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NAME

       QwtPlotBarChart - 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::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.
       const QwtColumnSymbol * symbol () 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 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 &point, const
           QwtColumnRect &) const
       QList< QwtLegendData > legendData () const
           Return all information, that is needed to represent the item on the legend.
       QwtGraphic legendIcon (int index, const QSizeF &) const

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

   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()

Constructor & Destructor Documentation

   QwtPlotBarChart::QwtPlotBarChart (const QString & title = QString::null) [explicit]
       Constructor

       Parameters:
           title Title of the curve

   QwtPlotBarChart::QwtPlotBarChart (const QwtText & title) [explicit]
       Constructor

       Parameters:
           title Title 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:
           sampleIndex Index 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 [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

   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()

   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:
           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.

   QList< QwtLegendData > QwtPlotBarChart::legendData () const [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.

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

   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:
           mode New mode

       See also:
           legendMode(), legendData(), barTitle(), QwtPlotItem::ItemAttribute

   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>

   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

   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.

   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()

   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

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

       See also:
           setSymbol()

Author

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