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

#include <qwt_abstract_scale_draw.h>

Inheritance diagram for QwtAbstractScaleDraw:

Classes
class	PrivateData

Public Types
enum	ScaleComponent { Backbone = 0x01 , Ticks = 0x02 , Labels = 0x04 }
	Components of a scale. More...

Public Member Functions
	QwtAbstractScaleDraw ()
	Constructor for QwtAbstractScaleDraw.

void	setScaleDiv (const QwtScaleDiv &)
	Set the scale division.

const QwtScaleDiv &	scaleDiv () const
	Return the scale division.

void	setTransformation (QwtTransform *)
	Set the scale transformation.

const QwtScaleMap &	scaleMap () const
	Return the scale map (const version)

QwtScaleMap &	scaleMap ()
	Return the scale map (non-const version)

void	enableComponent (ScaleComponent, bool enable=true)
	Enable or disable a scale component.

bool	hasComponent (ScaleComponent) const
	Check if a component is enabled.

void	setTickLength (QwtScaleDiv::TickType, double length)
	Set the length of the ticks.

double	tickLength (QwtScaleDiv::TickType) const
	Get the length of the ticks.

double	maxTickLength () const
	Get the length of the longest tick.

void	setSpacing (double)
	Set the spacing between tick and labels.

double	spacing () const
	Get the spacing.

void	setPenWidthF (qreal width)
	Specify the width of the scale pen.

qreal	penWidthF () const
	Get the scale pen width.

void	setSelected (bool on)
	Set whether the scale draw is selected.

bool	isSelected () const
	Check if the scale draw is selected.

void	setSelectedPenWidthOffset (qreal offset=1)
	Set the pen width offset for the axis when it is in selected state.

qreal	selectedPenWidthOffset () const
	Get the current pen width offset for the axis when it is in selected state.

virtual void	draw (QPainter *, const QPalette &) const
	Draw the scale.

virtual QwtText	label (double) const
	Convert a value into its representing label.

virtual double	extent (const QFont &font) const =0

void	setMinimumExtent (double)
	Set a minimum for the extent.

double	minimumExtent () const
	Get the minimum extent.

void	invalidateCache ()
	Invalidate the cache used by tickLabel()

Protected Member Functions
virtual void	drawTick (QPainter *painter, double value, double len) const =0

virtual void	drawBackbone (QPainter *painter) const =0

virtual void	drawLabel (QPainter *painter, double value) const =0

const QwtText &	tickLabel (const QFont &, double value) const
	Convert a value into its representing label and cache it.

Detailed Description

An 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 setScaleDiv(), the scale can be drawn with the draw() member.

Member Enumeration Documentation

◆ ScaleComponent

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::QwtAbstractScaleDraw ( )

Constructor for QwtAbstractScaleDraw.

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.

Destructor for QwtAbstractScaleDraw

Member Function Documentation

◆ draw()

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

◆ drawBackbone()

virtual void QwtAbstractScaleDraw::drawBackbone ( QPainter * painter ) const

protectedpure virtual

Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

◆ drawLabel()

virtual void QwtAbstractScaleDraw::drawLabel	(	QPainter *	painter,
		double	value
	)		const

protectedpure virtual

Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

◆ drawTick()

virtual void QwtAbstractScaleDraw::drawTick	(	QPainter *	painter,
		double	value,
		double	len
	)		const

protectedpure virtual

Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

◆ enableComponent()

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

Enable or disable a scale component.

Parameters

component	Scale component (Backbone, Ticks, or Labels)
enable	True to enable, false to disable

See also: hasComponent()

◆ extent()

virtual double QwtAbstractScaleDraw::extent ( const QFont & font ) const

pure virtual

Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

◆ hasComponent()

bool QwtAbstractScaleDraw::hasComponent ( ScaleComponent component ) const

Check if a component is enabled.

Parameters

component Component type

Returns: True if component is enabled

See also: enableComponent()

◆ invalidateCache()

void QwtAbstractScaleDraw::invalidateCache ( )

Invalidate the cache used by 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.

◆ isSelected()

bool QwtAbstractScaleDraw::isSelected ( ) const

Check if the scale draw is selected.

Returns: True if selected, false otherwise

◆ label()

QwtText QwtAbstractScaleDraw::label ( double value ) const

virtual

Convert a value into its representing label.

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

Parameters

value Value

Returns: Label string

Reimplemented in QwtCompassScaleDraw, and QwtDateScaleDraw.

◆ maxTickLength()

double QwtAbstractScaleDraw::maxTickLength ( ) const

Get the length of the longest tick.

Returns: Length of the longest tick

Useful for layout calculations

See also: tickLength(), setTickLength()

◆ minimumExtent()

double QwtAbstractScaleDraw::minimumExtent ( ) const

Get the minimum extent.

Returns: Minimum extent

See also: extent(), setMinimumExtent()

◆ penWidthF()

qreal QwtAbstractScaleDraw::penWidthF ( ) const

Get the scale pen width.

Returns: Scale pen width

See also: setPenWidth()

◆ scaleDiv()

const QwtScaleDiv & QwtAbstractScaleDraw::scaleDiv ( ) const

Return the scale division.

Returns: Current scale division object

◆ scaleMap() [1/2]

QwtScaleMap & QwtAbstractScaleDraw::scaleMap ( )

Return the scale map (non-const version)

Returns: Map for translating between scale and pixel values

◆ scaleMap() [2/2]

const QwtScaleMap & QwtAbstractScaleDraw::scaleMap ( ) const

Return the scale map (const version)

Returns: Map for translating between scale and pixel values

◆ selectedPenWidthOffset()

qreal QwtAbstractScaleDraw::selectedPenWidthOffset ( ) const

Get the current pen width offset for the axis when it is in selected state.

Returns: The current width offset value

See also: setSelectedPenWidthOffset()

◆ setMinimumExtent()

void QwtAbstractScaleDraw::setMinimumExtent ( double minExtent )

Set a minimum for the extent.

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

Parameters

minExtent Minimum extent

See also: extent(), minimumExtent()

◆ setPenWidthF()

void QwtAbstractScaleDraw::setPenWidthF ( qreal width )

Specify the width of the scale pen.

Parameters

width Pen width

See also: penWidth()

◆ setScaleDiv()

void QwtAbstractScaleDraw::setScaleDiv ( const QwtScaleDiv & scaleDiv )

Set the scale division.

Parameters

scaleDiv New scale division object

This also updates the scale map and clears the label cache.

◆ setSelected()

void QwtAbstractScaleDraw::setSelected ( bool on )

Set whether the scale draw is selected.

Parameters

on	True to select, false to deselect

◆ setSelectedPenWidthOffset()

void QwtAbstractScaleDraw::setSelectedPenWidthOffset ( qreal offset = 1 )

Set the pen width offset for the axis when it is in selected state.

When an axis (e.g., X-axis or Y-axis) is selected by the user, the pen width used for drawing will be increased by this offset value, achieving a visual highlighting effect.

Parameters

offset The additional width value to be added when selected (unit: pixels). This value should be non-negative. If it is 0, the line width in selected state will be the same as in normal state.

See also: selectedPenWidthOffset()

◆ setSpacing()

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()

◆ setTickLength()

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]

◆ setTransformation()

void QwtAbstractScaleDraw::setTransformation ( QwtTransform * transformation )

Set the scale transformation.

Parameters

transformation New scale transformation object

◆ spacing()

double QwtAbstractScaleDraw::spacing ( ) const

Get the spacing.

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

Returns: Spacing

See also: setSpacing()

◆ tickLabel()

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

◆ tickLength()

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

Get the length of the ticks.

Returns: Length of the ticks

See also: setTickLength(), maxTickLength()

The documentation for this class was generated from the following files:

/home/runner/work/QWT/QWT/src/plot/qwt_abstract_scale_draw.h
/home/runner/work/QWT/QWT/src/plot/qwt_abstract_scale_draw.cpp

Classes

Public Types

Public Member Functions

Protected Member Functions

Detailed Description

Member Enumeration Documentation

◆ ScaleComponent

Constructor & Destructor Documentation

◆ QwtAbstractScaleDraw()

Member Function Documentation

◆ draw()

◆ drawBackbone()

◆ drawLabel()

◆ drawTick()

◆ enableComponent()

◆ extent()

◆ hasComponent()

◆ invalidateCache()

◆ isSelected()

◆ label()

◆ maxTickLength()

◆ minimumExtent()

◆ penWidthF()

◆ scaleDiv()

◆ scaleMap() [1/2]

◆ scaleMap() [2/2]

◆ selectedPenWidthOffset()

◆ setMinimumExtent()

◆ setPenWidthF()

◆ setScaleDiv()

◆ setSelected()

◆ setSelectedPenWidthOffset()

◆ setSpacing()

◆ setTickLength()

◆ setTransformation()

◆ spacing()

◆ tickLabel()

◆ tickLength()