A plot item, that represents a series of points. More...

#include <qwt_plot_curve.h>

Inheritance diagram for QwtPlotCurve:

Classes
class	PrivateData

Public Types
enum	CurveStyle { NoCurve = -1 , Lines , Sticks , Steps , Dots , UserCurve = 100 }
	Curve styles. More...

enum	CurveAttribute { Inverted = 0x01 , Fitted = 0x02 }
	Attribute for drawing the curve. More...

enum	LegendAttribute { LegendNoAttribute = 0x00 , LegendShowLine = 0x01 , LegendShowSymbol = 0x02 , LegendShowBrush = 0x04 }
	Attributes how to represent the curve on the legend. More...

enum	PaintAttribute { ClipPolygons = 0x01 , FilterPoints = 0x02 , MinimizeMemory = 0x04 , ImageBuffer = 0x08 , FilterPointsAggressive = 0x10 , FilterPointsPixel = 0x20 , FilterPointsLTTB = 0x40 }
	Attributes to modify the drawing algorithm. 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
	QwtPlotCurve (const QString &title=QString())

	QwtPlotCurve (const QwtText &title)
	Constructor with QwtText title.

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

void	attach (QwtPlot *plot) override
	Attach the curve to a plot.

void	setPaintAttribute (PaintAttribute, bool on=true)
	Set paint attribute.

bool	testPaintAttribute (PaintAttribute) const
	Test paint attribute.

void	setLegendAttribute (LegendAttribute, bool on=true)
	Set legend attribute.

bool	testLegendAttribute (LegendAttribute) const
	Test legend attribute.

void	setLegendAttributes (LegendAttributes)
	Set legend attributes.

LegendAttributes	legendAttributes () const
	Get legend attributes.

void	setRawSamples (const double xData, const double yData, int size)
	Initialize data by pointing to memory blocks not managed by QwtPlotCurve (double)

void	setRawSamples (const float xData, const float yData, int size)
	Initialize data by pointing to memory blocks not managed by QwtPlotCurve (float)

void	setRawSamples (const double *yData, int size)
	Initialize data by pointing to a memory block not managed by QwtPlotCurve (double, y-axis only)

void	setRawSamples (const float *yData, int size)
	Initialize data by pointing to a memory block not managed by QwtPlotCurve (float, y-axis only)

void	setSamples (const double xData, const double yData, int size)
	Set data by copying x- and y-values from specified memory blocks (double)

void	setSamples (const float xData, const float yData, int size)
	Set data by copying x- and y-values from specified memory blocks (float)

void	setSamples (const double *yData, int size)
	Set data by copying y-values from a specified memory block (double)

void	setSamples (const float *yData, int size)
	Set data by copying y-values from a specified memory block (float)

void	setSamples (const QVector< double > &yData)
	Initialize data with an array of y values (explicitly shared, double)

void	setSamples (const QVector< float > &yData)
	Initialize data with an array of y values (explicitly shared, float)

void	setSamples (const QVector< double > &xData, const QVector< double > &yData)
	Initialize data with x- and y-arrays (explicitly shared, double)

void	setSamples (const QVector< float > &xData, const QVector< float > &yData)
	Initialize data with x- and y-arrays (explicitly shared, float)

void	setSamples (QVector< double > &&xData, QVector< double > &&yData)
	Initialize data with x- and y-arrays (rvalue, double)

void	setSamples (QVector< float > &&xData, QVector< float > &&yData)
	Initialize data with x- and y-arrays (rvalue, float)

void	setSamples (QVector< QPointF > &&)
	Initialize data with an array of points (rvalue)

void	setSamples (const QVector< QPointF > &)
	Initialize data with an array of points.

void	setSamples (QwtSeriesData< QPointF > *)
	Assign a series of points.

virtual int	closestPoint (const QPointF &pos, double *dist=nullptr) const
	Find the closest curve point for a specific position.

double	minXValue () const
	boundingRect().left()

double	maxXValue () const
	boundingRect().right()

double	minYValue () const
	boundingRect().top()

double	maxYValue () const
	boundingRect().bottom()

void	setCurveAttribute (CurveAttribute, bool on=true)
	Set curve attribute.

bool	testCurveAttribute (CurveAttribute) const
	Test curve attribute.

void	setPen (const QColor &, qreal width=0.0, Qt::PenStyle=Qt::SolidLine)
	Build and assign a pen.

void	setPen (const QPen &)
	Assign a pen.

const QPen &	pen () const
	Get the pen used to draw the lines.

void	setBrush (const QBrush &)
	Assign a brush.

const QBrush &	brush () const
	Get the brush used to fill the area between lines and the baseline.

void	setBaseline (double)
	Set the value of the baseline.

double	baseline () const
	Get the baseline value.

void	setStyle (CurveStyle style)
	Set the curve's drawing style.

CurveStyle	style () const
	Get the curve's drawing style.

void	setSymbol (QwtSymbol *)
	Assign a symbol.

const QwtSymbol *	symbol () const
	Get the current symbol.

void	setCurveFitter (QwtCurveFitter *)
	Assign a curve fitter.

QwtCurveFitter *	curveFitter () const
	Get the curve fitter.

virtual void	drawSeries (QPainter *, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect, int from, int to) const override
	Draw an interval of the curve.

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

Public Member Functions inherited from QwtPlotSeriesItem
	QwtPlotSeriesItem (const QString &title=QString())

	QwtPlotSeriesItem (const QwtText &title)
	Constructor.

void	setOrientation (Qt::Orientation)
	Set the orientation of the item.

Qt::Orientation	orientation () const
	Get the orientation of the plot item.

virtual void	draw (QPainter *, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect) const override
	Draw the complete series.

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

virtual void	updateScaleDiv (const QwtScaleDiv &, const QwtScaleDiv &) override
	Update the scale divisions.

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.

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	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.

Public Member Functions inherited from QwtSeriesStore< QPointF >
void	setData (QwtSeriesData< QPointF > *series)

QwtSeriesData< QPointF > *	data ()

const QwtSeriesData< QPointF > *	data () const

QPointF	sample (size_t index) const

virtual size_t	dataSize () const override

virtual QRectF	dataRect () const override

virtual void	setRectOfInterest (const QRectF &rect) override
	Set a the "rectangle of interest" for the stored series.

QwtSeriesData< QPointF > *	swapData (QwtSeriesData< QPointF > *series)

Protected Member Functions
void	init ()
	Initialize the curve.

virtual void	drawCurve (QPainter *, int style, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect, int from, int to) const
	Draw the curve.

virtual void	drawSymbols (QPainter *, const QwtSymbol &, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect, int from, int to) const
	Draw symbols.

virtual void	drawLines (QPainter *, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect, int from, int to) const
	Draw lines.

virtual void	drawSticks (QPainter *, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect, int from, int to) const
	Draw sticks.

virtual void	drawDots (QPainter *, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect, int from, int to) const
	Draw dots.

virtual void	drawSteps (QPainter *, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect, int from, int to) const
	Draw steps.

virtual void	fillCurve (QPainter *, const QwtScaleMap &, const QwtScaleMap &, const QRectF &canvasRect, QPolygonF &) const
	Fill the curve.

void	closePolyline (QPainter *, const QwtScaleMap &, const QwtScaleMap &, QPolygonF &) const
	Close the polyline.

Protected Member Functions inherited from QwtPlotSeriesItem
virtual void	dataChanged () override
	dataChanged() indicates, that the series has been changed.

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

Detailed Description

A plot item, that represents a series of points.

A curve is the representation of a series of points in the x-y plane. It supports different display styles, interpolation ( f.e. spline ) and symbols.

Usage

a) Assign curve properties: When a curve is created, it is configured to draw black solid lines with in QwtPlotCurve::Lines style and no symbols. You can change this by calling setPen(), setStyle() and setSymbol().
b) Connect/Assign data.: QwtPlotCurve gets its points using a QwtSeriesData object offering a bridge to the real storage of the points ( like QAbstractItemModel ). There are several convenience classes derived from QwtSeriesData, that also store the points inside ( like QStandardItemModel ). QwtPlotCurve also offers a couple of variations of setSamples(), that build QwtSeriesData objects from arrays internally.
c) Attach the curve to a plot: See QwtPlotItem::attach()

Example:: see examples/bode

See also: QwtPointSeriesData, QwtSymbol, QwtScaleMap

Member Enumeration Documentation

◆ CurveAttribute

enum QwtPlotCurve::CurveAttribute

Attribute for drawing the curve.

See also: setCurveAttribute(), testCurveAttribute(), curveFitter()

Enumerator

Inverted

For QwtPlotCurve::Steps only. Draws a step function from the right to the left.

Fitted

Only in combination with QwtPlotCurve::Lines A QwtCurveFitter tries to interpolate/smooth the curve, before it is painted.

Note: Curve fitting requires temporary memory for calculating coefficients and additional points. If painting in QwtPlotCurve::Fitted mode is slow it might be better to fit the points, before they are passed to QwtPlotCurve.

◆ CurveStyle

enum QwtPlotCurve::CurveStyle

Curve styles.

See also: setStyle(), style()

Enumerator
NoCurve	Don't draw a curve. Note: This doesn't affect the symbols.
Lines	Connect the points with straight lines. The lines might be interpolated depending on the 'Fitted' attribute. Curve fitting can be configured using setCurveFitter().
Sticks	Draw vertical or horizontal sticks ( depending on the orientation() ) from a baseline which is defined by setBaseline().
Steps	Connect the points with a step function. The step function is drawn from the left to the right or vice versa, depending on the QwtPlotCurve::Inverted attribute.
Dots	Draw dots at the locations of the data points. Note: This is different from a dotted line (see setPen()), and faster as a curve in QwtPlotCurve::NoStyle style and a symbol painting a point.
UserCurve	Styles >= QwtPlotCurve::UserCurve are reserved for derived classes of QwtPlotCurve that overload drawCurve() with additional application specific curve types.

◆ LegendAttribute

enum QwtPlotCurve::LegendAttribute

Attributes how to represent the curve on the legend.

See also: setLegendAttribute(), testLegendAttribute(), QwtPlotItem::legendData(), legendIcon()

Enumerator
LegendNoAttribute	QwtPlotCurve tries to find a color representing the curve and paints a rectangle with it.
LegendShowLine	If the style() is not QwtPlotCurve::NoCurve a line is painted with the curve pen().
LegendShowSymbol	If the curve has a valid symbol it is painted.
LegendShowBrush	If the curve has a brush a rectangle filled with the curve brush() is painted.

◆ PaintAttribute

enum QwtPlotCurve::PaintAttribute

Attributes to modify the drawing algorithm.

The default setting enables ClipPolygons | FilterPointsLTTB

See also: setPaintAttribute(), testPaintAttribute()

Enumerator
ClipPolygons	Clip polygons before painting them. In situations, where points are far outside the visible area (f.e when zooming deep) this might be a substantial improvement for the painting performance
FilterPoints	Tries to reduce the data that has to be painted, by sorting out duplicates, or paintings outside the visible area. Might have a notable impact on curves with many close points. Only a couple of very basic filtering algorithms are implemented.
MinimizeMemory	Minimize memory usage that is temporarily needed for the translated points, before they get painted. This might slow down the performance of painting
ImageBuffer	Render the points to a temporary image and paint the image. This is a very special optimization for Dots style, when having a huge amount of points. With a reasonable number of points QPainter::drawPoints() will be faster.
FilterPointsAggressive	More aggressive point filtering trying to filter out intermediate points, accepting minor visual differences. Has only an effect, when drawing the curve to a paint device in integer coordinates ( f.e. all widgets on screen ) using the fact, that consecutive points are often mapped to the same x or y coordinate. Each chunk of samples mapped to the same coordinate can be reduced to 4 points ( first, min, max last ). In the worst case the polygon to be rendered will be 4 times the width of the plot canvas. The algorithm is very fast and effective for huge datasets, and can be used inside a replot cycle. Note Implemented for QwtPlotCurve::Lines only As this algo replaces many small lines by a long one a nasty bug of the raster paint engine ( Qt 4.8, Qt 5.1 - 5.3 ) becomes more dominant. For these versions the bug can be worked around by enabling the QwtPainter::polylineSplitting() mode.
FilterPointsPixel	Pixel-column based downsampling for extreme performance. Allocates a bin array indexed by pixel column and stores first/min/max/last Y per column. Each column produces at most 4 points. Combined with binary-search visible range for monotonic X data. Output size: ~4 * canvasWidth points regardless of input size. This is the fastest algorithm for datasets exceeding 100k points. Note Implemented for QwtPlotCurve::Lines only Overrides FilterPointsAggressive when both are set
FilterPointsLTTB	MinMax bucket downsampling (simplified LTTB variant). Divides the visible data range into N equal-count buckets and keeps the min-Y and max-Y point from each bucket. N is auto-calculated as 2 * canvasWidth. Output size: ~2 * N points. O(n) time complexity. Preserves visual shape better than FilterPointsPixel for data with uneven X distribution. Note Implemented for QwtPlotCurve::Lines only Overrides FilterPointsAggressive when both are set

Constructor & Destructor Documentation

◆ QwtPlotCurve()

QwtPlotCurve::QwtPlotCurve ( const QwtText & title )

explicit

Constructor with QwtText title.

Parameters

[in] title Title of the curve

Constructor with QString title

Parameters

[in] title Title of the curve

Destructor

Member Function Documentation

◆ attach()

void QwtPlotCurve::attach ( QwtPlot * plot )

overridevirtual

Attach the curve to a plot.

If the pen has not been explicitly set by the user via setPen(), the curve automatically receives a color from the plot's color cycle.

Parameters

plot	Plot to attach to (nullptr to detach)

See also: QwtPlot::nextColorForItem(), QwtPlot::setColorCycle()

Reimplemented from QwtPlotItem.

◆ baseline()

double QwtPlotCurve::baseline ( ) const

Get the baseline value.

Returns: Value of the baseline

See also: setBaseline()

◆ brush()

const QBrush & QwtPlotCurve::brush ( ) const

Get the brush used to fill the area between lines and the baseline.

Returns: Brush used to fill the area between lines and the baseline

See also: setBrush(), setBaseline(), baseline()

◆ closePolyline()

void QwtPlotCurve::closePolyline	(	QPainter *	painter,
		const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap,
		QPolygonF &	polygon
	)		const

protected

Close the polyline.

Complete a polygon to be a closed polygon including the area between the original polygon and the baseline.

Parameters

[in]	painter	Painter
[in]	xMap	X map
[in]	yMap	Y map
[in,out]	polygon	Polygon to be completed

◆ closestPoint()

int QwtPlotCurve::closestPoint	(	const QPointF &	pos,
		double *	dist = `nullptr`
	)		const

virtual

Find the closest curve point for a specific position.

Parameters

[in]	pos	Position where to look for the closest curve point
[out]	dist	If dist != nullptr, returns the distance between the position and the closest curve point

Returns: Index of the closest curve point, or -1 if none can be found (e.g. when the curve has no points)

Note: closestPoint() implements a dumb algorithm that iterates over all points

◆ curveFitter()

QwtCurveFitter * QwtPlotCurve::curveFitter ( ) const

Get the curve fitter.

Returns: Curve fitter, or nullptr if curve fitting is disabled

See also: setCurveFitter(), Fitted

◆ drawCurve()

void QwtPlotCurve::drawCurve	(	QPainter *	painter,
		int	style,
		const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap,
		const QRectF &	canvasRect,
		int	from,
		int	to
	)		const

protectedvirtual

Draw the curve.

Draw the line part (without symbols) of a curve interval.

Parameters

[in]	painter	Painter
[in]	style	Curve style, see QwtPlotCurve::CurveStyle
[in]	xMap	X map
[in]	yMap	Y map
[in]	canvasRect	Contents rectangle of the canvas
[in]	from	Index of the first point to be painted
[in]	to	Index of the last point to be painted

See also: draw(), drawDots(), drawLines(), drawSteps(), drawSticks()

◆ drawDots()

void QwtPlotCurve::drawDots	(	QPainter *	painter,
		const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap,
		const QRectF &	canvasRect,
		int	from,
		int	to
	)		const

protectedvirtual

Draw dots.

Parameters

[in]	painter	Painter
[in]	xMap	X map
[in]	yMap	Y map
[in]	canvasRect	Contents rectangle of the canvas
[in]	from	Index of the first point to be painted
[in]	to	Index of the last point to be painted

See also: draw(), drawCurve(), drawSticks(), drawLines(), drawSteps()

◆ drawLines()

void QwtPlotCurve::drawLines	(	QPainter *	painter,
		const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap,
		const QRectF &	canvasRect,
		int	from,
		int	to
	)		const

protectedvirtual

Draw lines.

If the CurveAttribute Fitted is enabled a QwtCurveFitter tries to interpolate/smooth the curve, before it is painted.

Parameters

[in]	painter	Painter
[in]	xMap	X map
[in]	yMap	Y map
[in]	canvasRect	Contents rectangle of the canvas
[in]	from	Index of the first point to be painted
[in]	to	Index of the last point to be painted

See also: setCurveAttribute(), setCurveFitter(), draw(), drawLines(), drawDots(), drawSteps(), drawSticks()

◆ drawSeries()

void QwtPlotCurve::drawSeries	(	QPainter *	painter,
		const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap,
		const QRectF &	canvasRect,
		int	from,
		int	to
	)		const

overridevirtual

Draw an interval of the curve.

Parameters

[in]	painter	Painter
[in]	xMap	Maps x-values into pixel coordinates
[in]	yMap	Maps y-values into pixel coordinates
[in]	canvasRect	Contents rectangle of the canvas
[in]	from	Index of the first point to be painted
[in]	to	Index of the last point to be painted. If to < 0 the curve will be painted to its last point.

See also: drawCurve(), drawSymbols()

Implements QwtPlotSeriesItem.

◆ drawSteps()

void QwtPlotCurve::drawSteps	(	QPainter *	painter,
		const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap,
		const QRectF &	canvasRect,
		int	from,
		int	to
	)		const

protectedvirtual

Draw steps.

Draw step function.

The direction of the steps depends on Inverted attribute.

Parameters

[in]	painter	Painter
[in]	xMap	X map
[in]	yMap	Y map
[in]	canvasRect	Contents rectangle of the canvas
[in]	from	Index of the first point to be painted
[in]	to	Index of the last point to be painted

See also: CurveAttribute, setCurveAttribute(), draw(), drawCurve(), drawDots(), drawLines(), drawSticks()

◆ drawSticks()

void QwtPlotCurve::drawSticks	(	QPainter *	painter,
		const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap,
		const QRectF &	canvasRect,
		int	from,
		int	to
	)		const

protectedvirtual

Draw sticks.

Parameters

[in]	painter	Painter
[in]	xMap	X map
[in]	yMap	Y map
[in]	canvasRect	Contents rectangle of the canvas
[in]	from	Index of the first point to be painted
[in]	to	Index of the last point to be painted

See also: draw(), drawCurve(), drawDots(), drawLines(), drawSteps()

◆ drawSymbols()

void QwtPlotCurve::drawSymbols	(	QPainter *	painter,
		const QwtSymbol &	symbol,
		const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap,
		const QRectF &	canvasRect,
		int	from,
		int	to
	)		const

protectedvirtual

Draw symbols.

Parameters

[in]	painter	Painter
[in]	symbol	Curve symbol
[in]	xMap	X map
[in]	yMap	Y map
[in]	canvasRect	Contents rectangle of the canvas
[in]	from	Index of the first point to be painted
[in]	to	Index of the last point to be painted

See also: setSymbol(), drawSeries(), drawCurve()

◆ fillCurve()

void QwtPlotCurve::fillCurve	(	QPainter *	painter,
		const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap,
		const QRectF &	canvasRect,
		QPolygonF &	polygon
	)		const

protectedvirtual

Fill the curve.

Fill the area between the curve and the baseline with the curve brush.

Parameters

[in]	painter	Painter
[in]	xMap	X map
[in]	yMap	Y map
[in]	canvasRect	Contents rectangle of the canvas
[in,out]	polygon	Polygon - will be modified

See also: setBrush(), setBaseline(), setStyle()

◆ init()

void QwtPlotCurve::init ( )

protected

Initialize the curve.

Initialize internal members.

Sets default attributes and creates internal data structures.

◆ legendAttributes()

QwtPlotCurve::LegendAttributes QwtPlotCurve::legendAttributes ( ) const

Get legend attributes.

Returns: Attributes for drawing the legend icon

See also: setLegendAttributes(), testLegendAttribute()

◆ legendIcon()

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

overridevirtual

Get the icon representing the curve on the legend.

Parameters

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

Returns: Icon representing the curve on the legend

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

Reimplemented from QwtPlotItem.

◆ pen()

const QPen & QwtPlotCurve::pen ( ) const

Get the pen used to draw the lines.

Returns: Pen used to draw the lines

See also: setPen(), brush()

◆ rtti()

int QwtPlotCurve::rtti ( ) const

overridevirtual

Get the runtime type information.

Returns: QwtPlotItem::Rtti_PlotCurve

Reimplemented from QwtPlotItem.

◆ setBaseline()

void QwtPlotCurve::setBaseline ( double value )

Set the value of the baseline.

The baseline is needed for filling the curve with a brush or the Sticks drawing style. The interpretation of the baseline depends on the orientation(). With Qt::Vertical, the baseline is interpreted as a horizontal line at y = baseline(), with Qt::Horizontal, it is interpreted as a vertical line at x = baseline(). The default value is 0.0.

Parameters

[in] value Value of the baseline

See also: baseline(), setBrush(), setStyle(), QwtPlotAbstractSeriesItem::orientation()

◆ setBrush()

void QwtPlotCurve::setBrush ( const QBrush & brush )

Assign a brush.

In case of brush.style() != QBrush::NoBrush and style() != QwtPlotCurve::Sticks, the area between the curve and the baseline will be filled. In case !brush.color().isValid() the area will be filled by pen.color(). The fill algorithm simply connects the first and the last curve point to the baseline. So the curve data has to be sorted (ascending or descending).

Parameters

[in] brush New brush

See also: brush(), setBaseline(), baseline()

◆ setCurveAttribute()

void QwtPlotCurve::setCurveAttribute	(	CurveAttribute	attribute,
		bool	on = `true`
	)

Set curve attribute.

Parameters

[in]	attribute	Curve attribute
[in]	on	On/Off

See also: testCurveAttribute(), setCurveFitter()

◆ setCurveFitter()

void QwtPlotCurve::setCurveFitter ( QwtCurveFitter * curveFitter )

Assign a curve fitter.

The curve fitter "smooths" the curve points, when the Fitted CurveAttribute is set. setCurveFitter(nullptr) also disables curve fitting. The curve fitter operates on the translated points (= widget coordinates) to be functional for logarithmic scales. Obviously this is less performant for fitting algorithms, that reduce the number of points. For situations, where curve fitting is used to improve the performance of painting huge series of points it might be better to execute the fitter on the curve points once and to cache the result in the QwtSeriesData object.

Parameters

[in] curveFitter Curve fitter

See also: Fitted

◆ setLegendAttribute()

void QwtPlotCurve::setLegendAttribute	(	LegendAttribute	attribute,
		bool	on = `true`
	)

Set legend attribute.

Parameters

[in]	attribute	Legend attribute
[in]	on	On/Off

See also: testLegendAttribute(), legendIcon()

◆ setLegendAttributes()

void QwtPlotCurve::setLegendAttributes ( LegendAttributes attributes )

Set legend attributes.

Parameters

[in] attributes Legend attributes

See also: setLegendAttribute(), legendIcon()

◆ setPaintAttribute()

void QwtPlotCurve::setPaintAttribute	(	PaintAttribute	attribute,
		bool	on = `true`
	)

Set paint attribute.

Parameters

[in]	attribute	Paint attribute
[in]	on	On/Off

See also: testPaintAttribute()

◆ setPen() [1/2]

void QwtPlotCurve::setPen	(	const QColor &	color,
		qreal	width = `0.0`,
		Qt::PenStyle	style = `Qt::SolidLine`
	)

Build and assign a pen.

In Qt5 the default pen width is 1.0 (0.0 in Qt4) which makes it non cosmetic (see QPen::isCosmetic()). This method has been introduced to hide this incompatibility.

Parameters

[in]	color	Pen color
[in]	width	Pen width
[in]	style	Pen style

See also: pen(), brush()

◆ setPen() [2/2]

void QwtPlotCurve::setPen ( const QPen & pen )

Assign a pen.

Parameters

[in] pen New pen

See also: pen(), brush()

◆ setRawSamples() [1/4]

void QwtPlotCurve::setRawSamples	(	const double *	xData,
		const double *	yData,
		int	size
	)

Initialize data by pointing to memory blocks not managed by QwtPlotCurve (double)

setRawSamples is provided for efficiency. It is important to keep the pointers during the lifetime of the underlying QwtCPointerData class.

Parameters

[in]	xData	Pointer to x data
[in]	yData	Pointer to y data
[in]	size	Size of x and y

See also: QwtCPointerData

◆ setRawSamples() [2/4]

void QwtPlotCurve::setRawSamples	(	const double *	yData,
		int	size
	)

Initialize data by pointing to a memory block not managed by QwtPlotCurve (double, y-axis only)

The memory contains the y coordinates, while the index is interpreted as x coordinate. setRawSamples() is provided for efficiency. It is important to keep the pointers during the lifetime of the underlying QwtCPointerValueData class.

Parameters

[in]	yData	Pointer to y data
[in]	size	Size of y data

See also: QwtCPointerData

◆ setRawSamples() [3/4]

void QwtPlotCurve::setRawSamples	(	const float *	xData,
		const float *	yData,
		int	size
	)

Initialize data by pointing to memory blocks not managed by QwtPlotCurve (float)

setRawSamples is provided for efficiency. It is important to keep the pointers during the lifetime of the underlying QwtCPointerData class.

Parameters

[in]	xData	Pointer to x data
[in]	yData	Pointer to y data
[in]	size	Size of x and y

See also: QwtCPointerData

◆ setRawSamples() [4/4]

void QwtPlotCurve::setRawSamples	(	const float *	yData,
		int	size
	)

Initialize data by pointing to a memory block not managed by QwtPlotCurve (float, y-axis only)

The memory contains the y coordinates, while the index is interpreted as x coordinate. setRawSamples() is provided for efficiency. It is important to keep the pointers during the lifetime of the underlying QwtCPointerValueData class.

Parameters

[in]	yData	Pointer to y data
[in]	size	Size of y data

See also: QwtCPointerData

◆ setSamples() [1/13]

void QwtPlotCurve::setSamples	(	const double *	xData,
		const double *	yData,
		int	size
	)

Set data by copying x- and y-values from specified memory blocks (double)

Contrary to setRawSamples(), this function makes a 'deep copy' of the data.

Parameters

[in]	xData	Pointer to x values
[in]	yData	Pointer to y values
[in]	size	Size of xData and yData

See also: QwtPointArrayData

◆ setSamples() [2/13]

void QwtPlotCurve::setSamples	(	const double *	yData,
		int	size
	)

Set data by copying y-values from a specified memory block (double)

The memory contains the y coordinates, while the index is interpreted as x coordinate.

Parameters

[in]	yData	Y data
[in]	size	Size of yData

See also: QwtValuePointData

◆ setSamples() [3/13]

void QwtPlotCurve::setSamples	(	const float *	xData,
		const float *	yData,
		int	size
	)

Set data by copying x- and y-values from specified memory blocks (float)

Contrary to setRawSamples(), this function makes a 'deep copy' of the data.

Parameters

[in]	xData	Pointer to x values
[in]	yData	Pointer to y values
[in]	size	Size of xData and yData

See also: QwtPointArrayData

◆ setSamples() [4/13]

void QwtPlotCurve::setSamples	(	const float *	yData,
		int	size
	)

Set data by copying y-values from a specified memory block (float)

The vector contains the y coordinates, while the index is interpreted as x coordinate.

Parameters

[in]	yData	Y data
[in]	size	Size of yData

See also: QwtValuePointData

◆ setSamples() [5/13]

void QwtPlotCurve::setSamples	(	const QVector< double > &	xData,
		const QVector< double > &	yData
	)

Initialize data with x- and y-arrays (explicitly shared, double)

Parameters

[in]	xData	X data
[in]	yData	Y data

See also: QwtPointArrayData

◆ setSamples() [6/13]

void QwtPlotCurve::setSamples ( const QVector< double > & yData )

Initialize data with an array of y values (explicitly shared, double)

The vector contains the y coordinates, while the index is the x coordinate.

Parameters

[in] yData Y data

See also: QwtValuePointData

◆ setSamples() [7/13]

void QwtPlotCurve::setSamples	(	const QVector< float > &	xData,
		const QVector< float > &	yData
	)

Initialize data with x- and y-arrays (explicitly shared, float)

Parameters

[in]	xData	X data
[in]	yData	Y data

See also: QwtPointArrayData

◆ setSamples() [8/13]

void QwtPlotCurve::setSamples ( const QVector< float > & yData )

Initialize data with an array of y values (explicitly shared, float)

The vector contains the y coordinates, while the index is the x coordinate.

Parameters

[in] yData Y data

See also: QwtValuePointData

◆ setSamples() [9/13]

void QwtPlotCurve::setSamples ( const QVector< QPointF > & samples )

Initialize data with an array of points.

Parameters

[in] samples Vector of points

Note: QVector is implicitly shared; QPolygonF is derived from QVector<QPointF>

◆ setSamples() [10/13]

void QwtPlotCurve::setSamples	(	QVector< double > &&	xData,
		QVector< double > &&	yData
	)

Initialize data with x- and y-arrays (rvalue, double)

Parameters

[in]	xData	X data
[in]	yData	Y data

See also: QwtPointArrayData

◆ setSamples() [11/13]

void QwtPlotCurve::setSamples	(	QVector< float > &&	xData,
		QVector< float > &&	yData
	)

Initialize data with x- and y-arrays (rvalue, float)

Parameters

[in]	xData	X data
[in]	yData	Y data

See also: QwtPointArrayData

◆ setSamples() [12/13]

void QwtPlotCurve::setSamples ( QVector< QPointF > && samples )

Initialize data with an array of points (rvalue)

Parameters

[in] samples Vector of points

Note: QVector is implicitly shared; QPolygonF is derived from QVector<QPointF>

◆ setSamples() [13/13]

void QwtPlotCurve::setSamples ( QwtSeriesData< QPointF > * data )

Assign a series of points.

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

Parameters

[in] data Data

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

◆ setStyle()

void QwtPlotCurve::setStyle ( CurveStyle style )

Set the curve's drawing style.

Parameters

[in] style Curve style

See also: style()

◆ setSymbol()

void QwtPlotCurve::setSymbol ( QwtSymbol * symbol )

Assign a symbol.

The curve will take the ownership of the symbol, hence the previously set symbol will be deleted by setting a new one. If symbol is nullptr no symbol will be drawn.

Parameters

[in] symbol Symbol

See also: symbol()

◆ style()

QwtPlotCurve::CurveStyle QwtPlotCurve::style ( ) const

Get the curve's drawing style.

Returns: Style of the curve

See also: setStyle()

◆ symbol()

const QwtSymbol * QwtPlotCurve::symbol ( ) const

Get the current symbol.

Returns: Current symbol or nullptr when no symbol has been assigned

See also: setSymbol()

◆ testCurveAttribute()

bool QwtPlotCurve::testCurveAttribute ( CurveAttribute attribute ) const

Test curve attribute.

Parameters

[in] attribute Curve attribute

Returns: True if attribute is enabled

See also: setCurveAttribute()

◆ testLegendAttribute()

bool QwtPlotCurve::testLegendAttribute ( LegendAttribute attribute ) const

Test legend attribute.

Parameters

[in] attribute Legend attribute

Returns: True when attribute is enabled

See also: setLegendAttribute()

◆ testPaintAttribute()

bool QwtPlotCurve::testPaintAttribute ( PaintAttribute attribute ) const

Test paint attribute.

Parameters

[in] attribute Paint attribute

Returns: True when attribute is enabled

See also: setPaintAttribute()

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

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

Classes

Public Types

Public Member Functions

Protected Member Functions

Detailed Description

Member Enumeration Documentation

◆ CurveAttribute

◆ CurveStyle

◆ LegendAttribute

◆ PaintAttribute

Constructor & Destructor Documentation

◆ QwtPlotCurve()

Member Function Documentation

◆ attach()

◆ baseline()

◆ brush()

◆ closePolyline()

◆ closestPoint()

◆ curveFitter()

◆ drawCurve()

◆ drawDots()

◆ drawLines()

◆ drawSeries()

◆ drawSteps()

◆ drawSticks()

◆ drawSymbols()

◆ fillCurve()

◆ init()

◆ legendAttributes()

◆ legendIcon()

◆ pen()

◆ rtti()

◆ setBaseline()

◆ setBrush()

◆ setCurveAttribute()

◆ setCurveFitter()

◆ setLegendAttribute()

◆ setLegendAttributes()

◆ setPaintAttribute()

◆ setPen() [1/2]

◆ setPen() [2/2]

◆ setRawSamples() [1/4]

◆ setRawSamples() [2/4]

◆ setRawSamples() [3/4]

◆ setRawSamples() [4/4]

◆ setSamples() [1/13]

◆ setSamples() [2/13]

◆ setSamples() [3/13]

◆ setSamples() [4/13]

◆ setSamples() [5/13]

◆ setSamples() [6/13]

◆ setSamples() [7/13]

◆ setSamples() [8/13]

◆ setSamples() [9/13]

◆ setSamples() [10/13]

◆ setSamples() [11/13]

◆ setSamples() [12/13]

◆ setSamples() [13/13]

◆ setStyle()

◆ setSymbol()

◆ style()

◆ symbol()

◆ testCurveAttribute()

◆ testLegendAttribute()

◆ testPaintAttribute()