QwtPlotAbstractBarChart - Abstract base class for bar chart items.

NAME

QwtPlotAbstractBarChart − Abstract base class for bar chart items.

SYNOPSIS

#include <qwt_plot_abstract_barchart.h>

Inherits QwtPlotSeriesItem.

Inherited by QwtPlotBarChart, and QwtPlotMultiBarChart.

Public Types

enum LayoutPolicy { AutoAdjustSamples, ScaleSamplesToAxes, ScaleSampleToCanvas, FixedSampleSize }
Mode how to calculate the bar width.

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.
enum ItemAttribute { Legend = 0x01, AutoScale = 0x02, Margins = 0x04 }
Plot Item Attributes.
enum ItemInterest { ScaleInterest = 0x01, LegendInterest = 0x02 }
Plot Item Interests.
enum RenderHint { RenderAntialiased = 0x1 }
Render hints.
typedef QFlags< ItemAttribute > ItemAttributes
typedef QFlags< ItemInterest > ItemInterests
typedef QFlags< RenderHint > RenderHints

Public Member Functions

QwtPlotAbstractBarChart (const QwtText &title)
virtual ˜QwtPlotAbstractBarChart ()
Destructor.
void setLayoutPolicy (LayoutPolicy)
LayoutPolicy layoutPolicy () const
void setLayoutHint (double)
double layoutHint () const
void setSpacing (int)
Set the spacing.
int spacing () const
void setMargin (int)
Set the margin.
int margin () const
void setBaseline (double)
Set the baseline.
double baseline () const
virtual void getCanvasMarginHint (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect, double &left, double &top, double &right, double &bottom) const override
Calculate a hint for the canvas margin.

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 &canvasRect) const override
Draw the complete series.
virtual void drawSeries (QPainter *painter, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect, int from, int to) const =0
virtual QRectF boundingRect () const override
virtual void updateScaleDiv (const QwtScaleDiv &, const QwtScaleDiv &) override
Update the item to changes of the axes scale division.

Public Member Functions inherited from QwtPlotItem

QwtPlotItem ()
QwtPlotItem (const QString &title)
QwtPlotItem (const QwtText &title)
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)
void setTitle (const QwtText &title)
const QwtText & title () const
virtual int rtti () 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.
void show ()
Show the item.
void hide ()
Hide the item.
virtual void setVisible (bool)
bool isVisible () const
void setAxes (QwtAxisId xAxis, QwtAxisId yAxis)
void setXAxis (QwtAxisId)
QwtAxisId xAxis () const
Return xAxis.
void setYAxis (QwtAxisId)
QwtAxisId yAxis () const
Return yAxis.
virtual void itemChanged ()
virtual void legendChanged ()
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.
virtual QwtGraphic legendIcon (int index, const QSizeF &) const

Public Member Functions inherited from QwtAbstractSeriesStore

virtual ˜QwtAbstractSeriesStore ()
Destructor.

Protected Member Functions

double sampleWidth (const QwtScaleMap &map, double canvasSize, double boundingSize, double value) const

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
Return a default icon from a brush.

Protected Member Functions inherited from QwtAbstractSeriesStore

virtual void setRectOfInterest (const QRectF &)=0
virtual QRectF dataRect () const =0
virtual size_t dataSize () const =0

Detailed Description

Abstract base class for bar chart items.

In opposite to almost all other plot items bar charts can’t be displayed inside of their bounding rectangle and need a special API how to calculate the width of the bars and how they affect the layout of the attached plot.

Definition at line 24 of file qwt_plot_abstract_barchart.h.

Member Enumeration Documentation

enum QwtPlotAbstractBarChart::LayoutPolicy

Mode how to calculate the bar width. setLayoutPolicy(), setLayoutHint(), barWidthHint()

Enumerator
AutoAdjustSamples

The sample width is calculated by dividing the bounding rectangle by the number of samples. The layoutHint() is used as a minimum width in paint device coordinates.

See also

boundingRectangle()

ScaleSamplesToAxes

layoutHint() defines an interval in axis coordinates

ScaleSampleToCanvas

The bar width is calculated by multiplying layoutHint() with the height or width of the canvas.

See also

boundingRectangle()

FixedSampleSize

layoutHint() defines a fixed width in paint device coordinates.

Definition at line 32 of file qwt_plot_abstract_barchart.h.

Constructor & Destructor Documentation

QwtPlotAbstractBarChart::QwtPlotAbstractBarChart (const QwtText & title)[explicit]

Constructor

Parameters

title Title of the chart

Definition at line 48 of file qwt_plot_abstract_barchart.cpp.

QwtPlotAbstractBarChart::˜QwtPlotAbstractBarChart () [virtual]

Destructor.

Definition at line 60 of file qwt_plot_abstract_barchart.cpp.

Member Function Documentation

double QwtPlotAbstractBarChart::baseline () const

Returns

Value for the origin of the bar chart

See also

setBaseline(), QwtPlotSeriesItem::orientation()

Definition at line 208 of file qwt_plot_abstract_barchart.cpp.

void QwtPlotAbstractBarChart::getCanvasMarginHint (const QwtScaleMap &xMap, const QwtScaleMap & yMap, const QRectF & canvasRect, double &left, double & top, double & right, double & bottom) const [override],[virtual]

Calculate a hint for the canvas margin. Bar charts need to reserve some space for displaying the bars for the first and the last sample. The hint is calculated from the layoutHint() depending on the layoutPolicy().

The margins are in target device coordinates ( pixels on screen )

Parameters

xMap Maps x-values into pixel coordinates.
yMap Maps y-values into pixel coordinates.
canvasRect Contents rectangle of the canvas in painter coordinates
left Returns the left margin
top Returns the top margin
right Returns the right margin
bottom Returns the bottom margin

See also

layoutPolicy(), layoutHint(), QwtPlotItem::Margins QwtPlot::getCanvasMarginsHint(), QwtPlot::updateCanvasMargins()

Reimplemented from QwtPlotItem.

Definition at line 287 of file qwt_plot_abstract_barchart.cpp.

double QwtPlotAbstractBarChart::layoutHint () const

The combination of layoutPolicy() and layoutHint() define how the width of the bars is calculated

Returns

Layout policy of the chart item

See also

LayoutPolicy, setLayoutHint(), layoutPolicy()

Definition at line 119 of file qwt_plot_abstract_barchart.cpp.

QwtPlotAbstractBarChart::LayoutPolicy QwtPlotAbstractBarChart::layoutPolicy() const

The combination of layoutPolicy() and layoutHint() define how the width of the bars is calculated

Returns

Layout policy of the chart item

See also

setLayoutPolicy(), layoutHint()

Definition at line 89 of file qwt_plot_abstract_barchart.cpp.

int QwtPlotAbstractBarChart::margin () const

Returns

Margin between the outmost bars and the contentsRect() of the canvas.

See also

setMargin(), spacing()

Definition at line 176 of file qwt_plot_abstract_barchart.cpp.

double QwtPlotAbstractBarChart::sampleWidth (const QwtScaleMap & map,double canvasSize, double boundingSize, double value) const [protected]

Calculate the width for a sample in paint device coordinates

Parameters

map Scale map for the corresponding scale
canvasSize Size of the canvas in paint device coordinates
boundingSize Bounding size of the chart in plot coordinates ( used in AutoAdjustSamples mode )
value Value of the sample

Returns

Sample width

See also

layoutPolicy(), layoutHint()

Definition at line 225 of file qwt_plot_abstract_barchart.cpp.

void QwtPlotAbstractBarChart::setBaseline (double value)

Set the baseline. The baseline is the origin for the chart. Each bar is painted from the baseline in the direction of the sample value. In case of a horizontal orientation() the baseline is interpreted as x - otherwise as y - value.

The default value for the baseline is 0.

Parameters

value Value for the baseline

See also

baseline(), QwtPlotSeriesItem::orientation()

Definition at line 195 of file qwt_plot_abstract_barchart.cpp.

void QwtPlotAbstractBarChart::setLayoutHint (double hint)

The combination of layoutPolicy() and layoutHint() define how the width of the bars is calculated

Parameters

hint Layout hint

See also

LayoutPolicy, layoutPolicy(), layoutHint()

Definition at line 102 of file qwt_plot_abstract_barchart.cpp.

void QwtPlotAbstractBarChart::setLayoutPolicy (LayoutPolicy policy)

The combination of layoutPolicy() and layoutHint() define how the width of the bars is calculated

Parameters

policy Layout policy

See also

layoutPolicy(), layoutHint()

Definition at line 73 of file qwt_plot_abstract_barchart.cpp.

void QwtPlotAbstractBarChart::setMargin (int margin)

Set the margin. The margin is the distance between the outmost bars and the contentsRect() of the canvas. The default setting is 5 pixels.

Parameters

margin Margin

See also

spacing(), margin()

Definition at line 160 of file qwt_plot_abstract_barchart.cpp.

void QwtPlotAbstractBarChart::setSpacing (int spacing)

Set the spacing. The spacing is the distance between 2 samples ( bars for QwtPlotBarChart or a group of bars for QwtPlotMultiBarChart ) in paint device coordinates.

See also

spacing()

Definition at line 132 of file qwt_plot_abstract_barchart.cpp.

int QwtPlotAbstractBarChart::spacing () const

Returns

Spacing between 2 samples ( bars or groups of bars )

See also

setSpacing(), margin()

Definition at line 146 of file qwt_plot_abstract_barchart.cpp.

Author

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Updated 2026-06-01 - jenkler.se | uex.se