---
name: "QwtMarker"
section: "3"
platform: "linux"
package: "libqwt-doc"
version: "4.2.0-6"
release: "Debian 6.0 (Squeeze)"
platforms: ["linux"]
url: "https://new.carta.tech/QwtMarker"
---

# QwtMarker(3)

## NAME

QwtMarker -

## SYNOPSIS

Inherited by **QwtPlotMarker**.

## Detailed Description

A class for drawing markers.

A marker can be a horizontal line, a vertical line, a symbol, a label or any combination of them, which can be drawn around a center point inside a bounding rectangle.

The **QwtMarker::setSymbol()** member assigns a symbol to the marker. The symbol is drawn at the specified point.

With **QwtMarker::setLabel()**, a label can be assigned to the marker. The **QwtMarker::setLabelAlignment()** member specifies where the label is drawn. All the Align\*-constants in Qt::AlignmentFlags (see Qt documentation) are valid. The interpretation of the alignment depends on the marker's line style. The alignment refers to the center point of the marker, which means, for example, that the label would be printed left above the center point if the alignment was set to AlignLeft\|AlignTop.

Definition at line 43 of file qwt\_marker.h.

### Public Types

enum **LineStyle** { **NoLine**, **HLine**, **VLine**, **Cross** }\

### Public Member Functions

**QwtMarker** ()\
 virtual **~QwtMarker** ()\
 **QwtMarker** (const **QwtMarker** &)\
 **QwtMarker** & **operator=** (const **QwtMarker** &)\
 void **setLineStyle** (**LineStyle** st)\
 **LineStyle** **lineStyle** () const\
 void **setSymbol** (const **QwtSymbol** &s)\
 const **QwtSymbol** & **symbol** () const\
 void **setLabel** (const QString &text, const QFont &font=QFont(), const QColor &color=QColor(), const QPen &pen=QPen(Qt::NoPen), const QBrush &brush=QBrush(Qt::NoBrush))\
 void **setLabelText** (const QString &text)\
 const QString **label** () const\
 void **setLabelAlignment** (int align)\
 int **labelAlignment** () const\
 void **setLabelColor** (const QColor &c)\
 const QColor **labelColor** () const\
 void **setLabelPen** (const QPen &p)\
 const QPen **labelPen** () const\
 void **setLinePen** (const QPen &p)\
 const QPen & **linePen** () const\
 void **setFont** (const QFont &f)\
 const QFont **font** () const\
 virtual void **draw** (QPainter \*p, int x, int y, const QRect &r)\

### Protected Member Functions

virtual void **markerChanged** ()\

## Member Enumeration Documentation

### enum QwtMarker::LineStyle

Line styles.

**See also:**

**QwtMarker::setLineStyle**, **QwtMarker::lineStyle**

Definition at line 51 of file qwt\_marker.h.

Referenced by lineStyle().

## Constructor & Destructor Documentation

### QwtMarker::QwtMarker ()

Sets alignment to Qt::AlignCenter, and style to NoLine.

Definition at line 20 of file qwt\_marker.cpp.

References QwtText::makeText().

### QwtMarker::~QwtMarker ()` [virtual]`

Destructor.

Definition at line 29 of file qwt\_marker.cpp.

### QwtMarker::QwtMarker (const QwtMarker & m)

Copy constructor.

**Parameters:**

*m* Marker

Definition at line 38 of file qwt\_marker.cpp.

References QwtText::clone(), d\_align, d\_label, d\_pen, d\_style, and d\_sym.

## Member Function Documentation

### void QwtMarker::draw (QPainter \* p, int x, int y, const QRect & r)` [virtual]`

Draw the marker.

**Parameters:**

*p* Painter \
 *x* X position \
 *y* Y position \
 *r* Bounding rectangle

Definition at line 72 of file qwt\_marker.cpp.

References QwtText::boundingRect(), QwtText::draw(), QwtSymbol::draw(), QwtPainter::drawLine(), QwtPainter::metricsMap(), QwtSymbol::size(), QwtSymbol::style(), and QwtText::text().

Referenced by QwtPlot::drawCanvasItems().

### const QFont QwtMarker::font () const

**Returns:**

the font used for the label

**See also:**

**QwtMarker::setFont()**

Definition at line 189 of file qwt\_marker.cpp.

References QwtText::font().

Referenced by QwtPlotPrintFilter::apply(), and QwtPlot::markerFont().

### const QString QwtMarker::label () const

**Returns:**

the label

**See also:**

**QwtMarker::setLabel()**

Definition at line 282 of file qwt\_marker.cpp.

References QwtText::text().

Referenced by QwtPlot::markerLabel(), and setLabel().

### int QwtMarker::labelAlignment () const

**Returns:**

the label alignment

**See also:**

**QwtMarker::setLabelAlignment()**

Definition at line 311 of file qwt\_marker.cpp.

Referenced by QwtPlot::markerLabelAlign().

### const QColor QwtMarker::labelColor () const

**Returns:**

the label's color

**See also:**

**QwtMarker::setLabelPen()**

Definition at line 357 of file qwt\_marker.cpp.

References QwtText::color().

### const QPen QwtMarker::labelPen () const

**Returns:**

the label's pen

**See also:**

**QwtMarker::setLabelPen()**

**Warning:**

This function is deprecated. Use **QwtMarker::labelColor**.

Definition at line 382 of file qwt\_marker.cpp.

References QwtText::color().

Referenced by QwtPlotPrintFilter::apply(), QwtPlot::markerLabelPen(), and QwtPlotPrintFilter::reset().

### const QPen & QwtMarker::linePen () const

**Returns:**

the line pen

**See also:**

**QwtMarker::setLinePen()**

Definition at line 334 of file qwt\_marker.cpp.

Referenced by QwtPlotPrintFilter::apply(), QwtPlot::markerLinePen(), and QwtPlotPrintFilter::reset().

### QwtMarker::LineStyle QwtMarker::lineStyle () const

**Returns:**

the line style

**See also:**

For a description of line styles, see **QwtMarker::setLineStyle()**

Definition at line 214 of file qwt\_marker.cpp.

References LineStyle.

Referenced by QwtPlot::closestMarker(), and QwtPlot::markerLineStyle().

### void QwtMarker::markerChanged ()` [protected, virtual]`

Notify a change of parameters.

This virtual function is called when a marker property has been changed and redrawing is advisable. It can be reimplemented by derived classes. The default implementation does nothing.

Reimplemented in **QwtPlotMarker**.

Definition at line 395 of file qwt\_marker.cpp.

Referenced by setFont(), setLabel(), setLabelAlignment(), setLabelColor(), setLabelPen(), setLinePen(), setLineStyle(), setSymbol(), QwtPlotMarker::setXValue(), and QwtPlotMarker::setYValue().

### QwtMarker & QwtMarker::operator= (const QwtMarker & m)

Assignment operator.

**Parameters:**

*m* Marker

Definition at line 51 of file qwt\_marker.cpp.

References QwtText::clone(), d\_align, d\_label, d\_pen, d\_style, and d\_sym.

### void QwtMarker::setFont (const QFont & f)

Specify the font for the label.

**Parameters:**

*f* New font

**See also:**

**QwtMarker::font()**

Definition at line 176 of file qwt\_marker.cpp.

References QwtText::font(), markerChanged(), and QwtText::setFont().

Referenced by QwtPlotPrintFilter::apply(), QwtPlotPrintFilter::reset(), and QwtPlot::setMarkerFont().

### void QwtMarker::setLabel (const QString & text, const QFont & font = `QFont()`, const QColor & color = `QColor()`, const QPen & pen = `QPen(Qt::NoPen)`, const QBrush & brush = `QBrush(Qt::NoBrush)`)

Set the label.

**Parameters:**

*text* Contents of the label text \
 *font* Font of the label text \
 *color* Color of the label text \
 *pen* Pen to draw the enclosing rectangle \
 *brush* Brush to draw the enclosing rectangle

**See also:**

**QwtMarker::label()**

Definition at line 259 of file qwt\_marker.cpp.

References QwtText::alignment(), QwtText::color(), QwtText::font(), label(), QwtText::makeText(), markerChanged(), QwtText::rectBrush(), QwtText::rectPen(), and QwtText::text().

Referenced by QwtPlot::insertLineMarker(), QwtPlot::insertMarker(), setLabelText(), and QwtPlot::setMarkerLabel().

### void QwtMarker::setLabelAlignment (int align)

Set the alignment of the label.

The alignment determines where the label is drawn relative to the marker's position.

**Parameters:**

*align* Alignment. A combination of AlignTop, AlignBottom, AlignLeft, AlignRight, AlignCenter, AlgnHCenter, AlignVCenter.

**See also:**

**QwtMarker::labelAlignment()**

Definition at line 298 of file qwt\_marker.cpp.

References markerChanged().

Referenced by QwtPlot::insertLineMarker(), and QwtPlot::setMarkerLabelAlign().

### void QwtMarker::setLabelColor (const QColor & color)

Specify a color for the label.

**Parameters:**

*color* Color of the label text

**See also:**

**QwtMarker::labelColor()**

Definition at line 344 of file qwt\_marker.cpp.

References QwtText::color(), markerChanged(), and QwtText::setColor().

### void QwtMarker::setLabelPen (const QPen & p)

Specify a pen for the label.

**Parameters:**

*p* New pen

**See also:**

**QwtMarker::labelPen()**

**Warning:**

This function is deprecated. Use **QwtMarker::setLabelColor**.

Definition at line 368 of file qwt\_marker.cpp.

References QwtText::color(), markerChanged(), and QwtText::setColor().

Referenced by QwtPlotPrintFilter::apply(), QwtPlotPrintFilter::reset(), QwtPlot::setMarkerLabelPen(), and QwtPlot::setMarkerPen().

### void QwtMarker::setLabelText (const QString & text)

Set the label text.

**Parameters:**

*text* label text

**See also:**

**QwtMarker::label()**

Definition at line 244 of file qwt\_marker.cpp.

References QwtText::color(), QwtText::font(), QwtText::rectBrush(), QwtText::rectPen(), and setLabel().

Referenced by QwtPlot::setMarkerLabelText().

### void QwtMarker::setLinePen (const QPen & p)

Specify a pen for the line.

**Parameters:**

*p* New pen

**See also:**

**QwtMarker::linePen()**

Definition at line 321 of file qwt\_marker.cpp.

References markerChanged().

Referenced by QwtPlotPrintFilter::apply(), QwtPlotPrintFilter::reset(), QwtPlot::setMarkerLinePen(), and QwtPlot::setMarkerPen().

### void QwtMarker::setLineStyle (QwtMarker::LineStyle st)

Set the line style.

**Parameters:**

*st* Line style. Can be one of QwtMarker::NoLine, QwtMarker::HLine, QwtMarker::VLine or QwtMarker::Cross

**See also:**

**QwtMarker::lineStyle()**

Definition at line 201 of file qwt\_marker.cpp.

References markerChanged().

Referenced by QwtPlot::insertLineMarker(), and QwtPlot::setMarkerLineStyle().

### void QwtMarker::setSymbol (const QwtSymbol & s)

Assign a symbol.

**Parameters:**

*s* New symbol

**See also:**

**QwtSymbol**, **QwtMarker::symbol()**

Definition at line 224 of file qwt\_marker.cpp.

References markerChanged().

Referenced by QwtPlotPrintFilter::apply(), QwtPlotPrintFilter::reset(), and QwtPlot::setMarkerSymbol().

### const QwtSymbol & QwtMarker::symbol () const

**Returns:**

the symbol

**See also:**

**QwtMarker::setSymbol()**, **QwtSymbol**

Definition at line 234 of file qwt\_marker.cpp.

Referenced by QwtPlotPrintFilter::apply(), QwtPlot::closestMarker(), QwtPlot::markerSymbol(), and QwtPlotPrintFilter::reset().

## Author

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