Qwt User's Guide  6.2.0
QwtPlotBarChart Class Reference

QwtPlotBarChart displays a series of a values as bars. More...

#include <qwt_plot_barchart.h>

Inheritance diagram for QwtPlotBarChart:

Public Types

enum  LegendMode { LegendChartTitle , LegendBarTitles }
 Legend modes. More...
 
- Public Types inherited from QwtPlotAbstractBarChart
enum  LayoutPolicy { AutoAdjustSamples , ScaleSamplesToAxes , ScaleSampleToCanvas , FixedSampleSize }
 Mode how to calculate the bar width. 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. More...
 
enum  RenderHint { RenderAntialiased = 0x1 }
 Render hints. More...
 
typedef QFlags< ItemAttributeItemAttributes
 
typedef QFlags< ItemInterestItemInterests
 
typedef QFlags< RenderHintRenderHints
 

Public Member Functions

 QwtPlotBarChart (const QString &title=QString())
 
 QwtPlotBarChart (const QwtText &title)
 
virtual ~QwtPlotBarChart ()
 Destructor.
 
virtual int rtti () const override
 
void setSamples (const QVector< QPointF > &)
 
void setSamples (const QVector< double > &)
 
void setSamples (QwtSeriesData< QPointF > *)
 
void setSymbol (QwtColumnSymbol *)
 Assign a symbol. More...
 
const QwtColumnSymbolsymbol () const
 
void setLegendMode (LegendMode)
 
LegendMode legendMode () const
 
virtual void drawSeries (QPainter *, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect, int from, int to) const override
 
virtual QRectF boundingRect () const override
 
virtual QwtColumnSymbolspecialSymbol (int sampleIndex, const QPointF &) const
 
virtual QwtText barTitle (int sampleIndex) const
 Return the title of a bar. More...
 
- Public Member Functions inherited from QwtPlotAbstractBarChart
 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. More...
 
int spacing () const
 
void setMargin (int)
 Set the margin. More...
 
int margin () const
 
void setBaseline (double)
 Set the baseline. More...
 
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. More...
 
- 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. More...
 
virtual void updateScaleDiv (const QwtScaleDiv &, const QwtScaleDiv &) override
 Update the item to changes of the axes scale division. More...
 
- 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. More...
 
void detach ()
 This method detaches a QwtPlotItem from any QwtPlot it has been associated with. More...
 
QwtPlotplot () const
 Return attached plot.
 
void setTitle (const QString &title)
 
void setTitle (const QwtText &title)
 
const QwtTexttitle () 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 (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. 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...
 
- Public Member Functions inherited from QwtAbstractSeriesStore
virtual ~QwtAbstractSeriesStore ()
 Destructor.
 
- Public Member Functions inherited from QwtSeriesStore< QPointF >
 QwtSeriesStore ()
 Constructor The store contains no series.
 
 ~QwtSeriesStore ()
 Destructor.
 
void setData (QwtSeriesData< QPointF > *series)
 
QwtSeriesData< QPointF > * data ()
 
const QwtSeriesData< QPointF > * data () const
 
QPointF sample (int index) const
 
virtual size_t dataSize () const override
 
virtual QRectF dataRect () const override
 
virtual void setRectOfInterest (const QRectF &rect) override
 
QwtSeriesData< QPointF > * swapData (QwtSeriesData< QPointF > *series)
 

Protected Member Functions

virtual void drawSample (QPainter *painter, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect, const QwtInterval &boundingInterval, int index, const QPointF &sample) const
 
virtual void drawBar (QPainter *, int sampleIndex, const QPointF &sample, const QwtColumnRect &) const
 
QwtColumnRect columnRect (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect, const QwtInterval &boundingInterval, const QPointF &sample) const
 
QList< QwtLegendDatalegendData () const override
 Return all information, that is needed to represent the item on the legend. More...
 
QwtGraphic legendIcon (int index, const QSizeF &) const override
 
- Protected Member Functions inherited from QwtPlotAbstractBarChart
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. More...
 

Detailed Description

QwtPlotBarChart displays a series of a values as bars.

Each bar might be customized individually by implementing a specialSymbol(). Otherwise it is rendered using a default symbol.

Depending on its orientation() the bars are displayed horizontally or vertically. The bars cover the interval between the baseline() and the value.

By activating the LegendBarTitles mode each sample will have its own entry on the legend.

The most common use case of a bar chart is to display a list of y coordinates, where the x coordinate is simply the index in the list. But for other situations ( f.e. when values are related to dates ) it is also possible to set x coordinates explicitly.

See also
QwtPlotMultiBarChart, QwtPlotHistogram, QwtPlotCurve::Sticks, QwtPlotSeriesItem::orientation(), QwtPlotAbstractBarChart::baseline()

Definition at line 41 of file qwt_plot_barchart.h.

Member Enumeration Documentation

◆ LegendMode

Legend modes.

The default setting is QwtPlotBarChart::LegendChartTitle.

See also
setLegendMode(), legendMode()
Enumerator
LegendChartTitle 

One entry on the legend showing the default symbol and the title() of the chart

See also
QwtPlotItem::title()
LegendBarTitles 

One entry for each value showing the individual symbol of the corresponding bar and the bar title.

See also
specialSymbol(), barTitle()

Definition at line 52 of file qwt_plot_barchart.h.

Constructor & Destructor Documentation

◆ QwtPlotBarChart() [1/2]

QwtPlotBarChart::QwtPlotBarChart ( const QString &  title = QString())
explicit

Constructor

Parameters
titleTitle of the curve

Definition at line 51 of file qwt_plot_barchart.cpp.

◆ QwtPlotBarChart() [2/2]

QwtPlotBarChart::QwtPlotBarChart ( const QwtText title)
explicit

Constructor

Parameters
titleTitle of the curve

Definition at line 41 of file qwt_plot_barchart.cpp.

Member Function Documentation

◆ barTitle()

QwtText QwtPlotBarChart::barTitle ( int  sampleIndex) const
virtual

Return the title of a bar.

In LegendBarTitles mode the title is displayed on the legend entry corresponding to a bar.

The default implementation is a dummy, that is intended to be overloaded.

Parameters
sampleIndexIndex of the bar
Returns
An empty text
See also
LegendBarTitles

Definition at line 399 of file qwt_plot_barchart.cpp.

◆ boundingRect()

QRectF QwtPlotBarChart::boundingRect ( ) const
overridevirtual
Returns
Bounding rectangle of all samples. For an empty series the rectangle is invalid.

Reimplemented from QwtPlotSeriesItem.

Definition at line 186 of file qwt_plot_barchart.cpp.

◆ columnRect()

QwtColumnRect QwtPlotBarChart::columnRect ( const QwtScaleMap xMap,
const QwtScaleMap yMap,
const QRectF &  canvasRect,
const QwtInterval boundingInterval,
const QPointF &  sample 
) const
protected

Calculate the geometry of a bar in widget coordinates

Parameters
xMapx map
yMapy map
canvasRectContents rect of the canvas
boundingIntervalBounding interval of sample values
sampleValue of the sample
Returns
Geometry of the column

Definition at line 262 of file qwt_plot_barchart.cpp.

◆ drawBar()

void QwtPlotBarChart::drawBar ( QPainter *  painter,
int  sampleIndex,
const QPointF &  sample,
const QwtColumnRect rect 
) const
protectedvirtual

Draw a bar

Parameters
painterPainter
sampleIndexIndex of the sample represented by the bar
sampleValue of the sample
rectBounding rectangle of the bar

Definition at line 341 of file qwt_plot_barchart.cpp.

◆ drawSample()

void QwtPlotBarChart::drawSample ( QPainter *  painter,
const QwtScaleMap xMap,
const QwtScaleMap yMap,
const QRectF &  canvasRect,
const QwtInterval boundingInterval,
int  index,
const QPointF &  sample 
) const
protectedvirtual

Draw a sample

Parameters
painterPainter
xMapx map
yMapy map
canvasRectContents rect of the canvas
boundingIntervalBounding interval of sample values
indexIndex of the sample
sampleValue of the sample
See also
drawSeries()

Definition at line 322 of file qwt_plot_barchart.cpp.

◆ drawSeries()

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

Draw an interval of the bar chart

Parameters
painterPainter
xMapMaps x-values into pixel coordinates.
yMapMaps y-values into pixel coordinates.
canvasRectContents rect of the canvas
fromIndex of the first point to be painted
toIndex of the last point to be painted. If to < 0 the curve will be painted to its last point.
See also
drawSymbols()

Implements QwtPlotSeriesItem.

Definition at line 223 of file qwt_plot_barchart.cpp.

◆ legendData()

QList< QwtLegendData > QwtPlotBarChart::legendData ( ) const
overrideprotectedvirtual

Return all information, that is needed to represent the item on the legend.

In case of LegendBarTitles an entry for each bar is returned, otherwise the chart is represented like any other plot item from its title() and the legendIcon().

Returns
Information, that is needed to represent the item on the legend
See also
title(), setLegendMode(), barTitle(), QwtLegend, QwtPlotLegendItem

Reimplemented from QwtPlotItem.

Definition at line 416 of file qwt_plot_barchart.cpp.

◆ legendIcon()

QwtGraphic QwtPlotBarChart::legendIcon ( int  index,
const QSizeF &  size 
) const
overrideprotectedvirtual
Returns
Icon representing a bar or the chart on the legend

When the legendMode() is LegendBarTitles the icon shows the bar corresponding to index - otherwise the bar displays the default symbol.

Parameters
indexIndex of the legend entry
sizeIcon size
See also
setLegendMode(), drawBar(), QwtPlotItem::setLegendIconSize(), QwtPlotItem::legendData()

Reimplemented from QwtPlotItem.

Definition at line 462 of file qwt_plot_barchart.cpp.

◆ legendMode()

QwtPlotBarChart::LegendMode QwtPlotBarChart::legendMode ( ) const
Returns
Legend mode
See also
setLegendMode()

Definition at line 177 of file qwt_plot_barchart.cpp.

◆ rtti()

int QwtPlotBarChart::rtti ( ) const
overridevirtual
Returns
QwtPlotItem::Rtti_PlotBarChart

Reimplemented from QwtPlotItem.

Definition at line 70 of file qwt_plot_barchart.cpp.

◆ setLegendMode()

void QwtPlotBarChart::setLegendMode ( LegendMode  mode)

Set the mode that decides what to display on the legend

In case of LegendBarTitles barTitle() needs to be overloaded to return individual titles for each bar.

Parameters
modeNew mode
See also
legendMode(), legendData(), barTitle(), QwtPlotItem::ItemAttribute

Definition at line 164 of file qwt_plot_barchart.cpp.

◆ setSamples() [1/3]

void QwtPlotBarChart::setSamples ( const QVector< double > &  samples)

Initialize data with an array of doubles

The indices in the array are taken as x coordinate, while the doubles are interpreted as y values.

Parameters
samplesVector of y coordinates
Note
QVector is implicitly shared

Definition at line 97 of file qwt_plot_barchart.cpp.

◆ setSamples() [2/3]

void QwtPlotBarChart::setSamples ( const QVector< QPointF > &  samples)

Initialize data with an array of points

Parameters
samplesVector of points
Note
QVector is implicitly shared
QPolygonF is derived from QVector<QPointF>

Definition at line 82 of file qwt_plot_barchart.cpp.

◆ setSamples() [3/3]

void QwtPlotBarChart::setSamples ( QwtSeriesData< QPointF > *  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
dataData
Warning
The item takes ownership of the data object, deleting it when its not used anymore.

Definition at line 119 of file qwt_plot_barchart.cpp.

◆ setSymbol()

void QwtPlotBarChart::setSymbol ( QwtColumnSymbol symbol)

Assign a symbol.

The bar chart will take the ownership of the symbol, hence the previously set symbol will be delete by setting a new one. If symbol is NULL no symbol will be drawn.

Parameters
symbolSymbol
See also
symbol()

Definition at line 134 of file qwt_plot_barchart.cpp.

◆ specialSymbol()

QwtColumnSymbol * QwtPlotBarChart::specialSymbol ( int  sampleIndex,
const QPointF &  sample 
) const
virtual

Needs to be overloaded to return a non default symbol for a specific sample

Parameters
sampleIndexIndex of the sample represented by the bar
sampleValue of the sample
Returns
NULL, indicating to use the default symbol

Definition at line 377 of file qwt_plot_barchart.cpp.

◆ symbol()

const QwtColumnSymbol * QwtPlotBarChart::symbol ( ) const
Returns
Current symbol or NULL, when no symbol has been assigned
See also
setSymbol()

Definition at line 150 of file qwt_plot_barchart.cpp.