QwtDialScaleDraw man page

QwtDialScaleDraw —

A special scale draw made for QwtDial.


#include <qwt_dial.h>

Inherits QwtRoundScaleDraw.

Public Types

enum ScaleComponent { Backbone = 1, Ticks = 2, Labels = 4 }

Public Member Functions

QPoint center () const

virtual void draw (QPainter *, const QPalette &) const

void enableComponent (ScaleComponent, bool enable=true)

virtual int extent (const QPen &, const QFont &) const

bool hasComponent (ScaleComponent) const

virtual QwtText label (double value) const

int majTickLength () const

const QwtScaleMap & map () const

int minimumExtent () const

void moveCenter (const QPoint &)

void moveCenter (int x, int y)

uint penWidth () const

QwtDialScaleDraw (QwtDial *)

int radius () const

const QwtScaleDiv & scaleDiv () const

QwtScaleMap & scaleMap ()

void setAngleRange (double angle1, double angle2)

void setMinimumExtent (int)

void setPenWidth (uint)

void setRadius (int radius)

void setScaleDiv (const QwtScaleDiv &s)

void setSpacing (int margin)

void setTickLength (QwtScaleDiv::TickType, int length)

void setTransformation (QwtScaleTransformation *)

int spacing () const

int tickLength (QwtScaleDiv::TickType) const

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

void invalidateCache ()

const QwtText & tickLabel (const QFont &, double value) const

Detailed Description

A special scale draw made for QwtDial.

See also:

QwtDial, QwtCompass

Member Enumeration Documentation

enum QwtAbstractScaleDraw::ScaleComponent [inherited] Components of a scale


See also:

enableComponent(), hasComponent

Constructor & Destructor Documentation

QwtDialScaleDraw::QwtDialScaleDraw (QwtDial *parent) [explicit] Constructor


parent Parent dial widget

Member Function Documentation

QPoint QwtRoundScaleDraw::center () const [inherited]

Get the center of the scale.

void QwtAbstractScaleDraw::draw (QPainter *painter, const QPalette &palette) const [virtual, inherited]

Draw the scale. Parameters:

painter The painter
palette Palette, text color is used for the labels, foreground color for ticks and backbone

void QwtRoundScaleDraw::drawBackbone (QPainter *painter) const [protected, virtual, inherited] Draws the baseline of the scale


painter Painter

See also:

drawTick(), drawLabel()

Implements QwtAbstractScaleDraw.

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


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

See also:

drawBackbone(), drawLabel()

Implements QwtAbstractScaleDraw.

void QwtAbstractScaleDraw::enableComponent (ScaleComponentcomponent, boolenable = true) [inherited] En/Disable a component of the scale


component Scale component
enable On/Off

See also:


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

bool QwtAbstractScaleDraw::hasComponent (ScaleComponentcomponent) const [inherited] Check if a component is enabled

See also:


void QwtAbstractScaleDraw::invalidateCache () [protected, inherited] Invalidate the cache used by QwtAbstractScaleDraw::tickLabel

The cache is invalidated, when a new QwtScaleDiv is set. If the labels need to be changed. while the same QwtScaleDiv is set, QwtAbstractScaleDraw::invalidateCache needs to be called manually.

QwtText QwtDialScaleDraw::label (doublevalue) const [virtual] Call QwtDial::scaleLabel of the parent dial widget.


value Value to display

See also:


Reimplemented from QwtAbstractScaleDraw.

int QwtAbstractScaleDraw::majTickLength () const [inherited] The same as QwtAbstractScaleDraw::tickLength(QwtScaleDiv::MajorTick).

const QwtScaleMap & QwtAbstractScaleDraw::map () const [inherited] Returns

Map how to translate between scale and pixel values

int QwtAbstractScaleDraw::minimumExtent () const [inherited] Get the minimum extent

See also:

extent(), setMinimumExtent()

void QwtRoundScaleDraw::moveCenter (intx, inty) [inline, inherited]

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

void QwtRoundScaleDraw::moveCenter (const QPoint &center) [inherited] Move the center of the scale draw, leaving the radius unchanged


center New center

See also:


uint QwtDialScaleDraw::penWidth () const Returns

Pen width used for painting the scale

See also:

setPenWidth, QwtDial::drawScale()

int QwtRoundScaleDraw::radius () const [inherited] Get the radius

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

See also:

setRadius(), extent()

const QwtScaleDiv & QwtAbstractScaleDraw::scaleDiv () const [inherited] Returns

scale division

QwtScaleMap & QwtAbstractScaleDraw::scaleMap () [inherited] Returns

Map how to translate between scale and pixel values

void QwtRoundScaleDraw::setAngleRange (doubleangle1, doubleangle2) [inherited]

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 QwtAbstractScaleDraw::setMinimumExtent (intminExtent) [inherited]

Set a minimum for the extent. The extent is calculated from the coomponents of the scale draw. In situations, where the labels are changing and the layout depends on the extent (f.e scrolling a scale), setting an upper limit as minimum extent will avoid jumps of the layout.


minExtent Minimum extent

See also:

extent(), minimumExtent()

void QwtDialScaleDraw::setPenWidth (uintpenWidth) Set the pen width used for painting the scale


penWidth Pen width

See also:

penWidth(), QwtDial::drawScale()

void QwtRoundScaleDraw::setRadius (intradius) [inherited] Change of radius the scale

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


radius New Radius

See also:


void QwtAbstractScaleDraw::setScaleDiv (const QwtScaleDiv &sd) [inherited] Change the scale division


sd New scale division

void QwtAbstractScaleDraw::setSpacing (intspacing) [inherited]

Set the spacing between tick and labels. The spacing is the distance between ticks and labels. The default spacing is 4 pixels.


spacing Spacing

See also:


void QwtAbstractScaleDraw::setTickLength (QwtScaleDiv::TickTypetickType, intlength) [inherited] Set the length of the ticks


tickType Tick type
length New length


the length is limited to [0..1000]

void QwtAbstractScaleDraw::setTransformation (QwtScaleTransformation *transformation) [inherited] Change the transformation of the scale


transformation New scale transformation

int QwtAbstractScaleDraw::spacing () const [inherited]

Get the spacing. The spacing is the distance between ticks and labels. The default spacing is 4 pixels.

See also:


const QwtText & QwtAbstractScaleDraw::tickLabel (const QFont &font, doublevalue) const [protected, inherited]

Convert a value into its representing label and cache it. The conversion between value and label is called very often in the layout and painting code. Unfortunately the calculation of the label sizes might be slow (really slow for rich text in Qt4), so it's necessary to cache the labels.


font Font
value Value


Tick label

int QwtAbstractScaleDraw::tickLength (QwtScaleDiv::TickTypetickType) const [inherited] Return the length of the ticks

See also:

setTickLength(), majTickLength()


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Qwt User's Guide Version 5.2.2 Mon Aug 1 2011