Qwt User's Guide 5.2.2
Public Types | Public Member Functions | Protected Member Functions

QwtRoundScaleDraw Class Reference

A class for drawing round scales. More...

#include <qwt_round_scale_draw.h>

Inheritance diagram for QwtRoundScaleDraw:
Inheritance graph
[legend]

List of all members.

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) const
int majTickLength () const
const QwtScaleMapmap () const
int minimumExtent () const
void moveCenter (const QPoint &)
void moveCenter (int x, int y)
QwtRoundScaleDrawoperator= (const QwtRoundScaleDraw &other)
 QwtRoundScaleDraw (const QwtRoundScaleDraw &)
 QwtRoundScaleDraw ()
int radius () const
const QwtScaleDivscaleDiv () const
QwtScaleMapscaleMap ()
void setAngleRange (double angle1, double angle2)
void setMinimumExtent (int)
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
virtual ~QwtRoundScaleDraw ()

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 QwtTexttickLabel (const QFont &, double value) const

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.


Member Enumeration Documentation

Components of a scale

  • Backbone
  • Ticks
  • Labels
See also:
enableComponent(), hasComponent

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].

QwtRoundScaleDraw::QwtRoundScaleDraw ( const QwtRoundScaleDraw other)

Copy constructor.

QwtRoundScaleDraw::~QwtRoundScaleDraw ( ) [virtual]

Destructor.


Member Function Documentation

QPoint QwtRoundScaleDraw::center ( ) const

Get the center of the scale.

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

Draw the scale.

Parameters:
painterThe painter
palettePalette, text color is used for the labels, foreground color for ticks and backbone
void QwtRoundScaleDraw::drawBackbone ( QPainter *  painter) const [protected, virtual]

Draws the baseline of the scale

Parameters:
painterPainter
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:
painterPainter
valueValue
See also:
drawTick(), drawBackbone()

Implements QwtAbstractScaleDraw.

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

Draw a tick

Parameters:
painterPainter
valueValue of the tick
lenLenght of the tick
See also:
drawBackbone(), drawLabel()

Implements QwtAbstractScaleDraw.

void QwtAbstractScaleDraw::enableComponent ( ScaleComponent  component,
bool  enable = true 
) [inherited]

En/Disable a component of the scale

Parameters:
componentScale component
enableOn/Off
See also:
hasComponent()
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.

Parameters:
penPen that is used for painting backbone and ticks
fontFont used for painting the labels
See also:
setMinimumExtent(), minimumExtent()
Warning:
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 ( ScaleComponent  component) const [inherited]

Check if a component is enabled

See also:
enableComponent()
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 QwtAbstractScaleDraw::label ( double  value) const [virtual, inherited]

Convert a value into its representing label.

The value is converted to a plain text using QLocale::system().toString(value). This method is often overloaded by applications to have individual labels.

Parameters:
valueValue
Returns:
Label string.

Reimplemented in QwtDialScaleDraw.

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 ( const QPoint &  center)

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

Parameters:
centerNew center
See also:
setRadius()
void QwtRoundScaleDraw::moveCenter ( int  x,
int  y 
) [inline]

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

QwtRoundScaleDraw & QwtRoundScaleDraw::operator= ( const QwtRoundScaleDraw other)

Assignment operator.

int QwtRoundScaleDraw::radius ( ) const

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 ( 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
angle2boundaries 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 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 ( int  minExtent) [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.

Parameters:
minExtentMinimum extent
See also:
extent(), minimumExtent()
void QwtRoundScaleDraw::setRadius ( int  radius)

Change of radius the scale

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

Parameters:
radiusNew Radius
See also:
moveCenter()
void QwtAbstractScaleDraw::setScaleDiv ( const QwtScaleDiv sd) [inherited]

Change the scale division

Parameters:
sdNew scale division
void QwtAbstractScaleDraw::setSpacing ( int  spacing) [inherited]

Set the spacing between tick and labels.

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

Parameters:
spacingSpacing
See also:
spacing()
void QwtAbstractScaleDraw::setTickLength ( QwtScaleDiv::TickType  tickType,
int  length 
) [inherited]

Set the length of the ticks

Parameters:
tickTypeTick type
lengthNew length
Warning:
the length is limited to [0..1000]
void QwtAbstractScaleDraw::setTransformation ( QwtScaleTransformation transformation) [inherited]

Change the transformation of the scale

Parameters:
transformationNew 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:
setSpacing()
const QwtText & QwtAbstractScaleDraw::tickLabel ( const QFont &  font,
double  value 
) 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.

Parameters:
fontFont
valueValue
Returns:
Tick label
int QwtAbstractScaleDraw::tickLength ( QwtScaleDiv::TickType  tickType) const [inherited]

Return the length of the ticks

See also:
setTickLength(), majTickLength()