---
name: "QwtCompass"
section: "3"
platform: "linux"
package: "libqwt-doc"
version: "6.1.4-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/QwtCompass"
---

# QwtCompass(3)

A Compass Widget.

## NAME

QwtCompass - A Compass Widget.

## SYNOPSIS

`#include <qwt_compass.h>`

Inherits **QwtDial**.

### Public Member Functions

**QwtCompass** (QWidget \*parent=NULL)\
 Constructor.  virtual **~QwtCompass** ()\
 Destructor.  void **setRose** (**QwtCompassRose** \***rose**)\
 const **QwtCompassRose** \* **rose** () const\
 **QwtCompassRose** \* **rose** ()\

### Protected Member Functions

virtual void **drawRose** (QPainter \*, const QPointF &center, double radius, double north, QPalette::ColorGroup) const\
 virtual void **drawScaleContents** (QPainter \*, const QPointF &center, double radius) const\
 virtual void **keyPressEvent** (QKeyEvent \*)\

### Additional Inherited Members

## Detailed Description

A Compass Widget.

**QwtCompass** is a widget to display and enter directions. It consists of a scale, an optional needle and rose.

**Note:**

The examples/dials example shows how to use **QwtCompass**.

## Constructor & Destructor Documentation

### QwtCompass::QwtCompass (QWidget \* parent = `NULL`)` [explicit]`

Constructor.

**Parameters:**

*parent* Parent widget

Create a compass widget with a scale, no needle and no rose. The default origin is 270.0 with no valid value. It accepts mouse and keyboard inputs and has no step size. The default mode is **QwtDial::RotateNeedle**.

## Member Function Documentation

### void QwtCompass::drawRose (QPainter \* painter, const QPointF & center, double radius, double north, QPalette::ColorGroup cg) const` [protected]`, ` [virtual]`

Draw the compass rose

**Parameters:**

*painter* Painter \
 *center* Center of the compass \
 *radius* of the circle, where to paint the rose \
 *north* Direction pointing north, in degrees counter clockwise \
 *cg* Color group

### void QwtCompass::drawScaleContents (QPainter \* painter, const QPointF & center, double radius) const` [protected]`, ` [virtual]`

Draw the contents of the scale

**Parameters:**

*painter* Painter \
 *center* Center of the content circle \
 *radius* Radius of the content circle

Reimplemented from **QwtDial**.

### void QwtCompass::keyPressEvent (QKeyEvent \* kev)` [protected]`, ` [virtual]`

Handles key events

Beside the keys described in **QwtDial::keyPressEvent** numbers from 1-9 (without 5) set the direction according to their position on the num pad.

**See also:**

**isReadOnly()**

Reimplemented from **QwtAbstractSlider**.

### const QwtCompassRose \* QwtCompass::rose () const

**Returns:**

rose

**See also:**

**setRose()**

### QwtCompassRose \* QwtCompass::rose ()

**Returns:**

rose

**See also:**

**setRose()**

### void QwtCompass::setRose (QwtCompassRose \* rose)

Set a rose for the compass

**Parameters:**

*rose* Compass rose

**Warning:**

The rose will be deleted, when a different rose is set or in ~QwtCompass

**See also:**

**rose()**

## Author

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