QwtRoundScaleDraw - Man Page

A class for drawing round scales.

Synopsis

#include <qwt_round_scale_draw.h>

Inherits QwtAbstractScaleDraw.

Inherited by QwtAnalogClockScaleDraw, and QwtCompassScaleDraw.

Public Member Functions

QwtRoundScaleDraw ()
Constructor.
virtual ~QwtRoundScaleDraw ()
Destructor.
void setRadius (double radius)
double radius () const
void moveCenter (double x, double y)
Move the center of the scale draw, leaving the radius unchanged.
void moveCenter (const QPointF &)
QPointF center () const
Get the center of the scale.
void setAngleRange (double angle1, double angle2)
Adjust the baseline circle segment for round scales.
virtual double extent (const QFont &) const

Protected Member Functions

virtual void drawTick (QPainter *, double value, double len) const
virtual void drawBackbone (QPainter *) const
virtual void drawLabel (QPainter *, double val) 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 setAngleRange(). The geometry of the scale can be specified with moveCenter() and 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

Parameters

painter Painter

See also

drawTick(), drawLabel()

Implements QwtAbstractScaleDraw.

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

Draws the label for a major scale tick

Parameters

painter Painter
value Value

See also

drawTick(), drawBackbone()

Implements QwtAbstractScaleDraw.

void QwtRoundScaleDraw::drawTick (QPainter * painter, double value, double len) const [protected], [virtual]

Draw a tick

Parameters

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

See also

drawBackbone(), drawLabel()

Implements QwtAbstractScaleDraw.

double QwtRoundScaleDraw::extent (const QFont & font) const [virtual]

Calculate the extent of the scale

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

Parameters

font Font used for painting the labels

Returns

Calculated extent

See also

setMinimumExtent(), minimumExtent()

Warning

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

Implements QwtAbstractScaleDraw.

void QwtRoundScaleDraw::moveCenter (const QPointF & center)

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

Parameters

center New center

See also

setRadius()

double QwtRoundScaleDraw::radius () const

Get the radius

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

Returns

Radius of the scale

See also

setRadius(), extent()

void QwtRoundScaleDraw::setAngleRange (double angle1, double angle2)

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.

Parameters

angle1
angle2 boundaries of the angle interval in degrees.

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

void QwtRoundScaleDraw::setRadius (double radius)

Change of radius the scale

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

Parameters

radius New Radius

See also

moveCenter()

Author

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Info

Mon Jun 1 2020 Version 6.1.5 Qwt User's Guide