A abstract base class for drawing scales. More...

#include <qwt_abstract_scale_draw.h>

Inheritance diagram for QwtAbstractScaleDraw:

Public Types
enum	ScaleComponent { Backbone = 0x01, Ticks = 0x02, Labels = 0x04 }
typedef QFlags< ScaleComponent >	ScaleComponents
Public Member Functions
virtual void	draw (QPainter *, const QPalette &) const
void	enableComponent (ScaleComponent, bool enable=true)
virtual double	extent (const QFont &) const =0
bool	hasComponent (ScaleComponent) const
virtual QwtText	label (double) const
double	maxTickLength () const
double	minimumExtent () const
int	penWidth () const
	QwtAbstractScaleDraw ()
const QwtScaleDiv &	scaleDiv () const
const QwtScaleMap &	scaleMap () const
QwtScaleMap &	scaleMap ()
void	setMinimumExtent (double)
void	setPenWidth (int width)
void	setScaleDiv (const QwtScaleDiv &s)
void	setSpacing (double margin)
void	setTickLength (QwtScaleDiv::TickType, double length)
void	setTransformation (QwtScaleTransformation *)
double	spacing () const
double	tickLength (QwtScaleDiv::TickType) const
virtual	~QwtAbstractScaleDraw ()
Protected Member Functions
virtual void	drawBackbone (QPainter *painter) const =0
virtual void	drawLabel (QPainter *painter, double value) const =0
virtual void	drawTick (QPainter *painter, double value, double len) const =0
void	invalidateCache ()
const QwtText &	tickLabel (const QFont &, double value) const

Detailed Description

A abstract base class for drawing scales.

QwtAbstractScaleDraw can be used to draw linear or logarithmic scales.

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 Typedef Documentation

typedef QFlags<ScaleComponent> QwtAbstractScaleDraw::ScaleComponents

Scale components.

Member Enumeration Documentation

enum QwtAbstractScaleDraw::ScaleComponent

Components of a scale

See also:: enableComponent(), hasComponent

Enumerator:

Backbone	Backbone = the line where the ticks are located.
Ticks	Ticks.
Labels	Labels.

Constructor & Destructor Documentation

QwtAbstractScaleDraw::QwtAbstractScaleDraw ( )

Constructor.

The range of the scale is initialized to [0, 100], The spacing (distance between ticks and labels) is set to 4, the tick lengths are set to 4,6 and 8 pixels

QwtAbstractScaleDraw::~QwtAbstractScaleDraw ( ) [virtual]

Destructor.

Member Function Documentation

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

Draw the scale.

Parameters:

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

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

Draws the baseline of the scale

Parameters:

painter Painter

See also:: drawTick(), drawLabel()

Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

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

Draws the label for a major scale tick

Parameters:

painter	Painter
value	Value

See also:: drawTick(), drawBackbone()

Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

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

Draw a tick

Parameters:

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

See also:: drawBackbone(), drawLabel()

Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

void QwtAbstractScaleDraw::enableComponent	(	ScaleComponent	component,
		bool	enable = `true`
	)

En/Disable a component of the scale

Parameters:

component	Scale component
enable	On/Off

See also:: hasComponent()

virtual double QwtAbstractScaleDraw::extent ( const QFont & ) const [pure virtual]

Calculate the extent

The extent is the distcance from the baseline to the outermost pixel of the scale draw in opposite to its orientation. It is at least minimumExtent() pixels.

See also:: setMinimumExtent(), minimumExtent()

Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

bool QwtAbstractScaleDraw::hasComponent ( ScaleComponent component ) const

Check if a component is enabled

See also:: enableComponent()

void QwtAbstractScaleDraw::invalidateCache ( ) [protected]

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, invalidateCache() needs to be called manually.

QwtText QwtAbstractScaleDraw::label ( double value ) const [virtual]

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:

value Value

Returns:: Label string.

Reimplemented in QwtDialScaleDraw.

double QwtAbstractScaleDraw::maxTickLength ( ) const

Returns:: Length of the longest tick

Useful for layout calculations

See also:: tickLength(), setTickLength()

double QwtAbstractScaleDraw::minimumExtent ( ) const

Get the minimum extent

See also:: extent(), setMinimumExtent()

int QwtAbstractScaleDraw::penWidth ( ) const

Returns:: Scale pen width

See also:: setPenWidth()

Reimplemented in QwtDialScaleDraw.

const QwtScaleDiv & QwtAbstractScaleDraw::scaleDiv ( ) const

Returns:: scale division

const QwtScaleMap & QwtAbstractScaleDraw::scaleMap ( ) const

Returns:: Map how to translate between scale and pixel values

QwtScaleMap & QwtAbstractScaleDraw::scaleMap ( )

Returns:: Map how to translate between scale and pixel values

void QwtAbstractScaleDraw::setMinimumExtent ( double minExtent )

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:

minExtent Minimum extent

See also:: extent(), minimumExtent()

void QwtAbstractScaleDraw::setPenWidth ( int width )

Specify the width of the scale pen.

Parameters:

width Pen width

See also:: penWidth()

void QwtAbstractScaleDraw::setScaleDiv ( const QwtScaleDiv & sd )

Change the scale division

Parameters:

sd	New scale division

void QwtAbstractScaleDraw::setSpacing ( double spacing )

Set the spacing between tick and labels.

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

Parameters:

spacing Spacing

See also:: spacing()

void QwtAbstractScaleDraw::setTickLength	(	QwtScaleDiv::TickType	tickType,
		double	length
	)

Set the length of the ticks

Parameters:

tickType	Tick type
length	New length

Warning:: the length is limited to [0..1000]

void QwtAbstractScaleDraw::setTransformation ( QwtScaleTransformation * transformation )

Change the transformation of the scale

Parameters:

transformation New scale transformation

double QwtAbstractScaleDraw::spacing ( ) const

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]`

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:

font	Font
value	Value

Returns:: Tick label

double QwtAbstractScaleDraw::tickLength ( QwtScaleDiv::TickType tickType ) const

Return the length of the ticks

See also:: setTickLength(), maxTickLength()

QwtAbstractScaleDraw Class Reference

Public Types

Public Member Functions

Protected Member Functions

Detailed Description

Member Typedef Documentation

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation