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

#include <qwt_plot_curve.h>

类 QwtPlotCurve 继承关系图:

类
class	PrivateData

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

enum	CurveAttribute { Inverted = 0x01 , Fitted = 0x02 , BreakAtNan = 0x04 }
	Attribute for drawing the curve 更多...

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

enum	PaintAttribute { ClipPolygons = 0x01 , FilterPoints = 0x02 , MinimizeMemory = 0x04 , ImageBuffer = 0x08 , FilterPointsAggressive = 0x10 , FilterPointsPixel = 0x20 , FilterPointsLTTB = 0x40 , FilterPointsMinMaxLTTB = 0x80 , FilterPointsAdaptive = 0x100 }
	Attributes to modify the drawing algorithm 更多...

enum	SmoothAlgorithm { NoSmoothing = 0 , GaussianSmoothing , SavitzkyGolaySmoothing }
	Algorithm for smoothing the rendered polyline 更多...

Public 类型继承自 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 更多...

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

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

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

Public 成员函数
	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

void	setSmoothAlgorithm (SmoothAlgorithm)
	Set the render smoothing algorithm

SmoothAlgorithm	smoothAlgorithm () const
	Get the render smoothing algorithm

void	setSmoothWindow (int numPoints)
	Set the window of the render smoothing algorithms

int	smoothWindow () const
	Get the window of the render smoothing algorithms

void	setSmoothPolynomialOrder (int order)
	Set the polynomial order of SavitzkyGolaySmoothing

int	smoothPolynomialOrder () const
	Get the polynomial order of SavitzkyGolaySmoothing

void	setSmoothPreserveThreshold (double threshold)
	Set the feature preservation threshold of the render smoothing

double	smoothPreserveThreshold () const
	Get the feature preservation threshold of the render smoothing

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 成员函数继承自 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 成员函数继承自 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 成员函数继承自 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 成员函数
virtual void	dataChanged () override
	Invalidate data dependent caches when the series has been changed

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 成员函数继承自 QwtPlotItem
QwtGraphic	defaultIcon (const QBrush &, const QSizeF &) const
	Create a default icon

详细描述

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

参见: QwtPointSeriesData, QwtSymbol, QwtScaleMap

成员枚举类型说明

◆ CurveAttribute

enum QwtPlotCurve::CurveAttribute

Attribute for drawing the curve

参见: setCurveAttribute(), testCurveAttribute(), curveFitter()

枚举值

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.

注解: 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.

BreakAtNan

For Lines and Steps style only. Samples with NaN/Inf coordinates mark gaps: instead of connecting the neighboring finite samples with a bridging line, every run of consecutive finite samples is rendered as an independent polyline and gaps stay blank.

Without this attribute gaps are bridged, what is the default behavior of all paint attribute filtering modes.

Each run is smoothed, fitted, clipped and filled on its own, so neither the smoothing kernel nor the fill area crosses a gap. Downsampling budgets also apply per run - short runs fall back to simpler filtering algorithms.

The Dots and Sticks styles are not affected, as they draw per sample and skip NaN/Inf samples anyway.

注解: The finite sample runs are cached and recomputed whenever the series data is set ( setSamples()/setData() ).

Example:

QwtPlotCurve* curve = new QwtPlotCurve();
curve->setSamples( x, y );            // y contains qQNaN() gaps
curve->setCurveAttribute( QwtPlotCurve::BreakAtNan, true );
curve->attach( plot );

◆ CurveStyle

enum QwtPlotCurve::CurveStyle

Curve styles

参见: setStyle(), style()

枚举值
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

参见: setLegendAttribute(), testLegendAttribute(), QwtPlotItem::legendData(), legendIcon()

枚举值
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

参见: setPaintAttribute(), testPaintAttribute()

枚举值
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. 弃用: Superseded by FilterPointsAdaptive: reducing each chunk to integer first/min/max/last quadruples produces 1px staircase artifacts for oversampled smooth curves. Kept for compatibility for at least one version cycle. 注解 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. Columns holding more than one point are emitted as a cluster in the layout of the adaptive sampling of QCustomPlot: min and max at fixed sub pixel positions ( +0.25 / +0.75 ), so that the vertical stroke of a column stays inside its pixel, plus the real first/last point only where the neighbor column is empty or holds a single point. Output size: ~4 * canvasWidth points regardless of input size. This is the fastest algorithm for datasets exceeding 100k points. 弃用: Superseded by FilterPointsAdaptive: the min/max envelope per pixel column discards the sample order and shape, producing ( milder ) staircase artifacts of the same family as FilterPointsAggressive for oversampled smooth curves. Kept for compatibility for at least one version cycle. 注解 Implemented for QwtPlotCurve::Lines only Overrides FilterPointsAggressive when both are set
FilterPointsLTTB	Largest-Triangle-Three-Buckets (LTTB) downsampling. Divides the visible data range into N equal-count buckets and keeps the sample of each bucket, that forms the largest triangle with the previously selected point and the average of the next bucket. The first and last sample are always kept. N is auto-calculated as 4 * canvasWidth. Output size: ~N points. O(n) time complexity. Preserves the visual shape of the curve ( f.e. narrow peaks ) much better than the MinMax bucket algorithm, at the cost of being slightly slower. 注解 Implemented for QwtPlotCurve::Lines only Overrides FilterPointsAggressive when both are set
FilterPointsMinMaxLTTB	MinMax bucket downsampling. 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 the extremes of each bucket, but may collapse narrow peaks into vertical strokes. This is the algorithm that was behind FilterPointsLTTB up to v7.4.2. 注解 Implemented for QwtPlotCurve::Lines only Overrides FilterPointsAggressive when both are set
FilterPointsAdaptive	Adaptive column reduce downsampling. Single pass O(n) algorithm designed for the display quality of oversampled curves ( f.e. smooth spectra with many samples per peak ), all pixel quantities in device pixels: Density gate: when the visible samples are not denser than 2 points per device pixel column the curve is painted 1:1 without any reduction - zooming in always restores full fidelity. Otherwise the samples are clustered by device pixel column. Inside a cluster the first sample, every sample whose mapped y differs by at least 1 device pixel from the last kept sample and the last sample are kept - in their original order and at their real sub pixel coordinates. Ramps stay ramps: no 1px staircase artifacts like with the min/max envelope per column ( FilterPointsPixel, FilterPointsAggressive ). High frequency noise inside one column falls back to an ordered first/min/max/last quadruple, bounding the output to at most K + 1 points per column ( K = 4 + column span in device pixels ). The deviation from the original curve is bounded by 1 device pixel vertically and one column horizontally. For smooth data the output size is roughly the vertical pixel travel - typically larger than FilterPointsLTTB ( the price of the shape preservation ), but far below the unreduced point count. 注解 Implemented for QwtPlotCurve::Lines only Overrides all other FilterPoints reductions when both are set

◆ SmoothAlgorithm

enum QwtPlotCurve::SmoothAlgorithm

Algorithm for smoothing the rendered polyline

The smoothing is applied to the polyline that has been downsampled and translated to paint coordinates. It targets the pixel level noise of curves with many samples ( f.e. spectra with random jitter ), while the sample data itself is not modified.

In contrast to the Fitted attribute, that interpolates through all points, the smoothing algorithms are low pass filters. Significant features ( peaks, dips ) are restored to their original position and height afterwards, so that the smoothing does not distort the curve, see setSmoothPreserveThreshold().

注解: Implemented for QwtPlotCurve::Lines only

参见: setSmoothAlgorithm(), setSmoothWindow(), setSmoothPolynomialOrder(), setSmoothPreserveThreshold()

枚举值
NoSmoothing	No smoothing ( default )
GaussianSmoothing	Gaussian weighted moving window: strong noise suppression
SavitzkyGolaySmoothing	Savitzky-Golay local polynomial regression: keeps the height and shape of narrow peaks better than GaussianSmoothing

构造及析构函数说明

◆ QwtPlotCurve()

QwtPlotCurve::QwtPlotCurve ( const QwtText & title )

explicit

Constructor with QwtText title

参数

[in] title Title of the curve

Constructor with QString title

参数

[in] title Title of the curve

Destructor

成员函数说明

◆ 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. If an uncustomized symbol (default brush/pen) has been assigned, it is auto-colored to match the curve pen as well.

参数

plot	Plot to attach to (nullptr to detach)

参见: QwtPlot::nextColorForItem(), QwtPlot::setColorCycle(), setSymbol()

重载 QwtPlotItem .

◆ baseline()

double QwtPlotCurve::baseline ( ) const

Get the baseline value

返回: Value of the baseline

参见: setBaseline()

◆ brush()

const QBrush & QwtPlotCurve::brush ( ) const

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

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

参见: 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

参数

[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

参数

[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

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

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

◆ curveFitter()

QwtCurveFitter * QwtPlotCurve::curveFitter ( ) const

Get the curve fitter

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

参见: setCurveFitter(), Fitted

◆ dataChanged()

void QwtPlotCurve::dataChanged ( )

overrideprotectedvirtual

Invalidate data dependent caches when the series has been changed

重载 QwtPlotSeriesItem .

◆ 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

参数

[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

参见: 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

参数

[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

参见: 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.

参数

[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

参见: 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

参数

[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.

参见: drawCurve(), drawSymbols()

实现了 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.

参数

[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

参见: 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

参数

[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

参见: 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

参数

[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

参见: 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

参数

[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

参见: 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

返回: Attributes for drawing the legend icon

参见: setLegendAttributes(), testLegendAttribute()

◆ legendIcon()

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

overridevirtual

Get the icon representing the curve on the legend

参数

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

返回: Icon representing the curve on the legend

参见: QwtPlotItem::setLegendIconSize(), QwtPlotItem::legendData()

重载 QwtPlotItem .

◆ pen()

const QPen & QwtPlotCurve::pen ( ) const

Get the pen used to draw the lines

返回: Pen used to draw the lines

参见: setPen(), brush()

◆ rtti()

int QwtPlotCurve::rtti ( ) const

overridevirtual

Get the runtime type information

返回: QwtPlotItem::Rtti_PlotCurve

重载 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.

参数

[in] value Value of the baseline

参见: 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).

参数

[in] brush New brush

参见: brush(), setBaseline(), baseline()

◆ setCurveAttribute()

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

Set curve attribute

参数

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

参见: 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.

参数

[in] curveFitter Curve fitter

参见: Fitted

◆ setLegendAttribute()

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

Set legend attribute

参数

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

参见: testLegendAttribute(), legendIcon()

◆ setLegendAttributes()

void QwtPlotCurve::setLegendAttributes ( LegendAttributes attributes )

Set legend attributes

参数

[in] attributes Legend attributes

参见: setLegendAttribute(), legendIcon()

◆ setPaintAttribute()

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

Set paint attribute

参数

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

参见: 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.

参数

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

参见: pen(), brush()

◆ setPen() [2/2]

void QwtPlotCurve::setPen ( const QPen & pen )

Assign a pen

参数

[in] pen New pen

参见: 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.

参数

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

参见: 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.

参数

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

参见: 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.

参数

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

参见: 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.

参数

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

参见: 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.

参数

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

参见: 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.

参数

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

参见: 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.

参数

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

参见: 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.

参数

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

参见: 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)

参数

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

参见: 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.

参数

[in] yData Y data

参见: 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)

参数

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

参见: 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.

参数

[in] yData Y data

参见: QwtValuePointData

◆ setSamples() [9/13]

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

Initialize data with an array of points

参数

[in] samples Vector of points

注解: 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)

参数

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

参见: QwtPointArrayData

◆ setSamples() [11/13]

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

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

参数

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

参见: QwtPointArrayData

◆ setSamples() [12/13]

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

Initialize data with an array of points (rvalue)

参数

[in] samples Vector of points

注解: 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.

参数

[in] data Data

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

◆ setSmoothAlgorithm()

void QwtPlotCurve::setSmoothAlgorithm ( SmoothAlgorithm algorithm )

Set the render smoothing algorithm

In combination with QwtPlotCurve::Lines the rendered polyline can be smoothed by a low pass filter, that is applied to the polyline that has been downsampled and translated to paint coordinates.

This is about removing pixel level noise ( f.e. from spectra with random jitter ), while the sample data itself is not modified. In contrast to the Fitted attribute the algorithms do not interpolate through the points.

参数

[in] algorithm Smoothing algorithm

参见: smoothAlgorithm(), setSmoothWindow(), setSmoothPolynomialOrder()

◆ setSmoothPolynomialOrder()

void QwtPlotCurve::setSmoothPolynomialOrder ( int order )

Set the polynomial order of SavitzkyGolaySmoothing

Higher orders keep the shape of narrow peaks better, but reduce the noise suppression. The order is limited to 1 .. smoothWindow() - 2.

The setting has no effect for other smoothing algorithms. The default value is 3.

参数

[in] order Polynomial order

参见: smoothPolynomialOrder(), setSmoothWindow()

◆ setSmoothPreserveThreshold()

void QwtPlotCurve::setSmoothPreserveThreshold ( double threshold )

Set the feature preservation threshold of the render smoothing

A linear low pass filter attenuates features that are narrower than its window ( f.e. the peaks of a spectrum ). To avoid this distortion the smoothing restores the original position and height of all points, that deviate from a wide baseline by more than threshold multiples of the estimated noise level.

Lower values preserve more of the curve ( at the cost of keeping more noise ), higher values preserve only the most significant features. A value <= 0 disables the feature preservation, what results in a pure low pass filter.

The default value is 3.0.

参数

[in] threshold Threshold in multiples of the noise level

参见: smoothPreserveThreshold(), setSmoothAlgorithm()

◆ setSmoothWindow()

void QwtPlotCurve::setSmoothWindow ( int numPoints )

Set the window of the render smoothing algorithms

The window is the number of neighboring polyline points, that contribute to the smoothed position of a point. As the smoothing happens after downsampling, the polyline is usually not much longer than a multiple of the canvas width.

Values < 3 are raised to 3, even values are rounded up to the next odd value. The default value is 9.

参数

[in] numPoints Window size

参见: smoothWindow(), setSmoothAlgorithm()

◆ setStyle()

void QwtPlotCurve::setStyle ( CurveStyle style )

Set the curve's drawing style

参数

[in] style Curve style

参见: 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.

If the curve is already attached and the new symbol is in its default (uncustomized) state, it is auto-colored to match the curve pen, so that a scatter-style curve inherits the color cycle color of its pen.

参数

[in] symbol Symbol

参见: symbol(), attach()

◆ smoothAlgorithm()

QwtPlotCurve::SmoothAlgorithm QwtPlotCurve::smoothAlgorithm ( ) const

Get the render smoothing algorithm

返回: Smoothing algorithm

参见: setSmoothAlgorithm()

◆ smoothPolynomialOrder()

int QwtPlotCurve::smoothPolynomialOrder ( ) const

Get the polynomial order of SavitzkyGolaySmoothing

返回: Polynomial order

参见: setSmoothPolynomialOrder()

◆ smoothPreserveThreshold()

double QwtPlotCurve::smoothPreserveThreshold ( ) const

Get the feature preservation threshold of the render smoothing

返回: Threshold in multiples of the noise level

参见: setSmoothPreserveThreshold()

◆ smoothWindow()

int QwtPlotCurve::smoothWindow ( ) const

Get the window of the render smoothing algorithms

返回: Window size

参见: setSmoothWindow()

◆ style()

QwtPlotCurve::CurveStyle QwtPlotCurve::style ( ) const

Get the curve's drawing style

返回: Style of the curve

参见: setStyle()

◆ symbol()

const QwtSymbol * QwtPlotCurve::symbol ( ) const

Get the current symbol

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

参见: setSymbol()

◆ testCurveAttribute()

bool QwtPlotCurve::testCurveAttribute ( CurveAttribute attribute ) const

Test curve attribute

参数

[in] attribute Curve attribute

返回: True if attribute is enabled

参见: setCurveAttribute()

◆ testLegendAttribute()

bool QwtPlotCurve::testLegendAttribute ( LegendAttribute attribute ) const

Test legend attribute

参数

[in] attribute Legend attribute

返回: True when attribute is enabled

参见: setLegendAttribute()

◆ testPaintAttribute()

bool QwtPlotCurve::testPaintAttribute ( PaintAttribute attribute ) const

Test paint attribute

参数

[in] attribute Paint attribute

返回: True when attribute is enabled

参见: setPaintAttribute()

该类的文档由以下文件生成:

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

类

Public 类型

Public 成员函数

Protected 成员函数

详细描述

成员枚举类型说明

◆ CurveAttribute

◆ CurveStyle

◆ LegendAttribute

◆ PaintAttribute

◆ SmoothAlgorithm

构造及析构函数说明

◆ QwtPlotCurve()

成员函数说明

◆ attach()

◆ baseline()

◆ brush()

◆ closePolyline()

◆ closestPoint()

◆ curveFitter()

◆ dataChanged()

◆ 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]

◆ setSmoothAlgorithm()

◆ setSmoothPolynomialOrder()

◆ setSmoothPreserveThreshold()

◆ setSmoothWindow()

◆ setStyle()

◆ setSymbol()

◆ smoothAlgorithm()

◆ smoothPolynomialOrder()

◆ smoothPreserveThreshold()

◆ smoothWindow()

◆ style()

◆ symbol()

◆ testCurveAttribute()

◆ testLegendAttribute()

◆ testPaintAttribute()