A 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.

virtual	~QwtAbstractScaleDraw ()
	Destructor.

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

const QwtScaleDiv &	scaleDiv () const

void	setTransformation (QwtTransform *)
	Change the transformation of the scale.

const QwtScaleMap &	scaleMap () const

QwtScaleMap &	scaleMap ()

void	enableComponent (ScaleComponent, bool enable=true)
	En/Disable a component of the scale.

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

double	maxTickLength () const

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

void	setSelected (bool on)
	设置是否选中

bool	isSelected () const
	是否选中

void	setSelectedPenWidthOffset (qreal offset=1)
	设置坐标轴在选中状态下的画笔宽度附加值

qreal	selectedPenWidthOffset () const
	获取当前坐标轴在选中状态下的画笔宽度附加值

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
	Calculate the extent.

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
	Draw a tick.

virtual void	drawBackbone (QPainter *painter) const =0
	Draws the baseline of the scale.

virtual void	drawLabel (QPainter *painter, double value) const =0
	Draws the label for a major scale tick.

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

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 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.

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

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

Draws the baseline of the scale.

Parameters

painter Painter

See also: drawTick(), drawLabel()

Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

◆ drawLabel()

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

protectedpure virtual

Draws the label for a major scale tick.

Parameters

painter	Painter
value	Value

See also: drawTick(), drawBackbone()

Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

◆ drawTick()

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

protectedpure virtual

Draw a tick.

Parameters

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

See also: drawBackbone(), drawLabel()

Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

◆ enableComponent()

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()

◆ extent()

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

pure virtual

Calculate the extent.

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

Parameters

font	Font used for drawing the tick labels

Returns: Number of pixels

See also: setMinimumExtent(), minimumExtent()

Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

◆ hasComponent()

bool QwtAbstractScaleDraw::hasComponent ( ScaleComponent component ) const

Check if a component is enabled.

Parameters

component Component type

Returns: true, when 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

是否选中

Returns

◆ 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

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

Returns: Scale pen width

See also: setPenWidth()

◆ scaleDiv()

const QwtScaleDiv & QwtAbstractScaleDraw::scaleDiv ( ) const

Returns: scale division

◆ scaleMap() [1/2]

QwtScaleMap & QwtAbstractScaleDraw::scaleMap ( )

Returns: Map how to translate between scale and pixel values

◆ scaleMap() [2/2]

const QwtScaleMap & QwtAbstractScaleDraw::scaleMap ( ) const

Returns: Map how to translate between scale and pixel values

◆ selectedPenWidthOffset()

qreal QwtAbstractScaleDraw::selectedPenWidthOffset ( ) const

获取当前坐标轴在选中状态下的画笔宽度附加值

Returns: 当前的宽度附加值。

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 (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()

◆ 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 )

Change the scale division.

Parameters

scaleDiv New scale division

◆ setSelected()

void QwtAbstractScaleDraw::setSelected ( bool on )

设置是否选中

Parameters

on

◆ setSelectedPenWidthOffset()

void QwtAbstractScaleDraw::setSelectedPenWidthOffset ( qreal offset = 1 )

设置坐标轴在选中状态下的画笔宽度附加值

当一个坐标轴（例如 X 轴或 Y 轴）被用户选中时，其绘制的画笔宽度会在原始宽度的基础上增加这个附加值，从而实现视觉上的突出显示效果。

Parameters

offset 选中时增加的宽度值（单位：像素）。该值应为非负数。如果为 0，则选中状态下的线宽与普通状态相同。

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 )

Change the transformation of the scale.

Parameters

transformation New scale transformation

◆ 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

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/qwt_abstract_scale_draw.h
/home/runner/work/QWT/QWT/src/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()