Provided by: libqwt-doc_6.1.2-5_all 
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
Paint attributes.
Public Member Functions
QwtPlotShapeItem (const QString &title=QString::null)
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
Bounding rectangle of the shape.
virtual void draw (QPainter *p, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const
QRectF &rect) const
virtual QwtGraphic legendIcon (int index, const QSizeF &) const
virtual int rtti () const
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.
See Also:
QwtPlotZone
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.
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.
Constructor & Destructor Documentation
QwtPlotShapeItem::QwtPlotShapeItem (const QString &title = QString::null) [explicit]
Constructor. Sets the following item attributes:
• QwtPlotItem::AutoScale: true
• QwtPlotItem::Legend: false
Parameters:
title Title
QwtPlotShapeItem::QwtPlotShapeItem (const QwtText &title) [explicit]
Constructor. Sets the following item attributes:
• QwtPlotItem::AutoScale: true
• QwtPlotItem::Legend: false
Parameters:
title Title
Member Function Documentation
QBrush QwtPlotShapeItem::brush () const
Returns:
Brush used to fill the shape
See Also:
setBrush(), pen()
void QwtPlotShapeItem::draw (QPainter *painter, const QwtScaleMap &xMap, const QwtScaleMap
&yMap, const QRectF &canvasRect) const [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.
QwtGraphic QwtPlotShapeItem::legendIcon (intindex, const QSizeF &size) const [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.
QwtPlotShapeItem::LegendMode QwtPlotShapeItem::legendMode () const
Returns:
Mode how to represent the item on the legend
See Also:
legendMode()
QPen QwtPlotShapeItem::pen () const
Returns:
Pen used to draw the outline of the shape
See Also:
setPen(), brush()
double QwtPlotShapeItem::renderTolerance () const
Returns:
Tolerance for the weeding optimization
See Also:
setRenderTolerance()
int QwtPlotShapeItem::rtti () const [virtual]
Returns:
QwtPlotItem::Rtti_PlotShape
Reimplemented from QwtPlotItem.
void QwtPlotShapeItem::setBrush (const QBrush &brush)
Assign a brush.
The brush is used to fill the path
Parameters:
brush Brush
See Also:
brush(), pen()
void QwtPlotShapeItem::setLegendMode (LegendModemode)
Set the mode how to represent the item on the legend
Parameters:
mode Mode
See Also:
legendMode()
void QwtPlotShapeItem::setPaintAttribute (PaintAttributeattribute, boolon = true)
Specify an attribute how to draw the shape
Parameters:
attribute Paint attribute
on On/Off
See Also:
testPaintAttribute()
void QwtPlotShapeItem::setPen (const QColor &color, qrealwidth = 0.0, Qt::PenStylestyle =
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()
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()
void QwtPlotShapeItem::setPolygon (const QPolygonF &polygon)
Set a path built from a polygon.
Parameters:
polygon Polygon
See Also:
setShape(), setRect(), shape()
void QwtPlotShapeItem::setRect (const QRectF &rect)
Set a path built from a rectangle.
Parameters:
rect Rectangle
See Also:
setShape(), setPolygon(), shape()
void QwtPlotShapeItem::setRenderTolerance (doubletolerance)
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
void QwtPlotShapeItem::setShape (const QPainterPath &shape)
Set the shape to be displayed.
Parameters:
shape Shape
See Also:
setShape(), shape()
QPainterPath QwtPlotShapeItem::shape () const
Returns:
Shape to be displayed
See Also:
setShape()
bool QwtPlotShapeItem::testPaintAttribute (PaintAttributeattribute) const
Returns:
True, when attribute is enabled
See Also:
setPaintAttribute()
Author
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