QwtPlotHistogram represents a series of samples, where an interval is associated with a value ( $y = f([x1,x2])$ ). More...

#include <qwt_plot_histogram.h>

Inheritance diagram for QwtPlotHistogram:

Classes
class	PrivateData

Public Types
enum	HistogramStyle { Outline , Columns , Lines , UserStyle = 100 }
	Histogram styles. 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_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/绘图项关注的事件类型 More...

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

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

	QwtPlotHistogram (const QwtText &title)
	Constructor.

virtual	~QwtPlotHistogram ()
	Destructor.

virtual int	rtti () const QWT_OVERRIDE

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

void	setPen (const QPen &)
	Assign a pen, that is used in a style() depending way.

const QPen &	pen () const

void	setBrush (const QBrush &)
	Assign a brush, that is used in a style() depending way.

const QBrush &	brush () const

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

void	setSamples (QwtSeriesData< QwtIntervalSample > *)
	Assign a series of samples.

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

double	baseline () const

void	setStyle (HistogramStyle style)
	Set the histogram's drawing style.

HistogramStyle	style () const

void	setSymbol (const QwtColumnSymbol *)
	Assign a symbol.

const QwtColumnSymbol *	symbol () const

virtual void	drawSeries (QPainter *, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect, int from, int to) const QWT_OVERRIDE
	Draw a subset of the histogram samples.

virtual QRectF	boundingRect () const QWT_OVERRIDE

virtual QwtGraphic	legendIcon (int index, const QSizeF &) const QWT_OVERRIDE
	A plain rectangle without pen using the brush()

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

	QwtPlotSeriesItem (const QwtText &title)
	Constructor.

virtual	~QwtPlotSeriesItem ()
	Destructor.

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

Qt::Orientation	orientation () const

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

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

Public Member Functions inherited from QwtPlotItem
	QwtPlotItem ()
	Constructor.

	QwtPlotItem (const QString &title)
	Constructor.

	QwtPlotItem (const QwtText &title)
	Constructor.

virtual	~QwtPlotItem ()
	Destroy the QwtPlotItem.

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

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

QwtPlot *	plot () const
	Return attached plot.

void	setTitle (const QString &title)
	Set a new title.

void	setTitle (const QwtText &title)
	Set a new title.

const QwtText &	title () const

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

bool	testItemAttribute (ItemAttribute) const
	Test an item attribute.

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

bool	testItemInterest (ItemInterest) const
	Test an item interest.

void	setRenderHint (RenderHint, bool on=true)
	Toggle an render hint.

bool	testRenderHint (RenderHint) const
	Test a render hint.

void	setRenderThreadCount (uint numThreads)
	On multi core systems rendering of certain plot item ( f.e QwtPlotRasterItem ) can be done in parallel in several threads.

uint	renderThreadCount () const

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

QSize	legendIconSize () const

double	z () const
	Plot items are painted in increasing z-order.

void	setZ (double z)
	Set the z value.

void	show ()
	Show the item.

void	hide ()
	Hide the item.

virtual void	setVisible (bool)
	Show/Hide the item.

bool	isVisible () const

void	setAxes (QwtAxisId xAxis, QwtAxisId yAxis)
	Set X and Y axis.

void	setXAxis (QwtAxisId)
	Set the X axis.

QwtAxisId	xAxis () const
	Return xAxis.

void	setYAxis (QwtAxisId)
	Set the Y axis.

QwtAxisId	yAxis () const
	Return yAxis.

virtual void	itemChanged ()
	Update the legend and call QwtPlot::autoRefresh() for the parent plot.

virtual void	legendChanged ()
	Update the legend of the parent plot.

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.

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

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

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

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

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

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

	~QwtSeriesStore ()
	Destructor.

void	setData (QwtSeriesData< QwtIntervalSample > *series)
	Assign a series of samples.

QwtSeriesData< QwtIntervalSample > *	data ()

const QwtSeriesData< QwtIntervalSample > *	data () const

QwtIntervalSample	sample (size_t index) const

virtual size_t	dataSize () const QWT_OVERRIDE

virtual QRectF	dataRect () const QWT_OVERRIDE

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

QwtSeriesData< QwtIntervalSample > *	swapData (QwtSeriesData< QwtIntervalSample > *series)
	Replace a series without deleting the previous one.

Protected Member Functions
virtual QwtColumnRect	columnRect (const QwtIntervalSample &, const QwtScaleMap &, const QwtScaleMap &) const
	Calculate the area that is covered by a sample.

virtual void	drawColumn (QPainter *, const QwtColumnRect &, const QwtIntervalSample &) const
	Draw a column for a sample in Columns style().

void	drawColumns (QPainter *, const QwtScaleMap &xMap, const QwtScaleMap &yMap, int from, int to) const
	Draw a histogram in Columns style()

void	drawOutline (QPainter *, const QwtScaleMap &xMap, const QwtScaleMap &yMap, int from, int to) const
	Draw a histogram in Outline style()

void	drawLines (QPainter *, const QwtScaleMap &xMap, const QwtScaleMap &yMap, int from, int to) const
	Draw a histogram in Lines style()

Protected Member Functions inherited from QwtPlotSeriesItem
virtual void	dataChanged () QWT_OVERRIDE
	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.

Detailed Description

QwtPlotHistogram represents a series of samples, where an interval is associated with a value ( $y = f([x1,x2])$ ).

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()

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

/home/runner/work/QWT/QWT/src/qwt_plot_histogram.h
/home/runner/work/QWT/QWT/src/qwt_plot_histogram.cpp

Classes

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()