QwtRoundScaleDraw.qt5 - Man Page


#include <qwt_round_scale_draw.h>

Inherits QwtAbstractScaleDraw.

Inherited by QwtDialScaleDraw.

Public Member Functions

QwtRoundScaleDraw ()
QwtRoundScaleDraw (const QwtRoundScaleDraw &)
virtual ~QwtRoundScaleDraw ()
QPoint center () const
virtual int extent (const QPen &, const QFont &) const
void moveCenter (int x, int y)
void moveCenter (const QPoint &)
QwtRoundScaleDraw & operator= (const QwtRoundScaleDraw &other)
int radius () const
void setAngleRange (double angle1, double angle2)
void setRadius (int radius)

Protected Member Functions

virtual void drawBackbone (QPainter *p) const
virtual void drawLabel (QPainter *p, double val) const
virtual void drawTick (QPainter *p, double val, int len) const

Additional Inherited Members

Detailed Description

A class for drawing round scales.

QwtRoundScaleDraw can be used to draw round scales. The circle segment can be adjusted by QwtRoundScaleDraw::setAngleRange(). The geometry of the scale can be specified with QwtRoundScaleDraw::moveCenter() and QwtRoundScaleDraw::setRadius().

After a scale division has been specified as a QwtScaleDiv object using QwtAbstractScaleDraw::setScaleDiv(const QwtScaleDiv &s), the scale can be drawn with the QwtAbstractScaleDraw::draw() member.

Constructor & Destructor Documentation

QwtRoundScaleDraw::QwtRoundScaleDraw ()

Constructor. The range of the scale is initialized to [0, 100], The center is set to (50, 50) with a radius of 50. The angle range is set to [-135, 135].

Member Function Documentation

void QwtRoundScaleDraw::drawBackbone (QPainter *painter) const [protected], [virtual]

Draws the baseline of the scale


painter Painter

See also:

drawTick(), drawLabel()

Implements QwtAbstractScaleDraw.

void QwtRoundScaleDraw::drawLabel (QPainter *painter, doublevalue) const [protected], [virtual]

Draws the label for a major scale tick


painter Painter
value Value

See also:

drawTick(), drawBackbone()

Implements QwtAbstractScaleDraw.

void QwtRoundScaleDraw::drawTick (QPainter *painter, doublevalue, intlen) const [protected], [virtual]

Draw a tick


painter Painter
value Value of the tick
len Lenght of the tick

See also:

drawBackbone(), drawLabel()

Implements QwtAbstractScaleDraw.

int QwtRoundScaleDraw::extent (const QPen &pen, const QFont &font) const [virtual]

Calculate the extent of the scale

The extent is the distcance between the baseline to the outermost pixel of the scale draw. radius() + extent() is an upper limit for the radius of the bounding circle.


pen Pen that is used for painting backbone and ticks
font Font used for painting the labels

See also:

setMinimumExtent(), minimumExtent()


The implemented algo is not too smart and calculates only an upper limit, that might be a few pixels too large

Implements QwtAbstractScaleDraw.

void QwtRoundScaleDraw::moveCenter (const QPoint &center)

Move the center of the scale draw, leaving the radius unchanged


center New center

See also:


int QwtRoundScaleDraw::radius () const

Get the radius

Radius is the radius of the backbone without ticks and labels.

See also:

setRadius(), extent()

void QwtRoundScaleDraw::setAngleRange (doubleangle1, doubleangle2)

Adjust the baseline circle segment for round scales. The baseline will be drawn from min(angle1,angle2) to max(angle1, angle2). The default setting is [ -135, 135 ]. An angle of 0 degrees corresponds to the 12 o'clock position, and positive angles count in a clockwise direction.


angle2 boundaries of the angle interval in degrees.

  • The angle range is limited to [-360, 360] degrees. Angles exceeding this range will be clipped.
  • For angles more than 359 degrees above or below min(angle1, angle2), scale marks will not be drawn.
  • If you need a counterclockwise scale, use QwtScaleDiv::setRange

void QwtRoundScaleDraw::setRadius (intradius)

Change of radius the scale

Radius is the radius of the backbone without ticks and labels.


radius New Radius

See also:



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Tue Nov 20 2012 Version 5.2.3 Qwt User's Guide