Provided by: libqwt-doc_6.1.4-2_all 
NAME
QwtSymbol - A class for drawing symbols.
SYNOPSIS
#include <qwt_symbol.h>
Public Types
enum Style { NoSymbol = -1, Ellipse, Rect, Diamond, Triangle, DTriangle, UTriangle,
LTriangle, RTriangle, Cross, XCross, HLine, VLine, Star1, Star2, Hexagon, Path,
Pixmap, Graphic, SvgDocument, UserStyle = 1000 }
enum CachePolicy { NoCache, Cache, AutoCache }
Public Member Functions
QwtSymbol (Style=NoSymbol)
QwtSymbol (Style, const QBrush &, const QPen &, const QSize &)
Constructor.
QwtSymbol (const QPainterPath &, const QBrush &, const QPen &)
Constructor.
virtual ~QwtSymbol ()
Destructor.
void setCachePolicy (CachePolicy)
CachePolicy cachePolicy () const
void setSize (const QSize &)
void setSize (int width, int height=-1)
Specify the symbol's size.
const QSize & size () const
void setPinPoint (const QPointF &pos, bool enable=true)
Set and enable a pin point.
QPointF pinPoint () const
void setPinPointEnabled (bool)
bool isPinPointEnabled () const
virtual void setColor (const QColor &)
Set the color of the symbol.
void setBrush (const QBrush &)
Assign a brush.
const QBrush & brush () const
void setPen (const QColor &, qreal width=0.0, Qt::PenStyle=Qt::SolidLine)
void setPen (const QPen &)
const QPen & pen () const
void setStyle (Style)
Style style () const
void setPath (const QPainterPath &)
Set a painter path as symbol.
const QPainterPath & path () const
void setPixmap (const QPixmap &)
const QPixmap & pixmap () const
void setGraphic (const QwtGraphic &)
const QwtGraphic & graphic () const
void setSvgDocument (const QByteArray &)
void drawSymbol (QPainter *, const QRectF &) const
Draw the symbol into a rectangle.
void drawSymbol (QPainter *, const QPointF &) const
Draw the symbol at a specified position.
void drawSymbols (QPainter *, const QPolygonF &) const
Draw symbols at the specified points.
void drawSymbols (QPainter *, const QPointF *, int numPoints) const
virtual QRect boundingRect () const
void invalidateCache ()
Protected Member Functions
virtual void renderSymbols (QPainter *, const QPointF *, int numPoints) const
Detailed Description
A class for drawing symbols.
Member Enumeration Documentation
enum QwtSymbol::CachePolicy
Depending on the render engine and the complexity of the symbol shape it might be faster
to render the symbol to a pixmap and to paint this pixmap.
F.e. the raster paint engine is a pure software renderer where in cache mode a draw
operation usually ends in raster operation with the the backing store, that are usually
faster, than the algorithms for rendering polygons. But the opposite can be expected for
graphic pipelines that can make use of hardware acceleration.
The default setting is AutoCache
See also:
setCachePolicy(), cachePolicy()
Note:
The policy has no effect, when the symbol is painted to a vector graphics format (
PDF, SVG ).
Warning:
Since Qt 4.8 raster is the default backend on X11
Enumerator
NoCache
Don't use a pixmap cache.
Cache Always use a pixmap cache.
AutoCache
Use a cache when one of the following conditions is true:
• The symbol is rendered with the software renderer ( QPaintEngine::Raster )
enum QwtSymbol::Style
Symbol Style
See also:
setStyle(), style()
Enumerator
NoSymbol
No Style. The symbol cannot be drawn.
Ellipse
Ellipse or circle.
Rect Rectangle.
Diamond
Diamond.
Triangle
Triangle pointing upwards.
DTriangle
Triangle pointing downwards.
UTriangle
Triangle pointing upwards.
LTriangle
Triangle pointing left.
RTriangle
Triangle pointing right.
Cross Cross (+)
XCross Diagonal cross (X)
HLine Horizontal line.
VLine Vertical line.
Star1 X combined with +.
Star2 Six-pointed star.
Hexagon
Hexagon.
Path The symbol is represented by a painter path, where the origin ( 0, 0 ) of the path
coordinate system is mapped to the position of the symbol.
See also:
setPath(), path()
Pixmap The symbol is represented by a pixmap. The pixmap is centered or aligned to its pin
point.
See also:
setPinPoint()
Graphic
The symbol is represented by a graphic. The graphic is centered or aligned to its
pin point.
See also:
setPinPoint()
SvgDocument
The symbol is represented by a SVG graphic. The graphic is centered or aligned to
its pin point.
See also:
setPinPoint()
UserStyle
Styles >= QwtSymbol::UserSymbol are reserved for derived classes of QwtSymbol that
overload drawSymbols() with additional application specific symbol types.
Constructor & Destructor Documentation
QwtSymbol::QwtSymbol (Style style = NoSymbol)
Default Constructor
Parameters:
style Symbol Style
The symbol is constructed with gray interior, black outline with zero width, no size and
style 'NoSymbol'.
QwtSymbol::QwtSymbol (QwtSymbol::Style style, const QBrush & brush, const QPen & pen, const
QSize & size)
Constructor.
Parameters:
style Symbol Style
brush brush to fill the interior
pen outline pen
size size
See also:
setStyle(), setBrush(), setPen(), setSize()
QwtSymbol::QwtSymbol (const QPainterPath & path, const QBrush & brush, const QPen & pen)
Constructor. The symbol gets initialized by a painter path. The style is set to
QwtSymbol::Path, the size is set to empty ( the path is displayed unscaled ).
Parameters:
path painter path
brush brush to fill the interior
pen outline pen
See also:
setPath(), setBrush(), setPen(), setSize()
Member Function Documentation
QRect QwtSymbol::boundingRect () const [virtual]
Calculate the bounding rectangle for a symbol at position (0,0).
Returns:
Bounding rectangle
const QBrush & QwtSymbol::brush () const
Returns:
Brush
See also:
setBrush()
QwtSymbol::CachePolicy QwtSymbol::cachePolicy () const
Returns:
Cache policy
See also:
CachePolicy, setCachePolicy()
void QwtSymbol::drawSymbol (QPainter * painter, const QRectF & rect) const
Draw the symbol into a rectangle. The symbol is painted centered and scaled into the
target rectangle. It is always painted uncached and the pin point is ignored.
This method is primarily intended for drawing a symbol to the legend.
Parameters:
painter Painter
rect Target rectangle for the symbol
void QwtSymbol::drawSymbol (QPainter * painter, const QPointF & pos) const [inline]
Draw the symbol at a specified position.
Parameters:
painter Painter
pos Position of the symbol in screen coordinates
void QwtSymbol::drawSymbols (QPainter * painter, const QPolygonF & points) const [inline]
Draw symbols at the specified points.
Parameters:
painter Painter
points Positions of the symbols in screen coordinates
void QwtSymbol::drawSymbols (QPainter * painter, const QPointF * points, int numPoints) const
Render an array of symbols
Painting several symbols is more effective than drawing symbols one by one, as a couple of
layout calculations and setting of pen/brush can be done once for the complete array.
Parameters:
painter Painter
points Array of points
numPoints Number of points
const QwtGraphic & QwtSymbol::graphic () const
Returns:
Assigned graphic
See also:
setGraphic()
void QwtSymbol::invalidateCache ()
Invalidate the cached symbol pixmap
The symbol invalidates its cache, whenever an attribute is changed that has an effect ob
how to display a symbol. In case of derived classes with individual styles ( >=
QwtSymbol::UserStyle ) it might be necessary to call invalidateCache() for attributes that
are relevant for this style.
See also:
CachePolicy, setCachePolicy(), drawSymbols()
bool QwtSymbol::isPinPointEnabled () const
Returns:
True, when the pin point translation is enabled
See also:
setPinPoint(), setPinPointEnabled()
const QPainterPath & QwtSymbol::path () const
Returns:
Painter path for displaying the symbol
See also:
setPath()
const QPen & QwtSymbol::pen () const
Returns:
Pen
See also:
setPen(), brush()
QPointF QwtSymbol::pinPoint () const
Returns:
Pin point
See also:
setPinPoint(), setPinPointEnabled()
const QPixmap & QwtSymbol::pixmap () const
Returns:
Assigned pixmap
See also:
setPixmap()
void QwtSymbol::renderSymbols (QPainter * painter, const QPointF * points, int numPoints)
const [protected], [virtual]
Render the symbol to series of points
Parameters:
painter Qt painter
points Positions of the symbols
numPoints Number of points
void QwtSymbol::setBrush (const QBrush & brush)
Assign a brush. The brush is used to draw the interior of the symbol.
Parameters:
brush Brush
See also:
brush()
void QwtSymbol::setCachePolicy (QwtSymbol::CachePolicy policy)
Change the cache policy
The default policy is AutoCache
Parameters:
policy Cache policy
See also:
CachePolicy, cachePolicy()
void QwtSymbol::setColor (const QColor & color) [virtual]
Set the color of the symbol. Change the color of the brush for symbol types with a filled
area. For all other symbol types the color will be assigned to the pen.
Parameters:
color Color
See also:
setBrush(), setPen(), brush(), pen()
void QwtSymbol::setGraphic (const QwtGraphic & graphic)
Set a graphic as symbol
Parameters:
graphic Graphic
See also:
graphic(), setPixmap()
Note:
the style() is set to QwtSymbol::Graphic
brush() and pen() have no effect
void QwtSymbol::setPath (const QPainterPath & path)
Set a painter path as symbol. The symbol is represented by a painter path, where the
origin ( 0, 0 ) of the path coordinate system is mapped to the position of the symbol.
When the symbol has valid size the painter path gets scaled to fit into the size.
Otherwise the symbol size depends on the bounding rectangle of the path.
Example
The following code defines a symbol drawing an arrow:
#include <qwt_symbol.h>
QwtSymbol *symbol = new QwtSymbol();
QPen pen( Qt::black, 2 );
pen.setJoinStyle( Qt::MiterJoin );
symbol->setPen( pen );
symbol->setBrush( Qt::red );
QPainterPath path;
path.moveTo( 0, 8 );
path.lineTo( 0, 5 );
path.lineTo( -3, 5 );
path.lineTo( 0, 0 );
path.lineTo( 3, 5 );
path.lineTo( 0, 5 );
QTransform transform;
transform.rotate( -30.0 );
path = transform.map( path );
symbol->setPath( path );
symbol->setPinPoint( QPointF( 0.0, 0.0 ) );
setSize( 10, 14 );
Parameters:
path Painter path
Note:
The style is implicitely set to QwtSymbol::Path.
See also:
path(), setSize()
void QwtSymbol::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()
void QwtSymbol::setPen (const QPen & pen)
Assign a pen
The pen is used to draw the symbol's outline.
Parameters:
pen Pen
See also:
pen(), setBrush()
void QwtSymbol::setPinPoint (const QPointF & pos, bool enable = true)
Set and enable a pin point. The position of a complex symbol is not always aligned to its
center ( f.e an arrow, where the peak points to a position ). The pin point defines the
position inside of a Pixmap, Graphic, SvgDocument or PainterPath symbol where the
represented point has to be aligned to.
Parameters:
pos Position
enable En/Disable the pin point alignment
See also:
pinPoint(), setPinPointEnabled()
void QwtSymbol::setPinPointEnabled (bool on)
En/Disable the pin point alignment
Parameters:
on Enabled, when on is true
See also:
setPinPoint(), isPinPointEnabled()
void QwtSymbol::setPixmap (const QPixmap & pixmap)
Set a pixmap as symbol
Parameters:
pixmap Pixmap
See also:
pixmap(), setGraphic()
Note:
the style() is set to QwtSymbol::Pixmap
brush() and pen() have no effect
void QwtSymbol::setSize (const QSize & size)
Set the symbol's size
Parameters:
size Size
See also:
size()
void QwtSymbol::setSize (int width, int height = -1)
Specify the symbol's size. If the 'h' parameter is left out or less than 0, and the 'w'
parameter is greater than or equal to 0, the symbol size will be set to (w,w).
Parameters:
width Width
height Height (defaults to -1)
See also:
size()
void QwtSymbol::setStyle (QwtSymbol::Style style)
Specify the symbol style
Parameters:
style Style
See also:
style()
void QwtSymbol::setSvgDocument (const QByteArray & svgDocument)
Set a SVG icon as symbol
Parameters:
svgDocument SVG icon
See also:
setGraphic(), setPixmap()
Note:
the style() is set to QwtSymbol::SvgDocument
brush() and pen() have no effect
const QSize & QwtSymbol::size () const
Returns:
Size
See also:
setSize()
QwtSymbol::Style QwtSymbol::style () const
Returns:
Current symbol style
See also:
setStyle()
Author
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