Qwt User's Guide  6.1.3
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_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< ItemAttributeItemAttributes
 Plot Item Attributes.
 
typedef QFlags< ItemInterestItemInterests
 Plot Item Interests.
 
typedef QFlags< RenderHintRenderHints
 Render hints.
 

Public Member Functions

 QwtPlotBarChart (const QString &title=QString::null)
 
 QwtPlotBarChart (const QwtText &title)
 
virtual ~QwtPlotBarChart ()
 Destructor.
 
virtual int rtti () const
 
void setSamples (const QVector< QPointF > &)
 
void setSamples (const QVector< double > &)
 
void setSamples (QwtSeriesData< QPointF > *series)
 
void setSymbol (QwtColumnSymbol *)
 Assign a symbol. More...
 
const QwtColumnSymbolsymbol () const
 
void setLegendMode (LegendMode)
 
LegendMode legendMode () const
 
virtual void drawSeries (QPainter *painter, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect, int from, int to) const
 
virtual QRectF boundingRect () const
 
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
 Calculate a hint for the canvas margin. More...
 
- Public Member Functions inherited from QwtPlotSeriesItem
 QwtPlotSeriesItem (const QString &title=QString::null)
 
 QwtPlotSeriesItem (const QwtText &title)
 
virtual ~QwtPlotSeriesItem ()
 Destructor.
 
void setOrientation (Qt::Orientation)
 
Qt::Orientation orientation () const
 
virtual void draw (QPainter *p, 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...
 
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 (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 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 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
 
virtual QRectF dataRect () const
 
virtual void setRectOfInterest (const QRectF &rect)
 
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 &point, const QwtColumnRect &) const
 
QList< QwtLegendDatalegendData () const
 Return all information, that is needed to represent the item on the legend. More...
 
QwtGraphic legendIcon (int index, const QSizeF &) const
 
- Protected Member Functions inherited from QwtPlotAbstractBarChart
double sampleWidth (const QwtScaleMap &map, double canvasSize, double dataSize, double value) 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.
 

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()

Member Enumeration Documentation

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()

Constructor & Destructor Documentation

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

Constructor

Parameters
titleTitle of the curve
QwtPlotBarChart::QwtPlotBarChart ( const QwtText title)
explicit

Constructor

Parameters
titleTitle of the curve

Member Function Documentation

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

Reimplemented from QwtPlotSeriesItem.

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

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.

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

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.

QwtGraphic QwtPlotBarChart::legendIcon ( int  index,
const QSizeF &  size 
) const
protectedvirtual
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.

QwtPlotBarChart::LegendMode QwtPlotBarChart::legendMode ( ) const
Returns
Legend mode
See also
setLegendMode()
int QwtPlotBarChart::rtti ( ) const
virtual
Returns
QwtPlotItem::Rtti_PlotBarChart

Reimplemented from QwtPlotItem.

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