QwtPlotShapeItem(3)            Qwt User's Guide            QwtPlotShapeItem(3)

NAME
       QwtPlotShapeItem - A plot item, which displays any graphical shape,
       that can be defined by a QPainterPath.


SYNOPSIS
       #include <qwt_plot_shapeitem.h>

       Inherits QwtPlotItem.

   Public Types
       enum PaintAttribute { ClipPolygons = 0x01 }
       enum LegendMode { LegendShape, LegendColor }
           Mode how to display the item on the legend.
       typedef QFlags< PaintAttribute > PaintAttributes

   Public Member Functions
       QwtPlotShapeItem (const QString &title=QString())
           Constructor.
       QwtPlotShapeItem (const QwtText &title)
           Constructor.
       virtual ~QwtPlotShapeItem ()
           Destructor.
       void setPaintAttribute (PaintAttribute, bool on=true)
       bool testPaintAttribute (PaintAttribute) const
       void setLegendMode (LegendMode)
       LegendMode legendMode () const
       void setRect (const QRectF &)
           Set a path built from a rectangle.
       void setPolygon (const QPolygonF &)
           Set a path built from a polygon.
       void setShape (const QPainterPath &)
           Set the shape to be displayed.
       QPainterPath shape () const
       void setPen (const QColor &, qreal width=0.0,
           Qt::PenStyle=Qt::SolidLine)
       void setPen (const QPen &)
           Assign a pen.
       QPen pen () const
       void setBrush (const QBrush &)
       QBrush brush () const
       void setRenderTolerance (double)
           Set the tolerance for the weeding optimization.
       double renderTolerance () const
       virtual QRectF boundingRect () const override
           Bounding rectangle of the shape.
       virtual void draw (QPainter *, const QwtScaleMap &xMap, const
           QwtScaleMap &yMap, const QRectF &canvasRect) const override
       virtual QwtGraphic legendIcon (int index, const QSizeF &) const
           override
       virtual int rtti () const override

   Additional Inherited Members

Detailed Description
       A plot item, which displays any graphical shape, that can be defined by
       a QPainterPath.

       A QPainterPath is a shape composed from intersecting and uniting
       regions, rectangles, ellipses or irregular areas defined by lines, and
       curves. QwtPlotShapeItem displays a shape with a pen and brush.

       QwtPlotShapeItem offers a couple of optimizations like clipping or
       weeding. These algorithms need to convert the painter path into
       polygons that might be less performant for paths built from curves and
       ellipses.

       More complex shapes, that can't be expressed by a QPainterPath can be
       displayed using QwtPlotGraphicItem.

       See also
           QwtPlotZone, QwtPlotGraphicItem

       Definition at line 38 of file qwt_plot_shapeitem.h.

Member Typedef Documentation
   typedef QFlags<PaintAttribute > QwtPlotShapeItem::PaintAttributes
       An ORed combination of PaintAttribute values.

       Definition at line 61 of file qwt_plot_shapeitem.h.

Member Enumeration Documentation
   enum QwtPlotShapeItem::LegendMode
       Mode how to display the item on the legend.

       Enumerator

       LegendShape
              Display a scaled down version of the shape.

       LegendColor
              Display a filled rectangle.

       Definition at line 64 of file qwt_plot_shapeitem.h.

   enum QwtPlotShapeItem::PaintAttribute
       Attributes to modify the drawing algorithm. The default disables all
       attributes

       See also
           setPaintAttribute(), testPaintAttribute()

       Enumerator

       ClipPolygons
              Clip polygons before painting them. In situations, where points
              are far outside the visible area (f.e when zooming deep) this
              might be a substantial improvement for the painting performance

       But polygon clipping will convert the painter path into polygons what
       might introduce a negative impact on the performance of paths composed
       from curves or ellipses.

       Definition at line 47 of file qwt_plot_shapeitem.h.

Constructor & Destructor Documentation
   QwtPlotShapeItem::QwtPlotShapeItem (const QString & title = QString())
       [explicit]
       Constructor. Sets the following item attributes:

       o QwtPlotItem::AutoScale: true

       o QwtPlotItem::Legend: false

       Parameters
           title Title

       Definition at line 112 of file qwt_plot_shapeitem.cpp.

   QwtPlotShapeItem::QwtPlotShapeItem (const QwtText & title) [explicit]
       Constructor. Sets the following item attributes:

       o QwtPlotItem::AutoScale: true

       o QwtPlotItem::Legend: false

       Parameters
           title Title

       Definition at line 127 of file qwt_plot_shapeitem.cpp.

Member Function Documentation
   QBrush QwtPlotShapeItem::brush () const
       Returns
           Brush used to fill the shape

       See also
           setBrush(), pen()

       Definition at line 336 of file qwt_plot_shapeitem.cpp.

   void QwtPlotShapeItem::draw (QPainter * painter, const QwtScaleMap & xMap,
       const QwtScaleMap & yMap, const QRectF & canvasRect) const [override],
       [virtual]
       Draw the shape item

       Parameters
           painter Painter
           xMap X-Scale Map
           yMap Y-Scale Map
           canvasRect Contents rect of the plot canvas

       Implements QwtPlotItem.

       Definition at line 385 of file qwt_plot_shapeitem.cpp.

   QwtGraphic QwtPlotShapeItem::legendIcon (int index, const QSizeF & size)
       const [override],  [virtual]
       Returns
           A rectangle filled with the color of the brush ( or the pen )

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

       See also
           setLegendIconSize(), legendData()

       Reimplemented from QwtPlotItem.

       Definition at line 463 of file qwt_plot_shapeitem.cpp.

   QwtPlotShapeItem::LegendMode QwtPlotShapeItem::legendMode () const
       Returns
           Mode how to represent the item on the legend

       See also
           legendMode()

       Definition at line 199 of file qwt_plot_shapeitem.cpp.

   QPen QwtPlotShapeItem::pen () const
       Returns
           Pen used to draw the outline of the shape

       See also
           setPen(), brush()

       Definition at line 310 of file qwt_plot_shapeitem.cpp.

   double QwtPlotShapeItem::renderTolerance () const
       Returns
           Tolerance for the weeding optimization

       See also
           setRenderTolerance()

       Definition at line 372 of file qwt_plot_shapeitem.cpp.

   int QwtPlotShapeItem::rtti () const [override],  [virtual]
       Returns
           QwtPlotItem::Rtti_PlotShape

       Reimplemented from QwtPlotItem.

       Definition at line 151 of file qwt_plot_shapeitem.cpp.

   void QwtPlotShapeItem::setBrush (const QBrush & brush)
       Assign a brush.

       The brush is used to fill the path

       Parameters
           brush Brush

       See also
           brush(), pen()

       Definition at line 323 of file qwt_plot_shapeitem.cpp.

   void QwtPlotShapeItem::setLegendMode (LegendMode mode)
       Set the mode how to represent the item on the legend

       Parameters
           mode Mode

       See also
           legendMode()

       Definition at line 186 of file qwt_plot_shapeitem.cpp.

   void QwtPlotShapeItem::setPaintAttribute (PaintAttribute attribute, bool on
       = true)
       Specify an attribute how to draw the shape

       Parameters
           attribute Paint attribute
           on On/Off

       See also
           testPaintAttribute()

       Definition at line 163 of file qwt_plot_shapeitem.cpp.

   void QwtPlotShapeItem::setPen (const QColor & color, qreal width = 0.0,
       Qt::PenStyle style = Qt::SolidLine)
       Build and assign a pen

       In Qt5 the default pen width is 1.0 ( 0.0 in Qt4 ) what makes it non
       cosmetic ( see QPen::isCosmetic() ). This method has been introduced to
       hide this incompatibility.

       Parameters
           color Pen color
           width Pen width
           style Pen style

       See also
           pen(), brush()

       Definition at line 284 of file qwt_plot_shapeitem.cpp.

   void QwtPlotShapeItem::setPen (const QPen & pen)
       Assign a pen. The pen is used to draw the outline of the shape

       Parameters
           pen Pen

       See also
           pen(), brush()

       Definition at line 297 of file qwt_plot_shapeitem.cpp.

   void QwtPlotShapeItem::setPolygon (const QPolygonF & polygon)
       Set a path built from a polygon.

       Parameters
           polygon Polygon

       See also
           setShape(), setRect(), shape()

       Definition at line 230 of file qwt_plot_shapeitem.cpp.

   void QwtPlotShapeItem::setRect (const QRectF & rect)
       Set a path built from a rectangle.

       Parameters
           rect Rectangle

       See also
           setShape(), setPolygon(), shape()

       Definition at line 216 of file qwt_plot_shapeitem.cpp.

   void QwtPlotShapeItem::setRenderTolerance (double tolerance)
       Set the tolerance for the weeding optimization. After translating the
       shape into target device coordinate ( usually widget geometries ) the
       painter path can be simplified by a point weeding algorithm ( Douglas-
       Peucker ).

       For shapes built from curves and ellipses weeding might have the
       opposite effect because they have to be expanded to polygons.

       Parameters
           tolerance Accepted error when reducing the number of points A value
           <= 0.0 disables weeding.

       See also
           renderTolerance(), QwtWeedingCurveFitter

       Definition at line 357 of file qwt_plot_shapeitem.cpp.

   void QwtPlotShapeItem::setShape (const QPainterPath & shape)
       Set the shape to be displayed.

       Parameters
           shape Shape

       See also
           setShape(), shape()

       Definition at line 244 of file qwt_plot_shapeitem.cpp.

   QPainterPath QwtPlotShapeItem::shape () const
       Returns
           Shape to be displayed

       See also
           setShape()

       Definition at line 266 of file qwt_plot_shapeitem.cpp.

   bool QwtPlotShapeItem::testPaintAttribute (PaintAttribute attribute) const
       Returns
           True, when attribute is enabled

       See also
           setPaintAttribute()

       Definition at line 175 of file qwt_plot_shapeitem.cpp.


Author
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Version 6.2.0                   Sun Jul 18 2021            QwtPlotShapeItem(3)