QwtPlotItem - Base class for items on the plot canvas.

       Generated automatically by Doxygen for Qwt User's Guide from the source code.

Version 6.1.4                                    Wed Jan 2 2019                                   QwtPlotItem(3)

QwtPlotItem::QwtPlotItem(constQwtText&title=QwtText())[explicit]
       Constructor

       Parameters:title Title of the item

       Base class for items on the plot canvas.

       A plot item is 'something', that can be painted on the plot canvas, or only affects the scales of the
       plot widget. They can be categorized as:

       • Representator
          A  'Representator'  is  an  item  that  represents some sort of data on the plot canvas. The different
         representator classes are organized according to the characteristics of the data:

         • QwtPlotMarker Represents a point or a horizontal/vertical coordinate

         • QwtPlotCurve Represents a series of points

         • QwtPlotSpectrogram ( QwtPlotRasterItem ) Represents raster data

         • ...

       • Decorators
          A 'Decorator' is an item, that displays additional information, that is not related to any data:

         • QwtPlotGrid

         • QwtPlotScaleItem

         • QwtPlotSvgItem

         • ...

       Depending on the QwtPlotItem::ItemAttribute flags, an item is included into autoscaling or has  an  entry
       on the legend.

       Before misusing the existing item classes it might be better to implement a new type of plot item ( don't
       implement  a  watermark as spectrogram ). Deriving a new type of QwtPlotItem primarily means to implement
       the YourPlotItem::draw() method.

       Seealso:
           The cpuplot example shows the implementation of additional plot items.

enumQwtPlotItem::ItemAttribute
       Plot Item Attributes. Various aspects of a plot widget depend on the  attributes  of  the  attached  plot
       items. If and how a single plot item participates in these updates depends on its attributes.

       Seealso:setItemAttribute(), testItemAttribute(), ItemInterestEnumeratorLegend The item is represented on the legend.

       AutoScale
              The  boundingRect() of the item is included in the autoscaling calculation as long as its width or
              height is >= 0.0.

       Margins
              The item needs extra space to display something outside its bounding rectangle.

       Seealso:getCanvasMarginHint()enumQwtPlotItem::ItemInterest
       Plot Item Interests. Plot items might depend on the  situation  of  the  corresponding  plot  widget.  By
       enabling an interest the plot item will be notified, when the corresponding attribute of the plot widgets
       has changed.

       Seealso:setItemAttribute(), testItemAttribute(), ItemInterestEnumeratorScaleInterest
              The item is interested in updates of the scales

       Seealso:updateScaleDiv()LegendInterest
              The  item  is  interested  in  updates  of the legend ( of other items ) This flag is intended for
              items, that want to implement a legend for displaying entries of other plot item.

       Note:
           If the plot item wants to be represented on a legend enable QwtPlotItem::Legend instead.

       Seealso:updateLegend()enumQwtPlotItem::RenderHint
       Render hints.

       EnumeratorRenderAntialiased
              Enable antialiasing.

   enumQwtPlotItem::RttiValues
       Runtime type information. RttiValues is used to cast plot items, without having to  enable  runtime  type
       information of the compiler.

       EnumeratorRtti_PlotItem
              Unspecific value, that can be used, when it doesn't matter.

       Rtti_PlotGrid
              For QwtPlotGrid.

       Rtti_PlotScale
              For QwtPlotScaleItem.

       Rtti_PlotLegend
              For QwtPlotLegendItem.

       Rtti_PlotMarker
              For QwtPlotMarker.

       Rtti_PlotCurve
              For QwtPlotCurve.

       Rtti_PlotSpectroCurve
              For QwtPlotSpectroCurve.

       Rtti_PlotIntervalCurve
              For QwtPlotIntervalCurve.

       Rtti_PlotHistogram
              For QwtPlotHistogram.

       Rtti_PlotSpectrogram
              For QwtPlotSpectrogram.

       Rtti_PlotSVG
              For QwtPlotSvgItem.

       Rtti_PlotTradingCurve
              For QwtPlotTradingCurve.

       Rtti_PlotBarChart
              For QwtPlotBarChart.

       Rtti_PlotMultiBarChart
              For QwtPlotMultiBarChart.

       Rtti_PlotShape
              For QwtPlotShapeItem.

       Rtti_PlotTextLabel
              For QwtPlotTextLabel.

       Rtti_PlotZone
              For QwtPlotZoneItem.

       Rtti_PlotUserItem
              Values >= Rtti_PlotUserItem are reserved for plot items not implemented in the Qwt library.

voidQwtPlotItem::attach(QwtPlot*plot)
       Attach  the  item to a plot. This method will attach a QwtPlotItem to the QwtPlot argument. It will first
       detach the QwtPlotItem from any plot from a previous call to attach (if necessary). If a NULL argument is
       passed, it will detach from any QwtPlot it was attached to.

       Parameters:plot Plot widget

       Seealso:detach()QRectFQwtPlotItem::boundingRect()const[virtual]Returns:
           An invalid bounding rect: QRectF(1.0, 1.0, -2.0, -2.0)

       Note:
           A width or height < 0.0 is ignored by the autoscaler

       Reimplemented   in   QwtPlotTradingCurve,    QwtPlotMarker,    QwtPlotIntervalCurve,    QwtPlotHistogram,
       QwtPlotRasterItem,     QwtPlotShapeItem,    QwtPlotBarChart,    QwtPlotMultiBarChart,    QwtPlotZoneItem,
       QwtPlotSeriesItem, and QwtPlotSvgItem.

   QwtGraphicQwtPlotItem::defaultIcon(constQBrush&brush,constQSizeF&size)const[protected]
       Return a default icon from a brush. The default icon is  a  filled  rectangle  used  in  several  derived
       classes as legendIcon().

       Parameters:brush Fill brush
           size Icon size

       Returns:
           A filled rectangle

   voidQwtPlotItem::detach()
       This  method  detaches a QwtPlotItem from any QwtPlot it has been associated with. detach() is equivalent
       to calling attach( NULL )

       Seealso:attach()virtualvoidQwtPlotItem::draw(QPainter*painter,constQwtScaleMap&xMap,constQwtScaleMap&yMap,constQRectF&canvasRect)const[purevirtual]
       Draw the item.

       Parameters:painter Painter
           xMap Maps x-values into pixel coordinates.
           yMap Maps y-values into pixel coordinates.
           canvasRect Contents rect of the canvas in painter coordinates

       Implemented in QwtPlotMarker, QwtPlotLegendItem, QwtPlotRasterItem, QwtPlotShapeItem, QwtPlotSpectrogram,
       QwtPlotScaleItem, QwtPlotGrid, QwtPlotTextLabel, QwtPlotZoneItem, QwtPlotSvgItem, and QwtPlotSeriesItem.

   voidQwtPlotItem::getCanvasMarginHint(constQwtScaleMap&xMap,constQwtScaleMap&yMap,constQRectF&canvasRect,double&left,double&top,double&right,double&bottom)const[virtual]
       Calculate  a  hint  for  the  canvas  margin. When the QwtPlotItem::Margins flag is enabled the plot item
       indicates, that it needs some margins at the borders of the canvas. This is f.e. used by  bar  charts  to
       reserve space for displaying the bars.

       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

       The default implementation returns 0 for all margins

       Seealso:QwtPlot::getCanvasMarginsHint(), QwtPlot::updateCanvasMargins()

       Reimplemented in QwtPlotAbstractBarChart.

   boolQwtPlotItem::isVisible()constReturns:
           true if visible

       Seealso:setVisible(), show(), hide()voidQwtPlotItem::itemChanged()[virtual]
       Update the legend and call QwtPlot::autoRefresh() for the parent plot.

       Seealso:
           QwtPlot::legendChanged(), QwtPlot::autoRefresh()voidQwtPlotItem::legendChanged()[virtual]
       Update the legend of the parent plot.

       Seealso:QwtPlot::updateLegend(), itemChanged()QList<QwtLegendData>QwtPlotItem::legendData()const[virtual]
       Return all information, that is needed to represent the item on the legend. Most items are represented by
       one  entry on the legend showing an icon and a text, but f.e. QwtPlotMultiBarChart displays one entry for
       each bar.

       QwtLegendData is basically a list of QVariants  that  makes  it  possible  to  overload  and  reimplement
       legendData()  to  return  almost any type of information, that is understood by the receiver that acts as
       the legend.

       The default implementation returns one entry with the title() of the item and the legendIcon().

       Returns:
           Data, that is needed to represent the item on the legend

       Seealso:title(), legendIcon(), QwtLegend, QwtPlotLegendItem

       Reimplemented in QwtPlotBarChart, and QwtPlotMultiBarChart.

   QwtGraphicQwtPlotItem::legendIcon(intindex,constQSizeF&size)const[virtual]Returns:
           Icon representing the item on the legend

       The default implementation returns an invalid icon

       Parameters:index Index of the legend entry ( usually there is only one )
           size Icon size

       Seealso:setLegendIconSize(), legendData()

       Reimplemented    in    QwtPlotCurve,    QwtPlotTradingCurve,     QwtPlotMarker,     QwtPlotIntervalCurve,
       QwtPlotHistogram, QwtPlotBarChart, QwtPlotShapeItem, and QwtPlotMultiBarChart.

   QSizeQwtPlotItem::legendIconSize()constReturns:
           Legend icon size

       Seealso:setLegendIconSize(), legendIcon()QRectFQwtPlotItem::paintRect(constQwtScaleMap&xMap,constQwtScaleMap&yMap)const
       Calculate the bounding paint rectangle of 2 maps.

       Parameters:xMap Maps x-values into pixel coordinates.
           yMap Maps y-values into pixel coordinates.

       Returns:
           Bounding paint rectangle of the scale maps, not normalized

   uintQwtPlotItem::renderThreadCount()constReturns:
           Number  of  threads  to be used for rendering. If numThreads() is set to 0, the system specific ideal
           thread count is used.

   intQwtPlotItem::rtti()const[virtual]
       Return rtti for the specific class represented. QwtPlotItem is simply a virtual interface class, and base
       classes will implement this method with specific rtti values so a user can differentiate them.

       The rtti value is useful for environments, where the runtime type information is disabled and it  is  not
       possible to do a dynamic_cast<...>.

       Returns:
           rtti value

       Seealso:RttiValues

       Reimplemented     in    QwtPlotCurve,    QwtPlotTradingCurve,    QwtPlotShapeItem,    QwtPlotSpectrogram,
       QwtPlotIntervalCurve,    QwtPlotHistogram,    QwtPlotMarker,    QwtPlotBarChart,    QwtPlotMultiBarChart,
       QwtPlotLegendItem,  QwtPlotScaleItem, QwtPlotTextLabel, QwtPlotSpectroCurve, QwtPlotSvgItem, QwtPlotGrid,
       and QwtPlotZoneItem.

   QRectFQwtPlotItem::scaleRect(constQwtScaleMap&xMap,constQwtScaleMap&yMap)const
       Calculate the bounding scale rectangle of 2 maps.

       Parameters:xMap Maps x-values into pixel coordinates.
           yMap Maps y-values into pixel coordinates.

       Returns:
           Bounding scale rect of the scale maps, not normalized

   voidQwtPlotItem::setAxes(intxAxis,intyAxis)
       Set X and Y axis

       The item will painted according to the coordinates of its Axes.

       Parameters:xAxis X Axis ( QwtPlot::xBottom or QwtPlot::xTop )
           yAxis Y Axis ( QwtPlot::yLeft or QwtPlot::yRight )

       Seealso:setXAxis(), setYAxis(), xAxis(), yAxis(), QwtPlot::AxisvoidQwtPlotItem::setItemAttribute(ItemAttributeattribute,boolon=true)
       Toggle an item attribute

       Parameters:attribute Attribute type
           on true/false

       Seealso:testItemAttribute(), ItemInterestvoidQwtPlotItem::setItemInterest(ItemInterestinterest,boolon=true)
       Toggle an item interest

       Parameters:interest Interest type
           on true/false

       Seealso:testItemInterest(), ItemAttributevoidQwtPlotItem::setLegendIconSize(constQSize&size)
       Set the size of the legend icon

       The default setting is 8x8 pixels

       Parameters:size Size

       Seealso:legendIconSize(), legendIcon()voidQwtPlotItem::setRenderHint(RenderHinthint,boolon=true)
       Toggle an render hint

       Parameters:hint Render hint
           on true/false

       Seealso:testRenderHint(), RenderHintvoidQwtPlotItem::setRenderThreadCount(uintnumThreads)
       On multi core systems rendering of certain plot item ( f.e QwtPlotRasterItem ) can be done in parallel in
       several threads.

       The default setting is set to 1.

       Parameters:numThreads Number of threads to be used for rendering. If numThreads is set to 0, the system specific
           ideal thread count is used.

       The default thread count is 1 ( = no additional threads )

   voidQwtPlotItem::setTitle(constQString&title)
       Set a new title

       Parameters:title Title

       Seealso:title()voidQwtPlotItem::setTitle(constQwtText&title)
       Set a new title

       Parameters:title Title

       Seealso:title()voidQwtPlotItem::setVisible(boolon)[virtual]
       Show/Hide the item

       Parameters:on Show if true, otherwise hide

       Seealso:isVisible(), show(), hide()voidQwtPlotItem::setXAxis(intaxis)
       Set the X axis

       The item will painted according to the coordinates its Axes.

       Parameters:axis X Axis ( QwtPlot::xBottom or QwtPlot::xTop )

       Seealso:setAxes(), setYAxis(), xAxis(), QwtPlot::AxisvoidQwtPlotItem::setYAxis(intaxis)
       Set the Y axis

       The item will painted according to the coordinates its Axes.

       Parameters:axis Y Axis ( QwtPlot::yLeft or QwtPlot::yRight )

       Seealso:setAxes(), setXAxis(), yAxis(), QwtPlot::AxisvoidQwtPlotItem::setZ(doublez)
       Set the z value. Plot items are painted in increasing z-order.

       Parameters:z Z-value

       Seealso:z(), QwtPlotDict::itemList()boolQwtPlotItem::testItemAttribute(ItemAttributeattribute)const
       Test an item attribute

       Parameters:attribute Attribute type

       Returns:
           true/false

       Seealso:setItemAttribute(), ItemInterestboolQwtPlotItem::testItemInterest(ItemInterestinterest)const
       Test an item interest

       Parameters:interest Interest type

       Returns:
           true/false

       Seealso:setItemInterest(), ItemAttributeboolQwtPlotItem::testRenderHint(RenderHinthint)const
       Test a render hint

       Parameters:hint Render hint

       Returns:
           true/false

       Seealso:setRenderHint(), RenderHintconstQwtText&QwtPlotItem::title()constReturns:
           Title of the item

       Seealso:setTitle()voidQwtPlotItem::updateLegend(constQwtPlotItem*item,constQList<QwtLegendData>&data)[virtual]
       Update the item to changes of the legend info. Plot items that want to display a legend ( not those, that
       want to be displayed on a legend ! ) will have to implement updateLegend().

       updateLegend() is only called when the LegendInterest interest is  enabled.  The  default  implementation
       does nothing.

       Parameters:item Plot item to be displayed on a legend
           data Attributes how to display item on the legend

       Seealso:QwtPlotLegendItemNote:
           Plot  items, that want to be displayed on a legend need to enable the QwtPlotItem::Legend flag and to
           implement legendData() and legendIcon()

       Reimplemented in QwtPlotLegendItem.

   voidQwtPlotItem::updateScaleDiv(constQwtScaleDiv&xScaleDiv,constQwtScaleDiv&yScaleDiv)[virtual]
       Update the item to changes of the axes scale division. Update the  item,  when  the  axes  of  plot  have
       changed.  The  default  implementation  does  nothing,  but items that depend on the scale division (like
       QwtPlotGrid()) have to reimplement updateScaleDiv()updateScaleDiv() is only called when the ScaleInterest interest is enabled.  The  default  implementation
       does nothing.

       Parameters:xScaleDiv Scale division of the x-axis
           yScaleDiv Scale division of the y-axis

       Seealso:QwtPlot::updateAxes(), ScaleInterest

       Reimplemented in QwtPlotScaleItem, QwtPlotGrid, and QwtPlotSeriesItem.

   doubleQwtPlotItem::z()const
       Plot items are painted in increasing z-order.

       Returns:setZ(), QwtPlotDict::itemList()

       QwtPlotItem - Base class for items on the plot canvas.

       #include <qwt_plot_item.h>

       Inherited by QwtPlotGrid, QwtPlotLegendItem, QwtPlotMarker, QwtPlotRasterItem, QwtPlotScaleItem,
       QwtPlotSeriesItem, QwtPlotShapeItem, QwtPlotSvgItem, QwtPlotTextLabel, and QwtPlotZoneItem.

   PublicTypes
       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.
       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
           Plot Item Attributes.
       typedef QFlags< ItemInterest > ItemInterests
           Plot Item Interests.
       typedef QFlags< RenderHint > RenderHints
           Render hints.

   PublicMemberFunctionsQwtPlotItem (const QwtText &title=QwtText())
       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 (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 draw (QPainter *painter, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF
           &canvasRect) const =0
           Draw the item.
       virtual QRectF boundingRect () 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.
       virtual void updateScaleDiv (const QwtScaleDiv &, const QwtScaleDiv &)
           Update the item to changes of the axes scale division.
       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 QwtGraphiclegendIcon (int index, const QSizeF &) const

   ProtectedMemberFunctionsQwtGraphicdefaultIcon (const QBrush &, const QSizeF &) const
           Return a default icon from a brush.