#include <qwt_plot_curve.h>

Inheritance diagram for QwtPlotCurve:

Public Types
enum	CurveAttribute { Inverted = 1, Fitted = 2 }
enum	CurveStyle { NoCurve, Lines, Sticks, Steps, Dots, UserCurve = 100 }
enum	CurveType { Yfx, Xfy }
enum	PaintAttribute { PaintFiltered = 1, ClipPolygons = 2 }
Public Types inherited from QwtPlotItem
enum	ItemAttribute { Legend = 1, AutoScale = 2 }
enum	RenderHint { RenderAntialiased = 1 }
enum	RttiValues { Rtti_PlotItem = 0, Rtti_PlotGrid, Rtti_PlotScale, Rtti_PlotMarker, Rtti_PlotCurve, Rtti_PlotHistogram, Rtti_PlotSpectrogram, Rtti_PlotSVG, Rtti_PlotUserItem = 1000 }

Public Member Functions
	QwtPlotCurve ()
	QwtPlotCurve (const QwtText &title)
	QwtPlotCurve (const QString &title)
virtual	~QwtPlotCurve ()
double	baseline () const
virtual QwtDoubleRect	boundingRect () const
const QBrush &	brush () const
int	closestPoint (const QPoint &pos, double *dist=NULL) const
QwtCurveFitter *	curveFitter () const
CurveType	curveType () const
QwtData &	data ()
const QwtData &	data () const
int	dataSize () const
virtual void	draw (QPainter *p, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRect &) const
virtual void	draw (QPainter *p, const QwtScaleMap &xMap, const QwtScaleMap &yMap, int from, int to) const
void	draw (int from, int to) const
double	maxXValue () const
double	maxYValue () const
double	minXValue () const
double	minYValue () const
const QPen &	pen () const
virtual int	rtti () const
void	setBaseline (double ref)
void	setBrush (const QBrush &)
void	setCurveAttribute (CurveAttribute, bool on=true)
void	setCurveFitter (QwtCurveFitter *)
void	setCurveType (CurveType)
void	setData (const double xData, const double yData, int size)
void	setData (const QwtArray< double > &xData, const QwtArray< double > &yData)
void	setData (const QPolygonF &data)
void	setData (const QwtData &data)
void	setPaintAttribute (PaintAttribute, bool on=true)
void	setPen (const QPen &)
void	setRawData (const double x, const double y, int size)
void	setStyle (CurveStyle style)
void	setSymbol (const QwtSymbol &s)
CurveStyle	style () const
const QwtSymbol &	symbol () const
bool	testCurveAttribute (CurveAttribute) const
bool	testPaintAttribute (PaintAttribute) const
virtual void	updateLegend (QwtLegend *) const
double	x (int i) const
double	y (int i) const
Public Member Functions inherited from QwtPlotItem
	QwtPlotItem (const QwtText &title=QwtText())
virtual	~QwtPlotItem ()
void	attach (QwtPlot *plot)
void	detach ()
void	hide ()
QwtDoubleRect	invTransform (const QwtScaleMap &, const QwtScaleMap &, const QRect &) const
bool	isVisible () const
virtual void	itemChanged ()
virtual QWidget *	legendItem () const
QRect	paintRect (const QwtScaleMap &, const QwtScaleMap &) const
QwtPlot *	plot () const
QwtDoubleRect	scaleRect (const QwtScaleMap &, const QwtScaleMap &) const
void	setAxis (int xAxis, int yAxis)
void	setItemAttribute (ItemAttribute, bool on=true)
void	setRenderHint (RenderHint, bool on=true)
void	setTitle (const QString &title)
void	setTitle (const QwtText &title)
virtual void	setVisible (bool)
void	setXAxis (int axis)
void	setYAxis (int axis)
void	setZ (double z)
void	show ()
bool	testItemAttribute (ItemAttribute) const
bool	testRenderHint (RenderHint) const
const QwtText &	title () const
QRect	transform (const QwtScaleMap &, const QwtScaleMap &, const QwtDoubleRect &) const
virtual void	updateScaleDiv (const QwtScaleDiv &, const QwtScaleDiv &)
int	xAxis () const
int	yAxis () const
double	z () const
Public Member Functions inherited from QwtLegendItemManager
	QwtLegendItemManager ()
virtual	~QwtLegendItemManager ()

Protected Member Functions
void	closePolyline (const QwtScaleMap &, const QwtScaleMap &, QwtPolygon &) const
virtual void	drawCurve (QPainter *p, int style, const QwtScaleMap &xMap, const QwtScaleMap &yMap, int from, int to) const
void	drawDots (QPainter *p, const QwtScaleMap &xMap, const QwtScaleMap &yMap, int from, int to) const
void	drawLines (QPainter *p, const QwtScaleMap &xMap, const QwtScaleMap &yMap, int from, int to) const
void	drawSteps (QPainter *p, const QwtScaleMap &xMap, const QwtScaleMap &yMap, int from, int to) const
void	drawSticks (QPainter *p, const QwtScaleMap &xMap, const QwtScaleMap &yMap, int from, int to) const
virtual void	drawSymbols (QPainter *p, const QwtSymbol &, const QwtScaleMap &xMap, const QwtScaleMap &yMap, int from, int to) const
void	fillCurve (QPainter *, const QwtScaleMap &, const QwtScaleMap &, QwtPolygon &) const
void	init ()

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 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 QwtData object offering a bridge to the real storage of the points ( like QAbstractItemModel ). There are several convenience classes derived from QwtData, that also store the points inside ( like QStandardItemModel ). QwtPlotCurve also offers a couple of variations of setData(), that build QwtData objects from arrays internally.
c) Attach the curve to a plot: See QwtPlotItem::attach()

Example:: see examples/bode

See also:: QwtPlot, QwtData, QwtSymbol, QwtScaleMap

Member Enumeration Documentation

enum QwtPlotCurve::CurveAttribute

Attribute for drawing the curve

Fitted ( in combination with the Lines QwtPlotCurve::CurveStyle only )
A QwtCurveFitter tries to interpolate/smooth the curve, before it is painted. Note that curve fitting requires temorary memory for calculating coefficients and additional points. If painting in Fitted mode is slow it might be better to fit the points, before they are passed to QwtPlotCurve.
Inverted
For Steps only. Draws a step function from the right to the left.

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

enum QwtPlotCurve::CurveStyle

Curve styles.

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(Yfx) or horizontal(Xfy) sticks 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 '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 NoStyle style and a symbol painting a point.
UserCurve
Styles >= UserCurve are reserved for derived classes of QwtPlotCurve that overload drawCurve() with additional application specific curve types.

See also:: setStyle(), style()

enum QwtPlotCurve::CurveType

Curve type.

Yfx
Draws y as a function of x (the default). The baseline is interpreted as a horizontal line with y = baseline().
Xfy
Draws x as a function of y. The baseline is interpreted as a vertical line with x = baseline().

The baseline is used for aligning the sticks, or filling the curve with a brush.

See also:: setCurveType(), curveType(), baseline() brush()

enum QwtPlotCurve::PaintAttribute

Attributes to modify the drawing algorithm.

PaintFiltered
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 algos are implemented.
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 ( especially on Windows ).

The default is, that no paint attributes are enabled.

See also:: setPaintAttribute(), testPaintAttribute()

Constructor & Destructor Documentation

QwtPlotCurve::QwtPlotCurve ( const QwtText & title )

explicit

Constructor

Parameters:

title Title of the curve

QwtPlotCurve::QwtPlotCurve ( const QString & title )

explicit

Constructor

Parameters:

title Title of the curve

Member Function Documentation

double QwtPlotCurve::baseline ( ) const

Return the value of the baseline

See also:: setBaseline()

QwtDoubleRect QwtPlotCurve::boundingRect ( ) const

virtual

Returns the bounding rectangle of the curve data. If there is no bounding rect, like for empty data the rectangle is invalid.

See also:: QwtData::boundingRect(), QwtDoubleRect::isValid()

Reimplemented from QwtPlotItem.

const QBrush & QwtPlotCurve::brush ( ) const

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

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

void QwtPlotCurve::closePolyline	(	const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap,
		QwtPolygon &	pa
	)		const

protected

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

Parameters:

xMap	X map
yMap	Y map
pa	Polygon to be completed

int QwtPlotCurve::closestPoint	(	const QPoint &	pos,
		double *	dist = `NULL`
	)		const

Find the closest curve point for a specific position

Parameters:

pos	Position, where to look for the closest curve point
dist	If dist != NULL, closestPoint() returns the distance between the position and the clostest curve point

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

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

QwtCurveFitter * QwtPlotCurve::curveFitter ( ) const

Get the curve fitter. If curve fitting is disabled NULL is returned.

Returns:: Curve fitter

QwtPlotCurve::CurveType QwtPlotCurve::curveType ( ) const

Return the curve type

See also:: CurveType, setCurveType()

QwtData & QwtPlotCurve::data ( )

inline

Returns:: the the curve data

const QwtData & QwtPlotCurve::data ( ) const

inline

Returns:: the the curve data

int QwtPlotCurve::dataSize ( ) const

Return the size of the data arrays

See also:: setData()

void QwtPlotCurve::draw	(	QPainter *	painter,
		const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap,
		const QRect &	canvasRect
	)		const

virtual

Draw the complete curve.

Parameters:

painter	Painter
xMap	Maps x-values into pixel coordinates.
yMap	Maps y-values into pixel coordinates.

See also:: drawCurve(), drawSymbols()

Implements QwtPlotItem.

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

virtual

Draw an interval of the curve.

Parameters:

painter	Painter
xMap	maps x-values into pixel coordinates.
yMap	maps y-values into pixel coordinates.
from	index of the first point to be painted
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(),

void QwtPlotCurve::draw	(	int	from,
		int	to
	)		const

Draw a set of points of a curve.

When observing an measurement while it is running, new points have to be added to an existing curve. drawCurve can be used to display them avoiding a complete redraw of the canvas.

Setting plot()->canvas()->setAttribute(Qt::WA_PaintOutsidePaintEvent, true); will result in faster painting, if the paint engine of the canvas widget supports this feature.

Parameters:

from	Index of the first point to be painted
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()

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

protectedvirtual

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

Parameters:

painter	Painter
style	curve style, see QwtPlotCurve::CurveStyle
xMap	x map
yMap	y map
from	index of the first point to be painted
to	index of the last point to be painted

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

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

protected

Draw dots

Parameters:

painter	Painter
xMap	x map
yMap	y map
from	index of the first point to be painted
to	index of the last point to be painted

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

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

protected

Draw lines.

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

Parameters:

painter	Painter
xMap	x map
yMap	y map
from	index of the first point to be painted
to	index of the last point to be painted

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

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

protected

Draw step function

The direction of the steps depends on Inverted attribute.

Parameters:

painter	Painter
xMap	x map
yMap	y map
from	index of the first point to be painted
to	index of the last point to be painted

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

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

protected

Draw sticks

Parameters:

painter	Painter
xMap	x map
yMap	y map
from	index of the first point to be painted
to	index of the last point to be painted

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

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

protectedvirtual

Draw symbols.

Parameters:

painter	Painter
symbol	Curve symbol
xMap	x map
yMap	y map
from	index of the first point to be painted
to	index of the last point to be painted

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

void QwtPlotCurve::fillCurve	(	QPainter *	painter,
		const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap,
		QwtPolygon &	pa
	)		const

protected

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

Parameters:

painter	Painter
xMap	x map
yMap	y map
pa	Polygon

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

const QPen & QwtPlotCurve::pen ( ) const

Return the pen used to draw the lines.

See also:: setPen(), brush()

int QwtPlotCurve::rtti ( ) const

virtual

Returns:: QwtPlotItem::Rtti_PlotCurve

Reimplemented from QwtPlotItem.

void QwtPlotCurve::setBaseline ( double reference )

Set the value of the baseline.

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

Parameters:

reference baseline

See also:: baseline(), setBrush(), setStyle(), setCurveType()

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:

brush New brush

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

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

Specify an attribute for drawing the curve

Parameters:

attribute	Curve attribute
on	On/Off

/sa CurveAttribute, testCurveAttribute(), setCurveFitter()

void QwtPlotCurve::setCurveFitter ( QwtCurveFitter * curveFitter )

Assign a curve fitter setCurveFitter(NULL) disables curve fitting.

Parameters:

curveFitter Curve fitter

void QwtPlotCurve::setCurveType ( CurveType curveType )

Assign the curve type

Parameters:

curveType Yfx or Xfy

See also:: CurveType, curveType()

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

Set data by copying x- and y-values from specified memory blocks. Contrary to setCurveRawData(), this function makes a 'deep copy' of the data.

Parameters:

xData	Pointer to x values
yData	Pointer to y values
size	Size of xData and yData

Note:: Internally the data is stored in a QwtArrayData object

void QwtPlotCurve::setData	(	const QwtArray< double > &	xData,
		const QwtArray< double > &	yData
	)

Initialize data with x- and y-arrays (explicitly shared) ( Builds an QwtArrayData object internally )

Parameters:

xData	x data
yData	y data

Note:: Internally the data is stored in a QwtArrayData object

void QwtPlotCurve::setData ( const QPolygonF & data )

Initialize data with an array of points (explicitly shared).

Parameters:

data Data

Note:: Internally the data is stored in a QwtPolygonFData object

void QwtPlotCurve::setData ( const QwtData & data )

Initialize data with a pointer to QwtData.

Parameters:

data Data

See also:: QwtData::copy()

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

Specify an attribute how to draw the curve

Parameters:

attribute	Paint attribute
on	On/Off /sa PaintAttribute, testPaintAttribute()

void QwtPlotCurve::setPen ( const QPen & pen )

Assign a pen

The width of non cosmetic pens is scaled according to the resolution of the paint device.

Parameters:

pen New pen

See also:: pen(), brush(), QwtPainter::scaledPen()

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

Initialize the data by pointing to memory blocks which are not managed by QwtPlotCurve.

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

Parameters:

xData	pointer to x data
yData	pointer to y data
size	size of x and y

Note:: Internally the data is stored in a QwtCPointerData object

void QwtPlotCurve::setStyle ( CurveStyle style )

Set the curve's drawing style

Parameters:

style Curve style

See also:: CurveStyle, style()

void QwtPlotCurve::setSymbol ( const QwtSymbol & symbol )

Assign a symbol.

Parameters:

symbol Symbol

See also:: symbol()

QwtPlotCurve::CurveStyle QwtPlotCurve::style ( ) const

Return the current style

See also:: CurveStyle, setStyle()

const QwtSymbol & QwtPlotCurve::symbol ( ) const

Return the current symbol.

See also:: setSymbol()

bool QwtPlotCurve::testCurveAttribute ( CurveAttribute attribute ) const

Returns:: true, if attribute is enabled

See also:: CurveAttribute, setCurveAttribute()

bool QwtPlotCurve::testPaintAttribute ( PaintAttribute attribute ) const

Return the current paint attributes.

See also:: PaintAttribute, setPaintAttribute()

double QwtPlotCurve::x ( int i ) const

inline

Parameters:

i index

Returns:: x-value at position i

double QwtPlotCurve::y ( int i ) const

inline

Parameters:

i index

Returns:: y-value at position i

Public Types

Public Member Functions

Protected Member Functions

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation