arrow styles, lengths, and colors. The arrow is drawn in canvas pixel coordinates, maintaining its size during zoom operations while following canvas panning.

Key features:

Support for explicit start and end point specification
Arrow positioning via start point, length, and rotation angle
Customizable arrow head and tail styles
Canvas pixel-based drawing (size preserved during zoom)
Flexible styling system with predefined and custom shapes

Member Enumeration Documentation

◆ EndpointStyle

enum QwtPlotArrowMarker::EndpointStyle

Arrow endpoint style types.

See also: setHeadStyle(), setTailStyle(), headStyle(), tailStyle()

Enumerator
NoEndpoint	No endpoint (invisible)
ArrowHead	Arrow head style.
Circle	Circle endpoint.
Square	Square endpoint.
Diamond	Diamond endpoint.
Triangle	Triangle endpoint.
CustomPath	Custom QPainterPath endpoint.

◆ PositionMode

enum QwtPlotArrowMarker::PositionMode

Arrow positioning mode.

See also: setPositionMode(), positionMode()

Enumerator

ExplicitPoints

Use explicit start and end points.

In this mode, the arrow's start and end points are specified in plot coordinates. The arrow's size will change proportionally to the plot's zoom level.

StartLengthAngle

start point, length, and angle

in this mode, the arrow length will be fixed regardless of the zoom level

Constructor & Destructor Documentation

◆ QwtPlotArrowMarker()

QwtPlotArrowMarker::QwtPlotArrowMarker ( )

explicit

Default constructor.

Creates a new QwtPlotArrowMarker with default settings. The arrow has a length of 50 pixels, angle of 45 degrees, arrow head style, and default colors.

Constructor with title

Parameters

[in] title Title of the marker

Constructor with QwtText title

Parameters

[in] title Title of the marker

Destructor

Member Function Documentation

◆ angle()

double QwtPlotArrowMarker::angle ( ) const

Get the rotation angle in degrees.

Returns: Rotation angle in degrees

◆ boundingRect()

QRectF QwtPlotArrowMarker::boundingRect ( ) const

overridevirtual

Get the bounding rectangle.

Returns: Bounding rectangle

Reimplemented from QwtPlotItem.

◆ draw()

void QwtPlotArrowMarker::draw	(	QPainter *	painter,
		const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap,
		const QRectF &	canvasRect
	)		const

overridevirtual

Draw the arrow marker on the plot.

Parameters

[in]	painter	The painter to use for drawing
[in]	xMap	X-axis scale map for coordinate transformation
[in]	yMap	Y-axis scale map for coordinate transformation
[in]	canvasRect	The canvas rectangle in painter coordinates

This method draws the arrow marker including the line, head, and tail endpoints. It handles both positioning modes (ExplicitPoints and StartLengthAngle) and applies proper rotation to endpoints based on arrow direction.

Implements QwtPlotItem.

◆ drawCachedEndpoint()

void QwtPlotArrowMarker::drawCachedEndpoint	(	QPainter *	painter,
		const QPointF &	position,
		const QPainterPath &	cachedPath,
		const QSizeF &	size,
		const QPen &	pen,
		const QBrush &	brush,
		double	rotation = `0.0`
	)		const

protectedvirtual

Draw a cached endpoint path.

Parameters

[in]	painter	The painter to use for drawing
[in]	position	The position to draw the endpoint at (canvas coordinates)
[in]	cachedPath	The pre-cached QPainterPath for the endpoint
[in]	size	The size of the endpoint in pixels
[in]	pen	The pen to use for drawing the endpoint outline
[in]	brush	The brush to use for filling the endpoint
[in]	rotation	The rotation angle in degrees (0 = positive X direction)

This method draws a cached endpoint path with proper scaling, positioning, and rotation. It is optimized for performance by reusing pre-computed QPainterPath objects.

◆ endPoint()

QPointF QwtPlotArrowMarker::endPoint ( ) const

Get the end point of the arrow.

Returns: End point in plot coordinates

◆ headBrush()

const QBrush & QwtPlotArrowMarker::headBrush ( ) const

Get the head brush.

Returns: Head brush

◆ headCustomPath()

QPainterPath QwtPlotArrowMarker::headCustomPath ( ) const

Get the custom head path.

Returns: Custom head path

◆ headPen()

const QPen & QwtPlotArrowMarker::headPen ( ) const

Get the head pen.

Returns: Head pen

◆ headSize()

QSizeF QwtPlotArrowMarker::headSize ( ) const

Get the head size in pixels.

Returns: Head size in pixels

◆ headStyle()

QwtPlotArrowMarker::EndpointStyle QwtPlotArrowMarker::headStyle ( ) const

Get the head style.

Returns: Head style

◆ legendIcon()

QwtGraphic QwtPlotArrowMarker::legendIcon	(	int	index,
		const QSizeF &	size
	)		const

overridevirtual

Get the legend icon.

Parameters

[in]	index	Index of the legend entry
[in]	size	Size of the icon

Returns: Legend icon graphic

Reimplemented from QwtPlotItem.

◆ length()

double QwtPlotArrowMarker::length ( ) const

Get the arrow length in pixels.

Returns: Arrow length in pixels

◆ linePen()

const QPen & QwtPlotArrowMarker::linePen ( ) const

Get the arrow line pen.

Returns: Arrow line pen

◆ positionMode()

QwtPlotArrowMarker::PositionMode QwtPlotArrowMarker::positionMode ( ) const

Get the positioning mode.

Returns: Positioning mode

◆ rtti()

int QwtPlotArrowMarker::rtti ( ) const

overridevirtual

Get the runtime type information.

Returns: The RTTI value for QwtPlotArrowMarker (QwtPlotItem::Rtti_PlotArrowMarker)

Reimplemented from QwtPlotItem.

◆ setAngle()

void QwtPlotArrowMarker::setAngle ( double angle )

Set the rotation angle in degrees.

Parameters

[in] angle Rotation angle in degrees

◆ setEndPoint()

void QwtPlotArrowMarker::setEndPoint ( const QPointF & point )

Set the end point in plot coordinates.

Parameters

[in] point End point in plot coordinates

◆ setHeadBrush()

void QwtPlotArrowMarker::setHeadBrush ( const QBrush & brush )

Set the head brush.

Parameters

[in] brush Head brush

◆ setHeadCustomPath()

void QwtPlotArrowMarker::setHeadCustomPath ( const QPainterPath & path )

Set a custom path for head endpoint.

Parameters

[in] path Custom QPainterPath for head

◆ setHeadPen()

void QwtPlotArrowMarker::setHeadPen ( const QPen & pen )

Set the head pen.

Parameters

[in] pen Head pen

◆ setHeadSize() [1/2]

void QwtPlotArrowMarker::setHeadSize ( const QSizeF & size )

Set the head size in pixels.

Parameters

[in] size Head size in pixels

◆ setHeadSize() [2/2]

void QwtPlotArrowMarker::setHeadSize ( qreal size )

Convenience method to set head size with equal width and height.

Parameters

[in] size Head size (both width and height)

◆ setHeadStyle()

void QwtPlotArrowMarker::setHeadStyle ( EndpointStyle style )

Set the head style.

Parameters

[in] style Head style

◆ setLength()

void QwtPlotArrowMarker::setLength ( double length )

Set the arrow length in pixels.

Parameters

[in] length The arrow length in pixels (must be non-negative)

The arrow length is used when position mode is StartLengthAngle. Invalid values (NaN, Infinity) are rejected with a warning.

◆ setLinePen() [1/2]

void QwtPlotArrowMarker::setLinePen	(	const QColor &	color,
		qreal	width = `1.0`,
		Qt::PenStyle	style = `Qt::SolidLine`
	)

Convenience method to set line color and width.

Parameters

[in]	color	Line color
[in]	width	Line width
[in]	style	Line style

◆ setLinePen() [2/2]

void QwtPlotArrowMarker::setLinePen ( const QPen & pen )

Set the arrow line pen.

Parameters

[in] pen Arrow line pen

◆ setPoints()

void QwtPlotArrowMarker::setPoints	(	const QPointF &	start,
		const QPointF &	end
	)

Set both start and end points in plot coordinates.

Parameters

[in]	start	Start point in plot coordinates
[in]	end	End point in plot coordinates

◆ setPositionMode()

void QwtPlotArrowMarker::setPositionMode ( PositionMode mode )

Set the positioning mode.

Parameters

[in] mode Positioning mode

◆ setStartPoint()

void QwtPlotArrowMarker::setStartPoint ( const QPointF & point )

Set the start point in plot coordinates.

Parameters

[in] point Start point in plot coordinates

◆ setTailBrush()

void QwtPlotArrowMarker::setTailBrush ( const QBrush & brush )

Set the tail brush.

Parameters

[in] brush Tail brush

◆ setTailCustomPath()

void QwtPlotArrowMarker::setTailCustomPath ( const QPainterPath & path )

Set a custom path for tail endpoint.

Parameters

[in] path Custom QPainterPath for tail

◆ setTailPen()

void QwtPlotArrowMarker::setTailPen ( const QPen & pen )

Set the tail pen.

Parameters

[in] pen Tail pen

◆ setTailSize() [1/2]

void QwtPlotArrowMarker::setTailSize ( const QSizeF & size )

Set the tail size in pixels.

Parameters

[in] size Tail size in pixels

◆ setTailSize() [2/2]

void QwtPlotArrowMarker::setTailSize ( qreal size )

Convenience method to set tail size with equal width and height.

Parameters

[in] size Tail size (both width and height)

◆ setTailStyle()

void QwtPlotArrowMarker::setTailStyle ( EndpointStyle style )

Set the tail style.

Parameters

[in] style Tail style

◆ startPoint()

QPointF QwtPlotArrowMarker::startPoint ( ) const

Get the start point of the arrow.

Returns: The start point in plot coordinates

◆ tailBrush()

const QBrush & QwtPlotArrowMarker::tailBrush ( ) const

Get the tail brush.

Returns: Tail brush

◆ tailCustomPath()

QPainterPath QwtPlotArrowMarker::tailCustomPath ( ) const

Get the custom tail path.

Returns: Custom tail path

◆ tailPen()

const QPen & QwtPlotArrowMarker::tailPen ( ) const

Get the tail pen.

Returns: Tail pen

◆ tailSize()

QSizeF QwtPlotArrowMarker::tailSize ( ) const

Get the tail size in pixels.

Returns: Tail size in pixels

◆ tailStyle()

QwtPlotArrowMarker::EndpointStyle QwtPlotArrowMarker::tailStyle ( ) const

Get the tail style.

Returns: Tail style

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

/home/runner/work/QWT/QWT/src/plot/qwt_plot_arrowmarker.h
/home/runner/work/QWT/QWT/src/plot/qwt_plot_arrowmarker.cpp

Classes

Public Types

Public Member Functions

Protected Member Functions

Detailed Description

Member Enumeration Documentation

◆ EndpointStyle

◆ PositionMode

Constructor & Destructor Documentation

◆ QwtPlotArrowMarker()

Member Function Documentation

◆ angle()

◆ boundingRect()

◆ draw()

◆ drawCachedEndpoint()

◆ endPoint()

◆ headBrush()

◆ headCustomPath()

◆ headPen()

◆ headSize()

◆ headStyle()

◆ legendIcon()

◆ length()

◆ linePen()

◆ positionMode()

◆ rtti()

◆ setAngle()

◆ setEndPoint()

◆ setHeadBrush()

◆ setHeadCustomPath()

◆ setHeadPen()

◆ setHeadSize() [1/2]

◆ setHeadSize() [2/2]

◆ setHeadStyle()

◆ setLength()

◆ setLinePen() [1/2]

◆ setLinePen() [2/2]

◆ setPoints()

◆ setPositionMode()

◆ setStartPoint()

◆ setTailBrush()

◆ setTailCustomPath()

◆ setTailPen()

◆ setTailSize() [1/2]

◆ setTailSize() [2/2]

◆ setTailStyle()

◆ startPoint()

◆ tailBrush()

◆ tailCustomPath()

◆ tailPen()

◆ tailSize()

◆ tailStyle()