QwtPlotBarChart - Man Page
QwtPlotBarChart displays a series of a values as bars.
Synopsis
#include <qwt_plot_barchart.h>
Inherits QwtPlotAbstractBarChart, and QwtSeriesStore< QPointF >.
Public Types
enum LegendMode { LegendChartTitle, LegendBarTitles }
Legend modes.
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.
const QwtColumnSymbol * symbol () 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 QwtColumnSymbol * specialSymbol (int sampleIndex, const QPointF &) const
virtual QwtText barTitle (int sampleIndex) const
Return the title of a bar.
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< QwtLegendData > legendData () const override
Return all information, that is needed to represent the item on the legend.
QwtGraphic legendIcon (int index, const QSizeF &) const override
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
enum QwtPlotBarChart::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::QwtPlotBarChart (const QString & title = QString()) [explicit]
Constructor
- Parameters
title Title of the curve
Definition at line 51 of file qwt_plot_barchart.cpp.
QwtPlotBarChart::QwtPlotBarChart (const QwtText & title) [explicit]
Constructor
- Parameters
title Title of the curve
Definition at line 41 of file qwt_plot_barchart.cpp.
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
sampleIndex Index of the bar
- Returns
An empty text
- See also
LegendBarTitles
Definition at line 399 of file qwt_plot_barchart.cpp.
QRectF QwtPlotBarChart::boundingRect () const [override], [virtual]
- 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.
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
xMap x map
yMap y map
canvasRect Contents rect of the canvas
boundingInterval Bounding interval of sample values
sample Value of the sample- Returns
Geometry of the column
Definition at line 262 of file qwt_plot_barchart.cpp.
void QwtPlotBarChart::drawBar (QPainter * painter, int sampleIndex, const QPointF & sample, const QwtColumnRect & rect) const [protected], [virtual]
Draw a bar
- Parameters
painter Painter
sampleIndex Index of the sample represented by the bar
sample Value of the sample
rect Bounding rectangle of the bar
Definition at line 341 of file qwt_plot_barchart.cpp.
void QwtPlotBarChart::drawSample (QPainter * painter, const QwtScaleMap & xMap, const QwtScaleMap & yMap, const QRectF & canvasRect, const QwtInterval & boundingInterval, int index, const QPointF & sample) const [protected], [virtual]
Draw a sample
- Parameters
painter Painter
xMap x map
yMap y map
canvasRect Contents rect of the canvas
boundingInterval Bounding interval of sample values
index Index of the sample
sample Value of the sample- See also
drawSeries()
Definition at line 322 of file qwt_plot_barchart.cpp.
void QwtPlotBarChart::drawSeries (QPainter * painter, const QwtScaleMap & xMap, const QwtScaleMap & yMap, const QRectF & canvasRect, int from, int to) const [override], [virtual]
Draw an interval of the bar chart
- Parameters
painter Painter
xMap Maps x-values into pixel coordinates.
yMap Maps y-values into pixel coordinates.
canvasRect Contents rect of the canvas
from Index of the first point to be painted
to Index 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.
QList< QwtLegendData > QwtPlotBarChart::legendData () const [override], [protected], [virtual]
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.
QwtGraphic QwtPlotBarChart::legendIcon (int index, const QSizeF & size) const [override], [protected], [virtual]
- 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
index Index of the legend entry
size Icon size- See also
setLegendMode(), drawBar(), QwtPlotItem::setLegendIconSize(), QwtPlotItem::legendData()
Reimplemented from QwtPlotItem.
Definition at line 462 of file qwt_plot_barchart.cpp.
QwtPlotBarChart::LegendMode QwtPlotBarChart::legendMode () const
- Returns
Legend mode
- See also
setLegendMode()
Definition at line 177 of file qwt_plot_barchart.cpp.
int QwtPlotBarChart::rtti () const [override], [virtual]
- Returns
QwtPlotItem::Rtti_PlotBarChart
Reimplemented from QwtPlotItem.
Definition at line 70 of file qwt_plot_barchart.cpp.
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
mode New mode
- See also
legendMode(), legendData(), barTitle(), QwtPlotItem::ItemAttribute
Definition at line 164 of file qwt_plot_barchart.cpp.
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
samples Vector of y coordinates
- Note
QVector is implicitly shared
Definition at line 97 of file qwt_plot_barchart.cpp.
void QwtPlotBarChart::setSamples (const QVector< QPointF > & samples)
Initialize data with an array of points
- Parameters
samples Vector of points
- Note
QVector is implicitly shared
QPolygonF is derived from QVector<QPointF>
Definition at line 82 of file qwt_plot_barchart.cpp.
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
data Data
- 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.
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
symbol Symbol
- See also
symbol()
Definition at line 134 of file qwt_plot_barchart.cpp.
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
sampleIndex Index of the sample represented by the bar
sample Value of the sample- Returns
NULL, indicating to use the default symbol
Definition at line 377 of file qwt_plot_barchart.cpp.
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.
Author
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