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_PlotArrowMarker , Rtti_PlotBoxChart , Rtti_PlotUserItem = 1000 }
	Runtime type information. More...

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

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

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

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

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

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

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

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
	Get the pen used in a style() depending way.

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

const QBrush &	brush () const
	Get the brush used in a style() depending way.

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
	Get the value of the baseline.

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

HistogramStyle	style () const
	Get the histogram's drawing style.

void	setSymbol (const QwtColumnSymbol *)
	Assign a symbol.

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

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

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

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

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

	QwtPlotSeriesItem (const QwtText &title)
	Constructor.

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

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

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

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

Public Member Functions inherited from QwtPlotItem
	QwtPlotItem ()
	Default constructor.

	QwtPlotItem (const QString &title)
	Constructor with title as QString.

	QwtPlotItem (const QwtText &title)
	Constructor with title as QwtText.

virtual	~QwtPlotItem ()
	Destructor.

void	detach ()
	Detach the item from the plot.

QwtPlot *	plot () const
	Get the plot the item is attached to.

void	setTitle (const QString &title)
	Set the title using a QString.

void	setTitle (const QwtText &title)
	Set the title using a QwtText.

const QwtText &	title () const
	Get the title.

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

bool	testItemAttribute (ItemAttribute) const
	Test an item attribute.

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

bool	testItemInterest (ItemInterest) const
	Test an item interest.

void	setRenderHint (RenderHint, bool on=true)
	Set a render hint.

bool	testRenderHint (RenderHint) const
	Test a render hint.

void	setRenderThreadCount (uint numThreads)
	Set the number of render threads.

uint	renderThreadCount () const
	Get the number of render threads.

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

QSize	legendIconSize () const
	Get the legend icon size.

double	z () const
	Get the z-value.

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

void	show ()
	Show the item.

void	hide ()
	Hide the item.

virtual void	setVisible (bool)
	Set the visibility.

bool	isVisible () const
	Check if the item is visible.

void	setAxes (QwtAxisId xAxis, QwtAxisId yAxis)
	Set both axes.

void	setXAxis (QwtAxisId)
	Set the x-axis.

QwtAxisId	xAxis () const
	Get the x-axis.

void	setYAxis (QwtAxisId)
	Set the y-axis.

QwtAxisId	yAxis () const
	Get the y-axis.

virtual void	itemChanged ()
	Notify the plot that the item has changed.

virtual void	legendChanged ()
	Notify the item that the legend has changed.

virtual void	getCanvasMarginHint (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect, double &left, double &top, double &right, double &bottom) const
	Get margin hints for the canvas.

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

QRectF	scaleRect (const QwtScaleMap &, const QwtScaleMap &) const
	Calculate the scale rectangle.

QRectF	paintRect (const QwtScaleMap &, const QwtScaleMap &) const
	Calculate the paint rectangle.

virtual QList< QwtLegendData >	legendData () const
	Return legend data.

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

QwtSeriesData< QwtIntervalSample > *	data ()

const QwtSeriesData< QwtIntervalSample > *	data () const

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

Protected Member Functions
virtual QwtColumnRect	columnRect (const QwtIntervalSample &, const QwtScaleMap &, const QwtScaleMap &) const
	Get the column rectangle.

virtual void	drawColumn (QPainter *, const QwtColumnRect &, const QwtIntervalSample &) const
	Draw a column.

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

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

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

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

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

Detailed Description

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()

QwtPlotHistogram::QwtPlotHistogram ( const QwtText & title )

explicit

Constructor with QwtText title.

Parameters

[in] title Title of the histogram

Constructor with QString title

Parameters

[in] title Title of the histogram

Destructor

Member Function Documentation

◆ attach()

void QwtPlotHistogram::attach ( QwtPlot * plot )

overridevirtual

Attach the histogram to a plot.

If pen/brush have not been explicitly set by the user, the histogram automatically receives colors from the plot's color cycle.

Parameters

plot	Plot to attach to (nullptr to detach)

Reimplemented from QwtPlotItem.

◆ baseline()

double QwtPlotHistogram::baseline ( ) const

Get the value of the baseline.

Returns: Value of the baseline

See also: setBaseline()

◆ boundingRect()

QRectF QwtPlotHistogram::boundingRect ( ) const

overridevirtual

Get the bounding rectangle of all samples.

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

Reimplemented from QwtPlotSeriesItem.

◆ brush()

const QBrush & QwtPlotHistogram::brush ( ) const

Get the brush used in a style() depending way.

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

Get the column rectangle.

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.

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 columns.

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 lines.

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 outline.

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

overridevirtual

Draw a subset of the histogram samples.

Parameters

[in]	painter	Painter
[in]	xMap	Maps x-values into pixel coordinates
[in]	yMap	Maps y-values into pixel coordinates
[in]	canvasRect	Contents rectangle of the canvas
[in]	from	Index of the first sample to be painted
[in]	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

overridevirtual

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

Get the pen used in a style() depending way.

Returns: Pen used in a style() depending way

See also: setPen(), brush()

◆ rtti()

int QwtPlotHistogram::rtti ( ) const

overridevirtual

Get the runtime type information.

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

[in] 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

[in] 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) which makes it non cosmetic (see QPen::isCosmetic()). This method has been introduced to hide this incompatibility.

Parameters

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

See also: pen(), brush()

◆ setPen() [2/2]

void QwtPlotHistogram::setPen ( const QPen & pen )

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

Parameters

[in] 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

[in] 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

[in] data Data

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

◆ setStyle()

void QwtPlotHistogram::setStyle ( HistogramStyle style )

Set the histogram's drawing style.

Parameters

[in] 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().

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

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

◆ style()

QwtPlotHistogram::HistogramStyle QwtPlotHistogram::style ( ) const

Get the histogram's drawing style.

Returns: Style of the histogram

See also: HistogramStyle, setStyle()

◆ symbol()

const QwtColumnSymbol * QwtPlotHistogram::symbol ( ) const

Get the current symbol.

Returns: Current symbol or nullptr 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/plot/qwt_plot_histogram.h
/home/runner/work/QWT/QWT/src/plot/qwt_plot_histogram.cpp

Classes

Public Types

Public Member Functions

Protected Member Functions

Detailed Description

Member Enumeration Documentation

◆ HistogramStyle

Constructor & Destructor Documentation

◆ QwtPlotHistogram()

Member Function Documentation

◆ attach()

◆ 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()