QwtPlotHistogram represents a series of samples, where an interval is associated with a value ( ). More...

#include <qwt_plot_histogram.h>

Inheritance diagram for QwtPlotHistogram:

[legend]

Public Types
enum	HistogramStyle { Outline, Columns, Lines, UserStyle = 100 }

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_PlotSVG, Rtti_PlotTradingCurve, Rtti_PlotBarChart, Rtti_PlotMultiBarChart, Rtti_PlotShape, Rtti_PlotTextLabel, Rtti_PlotZone, 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...

typedef QFlags< ItemAttribute >	ItemAttributes
	Plot Item Attributes.

typedef QFlags< ItemInterest >	ItemInterests
	Plot Item Interests.

typedef QFlags< RenderHint >	RenderHints
	Render hints.

Public Member Functions
	QwtPlotHistogram (const QString &title=QString())

	QwtPlotHistogram (const QwtText &title)

virtual	~QwtPlotHistogram ()
	Destructor.

virtual int	rtti () const

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

void	setPen (const QPen &)

const QPen &	pen () const

void	setBrush (const QBrush &)

const QBrush &	brush () const

void	setSamples (const QVector< QwtIntervalSample > &)

void	setSamples (QwtSeriesData< QwtIntervalSample > *)

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

double	baseline () const

void	setStyle (HistogramStyle style)

HistogramStyle	style () const

void	setSymbol (const QwtColumnSymbol *)
	Assign a symbol. More...

const QwtColumnSymbol *	symbol () const

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

virtual QRectF	boundingRect () const

virtual QwtGraphic	legendIcon (int index, const QSizeF &) const

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

	QwtPlotSeriesItem (const QwtText &title)

virtual	~QwtPlotSeriesItem ()
	Destructor.

void	setOrientation (Qt::Orientation)

Qt::Orientation	orientation () const

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

virtual void	updateScaleDiv (const QwtScaleDiv &, const QwtScaleDiv &)
	Update the item to changes of the axes scale division. More...

Public Member Functions inherited from QwtPlotItem
	QwtPlotItem (const QwtText &title=QwtText())

virtual	~QwtPlotItem ()
	Destroy the QwtPlotItem.

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

void	detach ()
	This method detaches a QwtPlotItem from any QwtPlot it has been associated with. More...

QwtPlot *	plot () const
	Return attached plot.

void	setTitle (const QString &title)

void	setTitle (const QwtText &title)

const QwtText &	title () const

void	setItemAttribute (ItemAttribute, bool on=true)

bool	testItemAttribute (ItemAttribute) const

void	setItemInterest (ItemInterest, bool on=true)

bool	testItemInterest (ItemInterest) const

void	setRenderHint (RenderHint, bool on=true)

bool	testRenderHint (RenderHint) const

void	setRenderThreadCount (uint numThreads)

uint	renderThreadCount () const

void	setLegendIconSize (const QSize &)

QSize	legendIconSize () const

double	z () const

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

void	show ()
	Show the item.

void	hide ()
	Hide the item.

virtual void	setVisible (bool)

bool	isVisible () const

void	setAxes (int xAxis, int yAxis)

void	setXAxis (int axis)

int	xAxis () const
	Return xAxis.

void	setYAxis (int axis)

int	yAxis () const
	Return yAxis.

virtual void	itemChanged ()

virtual void	legendChanged ()

virtual void	getCanvasMarginHint (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect, double &left, double &top, double &right, double &bottom) const
	Calculate a hint for the canvas margin. More...

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

QRectF	scaleRect (const QwtScaleMap &, const QwtScaleMap &) const
	Calculate the bounding scale rectangle of 2 maps. More...

QRectF	paintRect (const QwtScaleMap &, const QwtScaleMap &) const
	Calculate the bounding paint rectangle of 2 maps. More...

virtual QList< QwtLegendData >	legendData () const
	Return all information, that is needed to represent the item on the legend. More...

Public Member Functions inherited from QwtSeriesStore< QwtIntervalSample >
	QwtSeriesStore ()
	Constructor The store contains no series.

	~QwtSeriesStore ()
	Destructor.

void	setData (QwtSeriesData< QwtIntervalSample > *series)

QwtSeriesData< QwtIntervalSample > *	data ()

const QwtSeriesData< QwtIntervalSample > *	data () const

QwtIntervalSample	sample (int index) const

virtual size_t	dataSize () const

virtual QRectF	dataRect () const

virtual void	setRectOfInterest (const QRectF &rect)

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

Protected Member Functions
virtual QwtColumnRect	columnRect (const QwtIntervalSample &, const QwtScaleMap &, const QwtScaleMap &) const

virtual void	drawColumn (QPainter *, const QwtColumnRect &, const QwtIntervalSample &) const

void	drawColumns (QPainter *, const QwtScaleMap &xMap, const QwtScaleMap &yMap, int from, int to) const

void	drawOutline (QPainter *, const QwtScaleMap &xMap, const QwtScaleMap &yMap, int from, int to) const

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

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

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

Protected Member Functions inherited from QwtAbstractSeriesStore
virtual	~QwtAbstractSeriesStore ()
	Destructor.

virtual QRectF	dataRect () const =0

virtual size_t	dataSize () const =0

Detailed Description

QwtPlotHistogram represents a series of samples, where an interval is associated with a value ( ).

The representation depends on the style() and an optional symbol() that is displayed for each interval.

Note: The term "histogram" is used in a different way in the areas of digital image processing and statistics. Wikipedia introduces the terms "image histogram" and "color histogram" to avoid confusions. While "image histograms" can be displayed by a QwtPlotCurve there is no applicable plot item for a "color histogram" yet.

See also: QwtPlotBarChart, QwtPlotMultiBarChart

Member Enumeration Documentation

◆ HistogramStyle

enum QwtPlotHistogram::HistogramStyle

Histogram styles. The default style is QwtPlotHistogram::Columns.

See also: setStyle(), style(), setSymbol(), symbol(), setBaseline()

Enumerator
Outline	Draw an outline around the area, that is build by all intervals using the pen() and fill it with the brush(). The outline style requires, that the intervals are in increasing order and not overlapping.
Columns	Draw a column for each interval. When a symbol() has been set the symbol is used otherwise the column is displayed as plain rectangle using pen() and brush().
Lines	Draw a simple line using the pen() for each interval.
UserStyle	Styles >= UserStyle are reserved for derived classes that overload drawSeries() with additional application specific ways to display a histogram.

Constructor & Destructor Documentation

◆ QwtPlotHistogram() [1/2]

QwtPlotHistogram::QwtPlotHistogram ( const QString & title = QString() )

explicit

Constructor

Parameters

title Title of the histogram.

◆ QwtPlotHistogram() [2/2]

QwtPlotHistogram::QwtPlotHistogram ( const QwtText & title )

explicit

Constructor

Parameters

title Title of the histogram.

Member Function Documentation

◆ baseline()

double QwtPlotHistogram::baseline ( ) const

Returns: Value of the baseline

See also: setBaseline()

◆ boundingRect()

QRectF QwtPlotHistogram::boundingRect ( ) const

virtual

Returns: Bounding rectangle of all samples. For an empty series the rectangle is invalid.

Reimplemented from QwtPlotSeriesItem.

◆ brush()

const QBrush & QwtPlotHistogram::brush ( ) const

Returns: Brush used in a style() depending way.

See also: setPen(), brush()

◆ columnRect()

QwtColumnRect QwtPlotHistogram::columnRect	(	const QwtIntervalSample &	sample,
		const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap
	)		const

protectedvirtual

Calculate the area that is covered by a sample

Parameters

sample	Sample
xMap	Maps x-values into pixel coordinates.
yMap	Maps y-values into pixel coordinates.

Returns: Rectangle, that is covered by a sample

◆ drawColumn()

void QwtPlotHistogram::drawColumn	(	QPainter *	painter,
		const QwtColumnRect &	rect,
		const QwtIntervalSample &	sample
	)		const

protectedvirtual

Draw a column for a sample in Columns style().

When a symbol() has been set the symbol is used otherwise the column is displayed as plain rectangle using pen() and brush().

Parameters

painter	Painter
rect	Rectangle where to paint the column in paint device coordinates
sample	Sample to be displayed

Note: In applications, where different intervals need to be displayed in a different way ( f.e different colors or even using different symbols) it is recommended to overload drawColumn().

◆ drawColumns()

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

protected

Draw a histogram in Columns style()

Parameters

painter	Painter
xMap	Maps x-values into pixel coordinates.
yMap	Maps y-values into pixel coordinates.
from	Index of the first sample to be painted
to	Index of the last sample to be painted. If to < 0 the histogram will be painted to its last point.

See also: setStyle(), style(), setSymbol(), drawColumn()

◆ drawLines()

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

protected

Draw a histogram in Lines style()

Parameters

painter	Painter
xMap	Maps x-values into pixel coordinates.
yMap	Maps y-values into pixel coordinates.
from	Index of the first sample to be painted
to	Index of the last sample to be painted. If to < 0 the histogram will be painted to its last point.

See also: setStyle(), style(), setPen()

◆ drawOutline()

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

protected

Draw a histogram in Outline style()

Parameters

painter	Painter
xMap	Maps x-values into pixel coordinates.
yMap	Maps y-values into pixel coordinates.
from	Index of the first sample to be painted
to	Index of the last sample to be painted. If to < 0 the histogram will be painted to its last point.

See also: setStyle(), style()

Warning: The outline style requires, that the intervals are in increasing order and not overlapping.

◆ drawSeries()

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

virtual

Draw a subset of the histogram samples

Parameters

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

See also: drawOutline(), drawLines(), drawColumns

Implements QwtPlotSeriesItem.

◆ legendIcon()

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

virtual

A plain rectangle without pen using the brush()

Parameters

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

Returns: A graphic displaying the icon

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

Reimplemented from QwtPlotItem.

◆ pen()

const QPen & QwtPlotHistogram::pen ( ) const

Returns: Pen used in a style() depending way.

See also: setPen(), brush()

◆ rtti()

int QwtPlotHistogram::rtti ( ) const

virtual

Returns: QwtPlotItem::Rtti_PlotHistogram

Reimplemented from QwtPlotItem.

◆ setBaseline()

void QwtPlotHistogram::setBaseline ( double value )

Set the value of the baseline.

Each column representing an QwtIntervalSample is defined by its interval and the interval between baseline and the value of the sample.

The default value of the baseline is 0.0.

Parameters

value Value of the baseline

See also: baseline()

◆ setBrush()

void QwtPlotHistogram::setBrush ( const QBrush & brush )

Assign a brush, that is used in a style() depending way.

Parameters

brush New brush

See also: pen(), brush()

◆ setPen() [1/2]

void QwtPlotHistogram::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 ) what makes it non cosmetic ( see QPen::isCosmetic() ). This method has been introduced to hide this incompatibility.

Parameters

color	Pen color
width	Pen width
style	Pen style

See also: pen(), brush()

◆ setPen() [2/2]

void QwtPlotHistogram::setPen ( const QPen & pen )

Assign a pen, that is used in a style() depending way.

Parameters

pen New pen

See also: pen(), brush()

◆ setSamples() [1/2]

void QwtPlotHistogram::setSamples ( const QVector< QwtIntervalSample > & samples )

Initialize data with an array of samples.

Parameters

samples Vector of points

◆ setSamples() [2/2]

void QwtPlotHistogram::setSamples ( QwtSeriesData< QwtIntervalSample > * data )

Assign a series of samples

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

Parameters

data Data

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

◆ setStyle()

void QwtPlotHistogram::setStyle ( HistogramStyle style )

Set the histogram's drawing style

Parameters

style Histogram style

See also: HistogramStyle, style()

◆ setSymbol()

void QwtPlotHistogram::setSymbol ( const QwtColumnSymbol * symbol )

Assign a symbol.

In Column style an optional symbol can be assigned, that is responsible for displaying the rectangle that is defined by the interval and the distance between baseline() and value. When no symbol has been defined the area is displayed as plain rectangle using pen() and brush().

See also: style(), symbol(), drawColumn(), pen(), brush()

Note: In applications, where different intervals need to be displayed in a different way ( f.e different colors or even using different symbols) it is recommended to overload drawColumn().

◆ style()

QwtPlotHistogram::HistogramStyle QwtPlotHistogram::style ( ) const

Returns: Style of the histogram

See also: HistogramStyle, setStyle()

◆ symbol()

const QwtColumnSymbol * QwtPlotHistogram::symbol ( ) const

Returns: Current symbol or NULL, when no symbol has been assigned

See also: setSymbol()

Public Types

Public Member Functions

Protected Member Functions

Detailed Description

Member Enumeration Documentation

◆ HistogramStyle

Constructor & Destructor Documentation

◆ QwtPlotHistogram() [1/2]

◆ QwtPlotHistogram() [2/2]

Member Function Documentation

◆ baseline()

◆ boundingRect()

◆ brush()

◆ columnRect()

◆ drawColumn()

◆ drawColumns()

◆ drawLines()

◆ drawOutline()

◆ drawSeries()

◆ legendIcon()

◆ pen()

◆ rtti()

◆ setBaseline()

◆ setBrush()

◆ setPen() [1/2]

◆ setPen() [2/2]

◆ setSamples() [1/2]

◆ setSamples() [2/2]

◆ setStyle()

◆ setSymbol()

◆ style()

◆ symbol()