A class for drawing scales. More...

#include <qwt_scale_draw.h>

Inheritance diagram for QwtScaleDraw:

Classes
struct	CornerTargets
	Corner miter target positions in device coordinates. More...

class	PrivateData

Public Types
enum	Alignment { BottomScale , TopScale , LeftScale , RightScale }
	Alignment of the scale draw. More...

enum	CornerMiterFlag { NoMiter = 0x0 , MiterAtStart = 0x1 , MiterAtEnd = 0x2 }
	Corner miter flags. More...

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

Public Member Functions
	QwtScaleDraw ()
	Constructor.

void	setCornerMiter (CornerMiter miter)
	Set the corner miter flags.

CornerMiter	cornerMiter () const
	Get the corner miter flags.

void	setCornerTargets (const CornerTargets &targets)
	Set the corner miter target positions (device coordinates)

CornerTargets	cornerTargets () const
	Get the corner miter target positions.

void	getBorderDistHint (const QFont &, int &start, int &end) const
	Get the border distance hint.

int	minLabelDist (const QFont &) const
	Get the minimum label distance.

int	minLength (const QFont &) const
	Get the minimum length.

virtual double	extent (const QFont &) const override
	Calculate the width/height that is needed for a vertical/horizontal scale.

void	move (double x, double y)
	Move the position of the scale.

void	move (const QPointF &)
	Move the position of the scale.

void	setLength (double length)
	Set the length of the backbone.

Alignment	alignment () const
	Return alignment of the scale.

void	setAlignment (Alignment)
	Set the alignment.

Qt::Orientation	orientation () const
	Return the orientation.

QPointF	pos () const
	Get origin of the scale.

double	length () const
	Get the length of the backbone.

void	setLabelAlignment (Qt::Alignment)
	Set the label alignment.

Qt::Alignment	labelAlignment () const
	Get the label flags.

void	setLabelRotation (double rotation)
	Set the label rotation.

double	labelRotation () const
	Get the label rotation.

int	maxLabelHeight (const QFont &) const
	Get the maximum label height.

int	maxLabelWidth (const QFont &) const
	Get the maximum label width.

QPointF	labelPosition (double value) const
	Get the label position for a value.

QRectF	labelRect (const QFont &, double value) const
	Get the label rectangle for a value.

QSizeF	labelSize (const QFont &, double value) const
	Get the label size for a value.

QRect	boundingLabelRect (const QFont &, double value) const
	Get the bounding label rectangle.

void	drawTicksInside (QPainter *, const QRectF &canvasRect, const QwtScaleMap &) const
	Draw the ticks from the edges of a canvas towards its interior.

Public Member Functions inherited from QwtAbstractScaleDraw
	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.

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
QTransform	labelTransformation (const QPointF &, const QSizeF &) const
	Calculate the transformation that is needed to paint a label.

virtual void	drawTick (QPainter *, double value, double len) const override
	Draw a tick.

virtual void	drawBackbone (QPainter *) const override
	Draws the baseline of the scale.

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

Protected Member Functions inherited from QwtAbstractScaleDraw
const QwtText &	tickLabel (const QFont &, double value) const
	Convert a value into its representing label and cache it.

qreal	effectivePenWidthF () const
	Pen width including the offset of the selected state.

Detailed Description

A class for drawing scales.

QwtScaleDraw can be used to draw linear or logarithmic scales. A scale has a position, an alignment and a length, which can be specified. The labels can be rotated and aligned to the ticks using setLabelRotation() and setLabelAlignment().

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

◆ Alignment

enum QwtScaleDraw::Alignment

Alignment of the scale draw.

See also: setAlignment(), alignment()

Enumerator
BottomScale	The scale is below.
TopScale	The scale is above.
LeftScale	The scale is left.
RightScale	The scale is right.

◆ CornerMiterFlag

enum QwtScaleDraw::CornerMiterFlag

Corner miter flags.

When a miter flag is set, the backbone is extended beyond the corresponding end of the scale into a corner shared with a perpendicular scale, so that both backbones intersect instead of ending in a diagonal step. The extension reaches the far edge of the perpendicular backbone band closest to the canvas when a target has been set with setCornerTargets(), so that the whole corner square is covered for any pen width; otherwise it falls back to one pixel beyond the end of the scale. For vertical scales AtStart/AtEnd refer to the top/bottom end, for horizontal scales to the left/right end.

See also: setCornerMiter(), cornerMiter(), setCornerTargets()

Enumerator
NoMiter	Do not extend the backbone.
MiterAtStart	Extend the backbone beyond the start of the scale.
MiterAtEnd	Extend the backbone beyond the end of the scale.

Constructor & Destructor Documentation

◆ QwtScaleDraw()

QwtScaleDraw::QwtScaleDraw ( )

Constructor.

The range of the scale is initialized to [0, 100], the position is at (0, 0) with a length of 100. The orientation is QwtAbstractScaleDraw::Bottom.

Member Function Documentation

◆ alignment()

QwtScaleDraw::Alignment QwtScaleDraw::alignment ( ) const

Return alignment of the scale.

Returns: the alignment; Alignment of the scale

See also: setAlignment()

◆ boundingLabelRect()

QRect QwtScaleDraw::boundingLabelRect	(	const QFont &	font,
		double	value
	)		const

Get the bounding label rectangle.

Find the bounding rectangle for the label.

The coordinates of the rectangle are absolute ( calculated from pos() ) in direction of the tick.

Parameters

font	Font used for painting
value	Value

Returns: Bounding rectangle

See also: labelRect()

◆ cornerMiter()

QwtScaleDraw::CornerMiter QwtScaleDraw::cornerMiter ( ) const

Get the corner miter flags.

Returns: the corner miter flags; Flags specifying which ends of the backbone are extended

See also: setCornerMiter()

◆ cornerTargets()

QwtScaleDraw::CornerTargets QwtScaleDraw::cornerTargets ( ) const

Get the corner miter target positions.

Returns: the corner miter target positions; Target positions in device coordinates, qQNaN() when unset

See also: setCornerTargets()

◆ drawBackbone()

void QwtScaleDraw::drawBackbone ( QPainter * painter ) const

overrideprotectedvirtual

Draws the baseline of the scale.

Parameters

painter Painter

See also: drawTick(), drawLabel()

Implements QwtAbstractScaleDraw.

◆ drawLabel()

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

overrideprotectedvirtual

Draws the label for a major scale tick.

Parameters

painter	Painter
value	Value

See also: drawTick(), drawBackbone(), boundingLabelRect()

Implements QwtAbstractScaleDraw.

◆ drawTick()

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

overrideprotectedvirtual

Draw a tick.

Parameters

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

See also: drawBackbone(), drawLabel()

Implements QwtAbstractScaleDraw.

◆ drawTicksInside()

void QwtScaleDraw::drawTicksInside	(	QPainter *	painter,
		const QRectF &	canvasRect,
		const QwtScaleMap &	map
	)		const

Draw the ticks from the edges of a canvas towards its interior.

Parameters

painter	Painter
canvasRect	Canvas rectangle in painter coordinates
map	Scale map of the axis on the canvas

Used by QwtPlot for axes with QwtPlot::TickInside. The ticks start at the canvas edge adjacent to the backbone band and grow into the canvas, following the same device pixel rules as the backbone and the outside ticks of draw(): the thickness is qMax( 1, round( pen width ) ) device pixels without being scaled by the device pixel ratio, and every tick is aligned to the device pixel grid. Stroking a pen of a fractional logical width instead would make the ticks thicker than the backbone at device pixel ratios above one and rasterize ticks at different subpixel positions with different widths.

See also: drawTick()

◆ extent()

double QwtScaleDraw::extent ( const QFont & font ) const

overridevirtual

Calculate the width/height that is needed for a vertical/horizontal scale.

The extent is calculated from the pen width of the backbone, the major tick length, the spacing and the maximum width/height of the labels.

Parameters

font	Font used for painting the labels

Returns: Extent

See also: minLength()

Implements QwtAbstractScaleDraw.

◆ getBorderDistHint()

void QwtScaleDraw::getBorderDistHint	(	const QFont &	font,
		int &	start,
		int &	end
	)		const

Get the border distance hint.

Determine the minimum border distance.

This member function returns the minimum space needed to draw the mark labels at the scale's endpoints.

Parameters

font	Font
start	Start border distance
end	End border distance

◆ labelAlignment()

Qt::Alignment QwtScaleDraw::labelAlignment ( ) const

Get the label flags.

Returns: the label alignment; the label flags

See also: setLabelAlignment(), labelRotation()

◆ labelPosition()

QPointF QwtScaleDraw::labelPosition ( double value ) const

Get the label position for a value.

Find the position, where to paint a label.

The position has a distance that depends on the length of the ticks in direction of the alignment().

Parameters

value Value

Returns: Position, where to paint a label

◆ labelRect()

QRectF QwtScaleDraw::labelRect	(	const QFont &	font,
		double	value
	)		const

Get the label rectangle for a value.

Find the bounding rectangle for the label.

The coordinates of the rectangle are relative to spacing + tick length from the backbone in direction of the tick.

Parameters

font	Font used for painting
value	Value

Returns: Bounding rectangle that is needed to draw a label

◆ labelRotation()

double QwtScaleDraw::labelRotation ( ) const

Get the label rotation.

Returns: the label rotation; the label rotation

See also: setLabelRotation(), labelAlignment()

◆ labelSize()

QSizeF QwtScaleDraw::labelSize	(	const QFont &	font,
		double	value
	)		const

Get the label size for a value.

Calculate the size that is needed to draw a label.

Parameters

font	Label font
value	Value

Returns: Size that is needed to draw a label

◆ labelTransformation()

QTransform QwtScaleDraw::labelTransformation	(	const QPointF &	pos,
		const QSizeF &	size
	)		const

protected

Calculate the transformation that is needed to paint a label.

Calculate the transformation that is needed to paint a label depending on its alignment and rotation.

Parameters

pos	Position where to paint the label
size	Size of the label

Returns: Transformation matrix

See also: setLabelAlignment(), setLabelRotation()

◆ length()

double QwtScaleDraw::length ( ) const

Get the length of the backbone.

Returns: the length; the length of the backbone

See also: setLength(), pos()

◆ maxLabelHeight()

int QwtScaleDraw::maxLabelHeight ( const QFont & font ) const

Get the maximum label height.

Get the maximum height of a label.

Parameters

font Font

Returns: the maximum height of a label

◆ maxLabelWidth()

int QwtScaleDraw::maxLabelWidth ( const QFont & font ) const

Get the maximum label width.

Get the maximum width of a label.

Parameters

font Font

Returns: the maximum width of a label

◆ minLabelDist()

int QwtScaleDraw::minLabelDist ( const QFont & font ) const

Get the minimum label distance.

Determine the minimum distance between two labels.

Determine the minimum distance between two labels, that is necessary that the texts don't overlap.

Parameters

font Font

Returns: The maximum width of a label

See also: getBorderDistHint()

◆ minLength()

int QwtScaleDraw::minLength ( const QFont & font ) const

Get the minimum length.

Calculate the minimum length that is needed to draw the scale.

Parameters

font	Font used for painting the labels

Returns: Minimum length that is needed to draw the scale

See also: extent()

◆ move() [1/2]

void QwtScaleDraw::move ( const QPointF & pos )

Move the position of the scale.

The meaning of the parameter pos depends on the alignment:

QwtScaleDraw::LeftScale: The origin is the topmost point of the backbone. The backbone is a vertical line. Scale marks and labels are drawn at the left of the backbone.
QwtScaleDraw::RightScale: The origin is the topmost point of the backbone. The backbone is a vertical line. Scale marks and labels are drawn at the right of the backbone.
QwtScaleDraw::TopScale: The origin is the leftmost point of the backbone. The backbone is a horizontal line. Scale marks and labels are drawn above the backbone.
QwtScaleDraw::BottomScale: The origin is the leftmost point of the backbone. The backbone is a horizontal line. Scale marks and labels are drawn below the backbone.

Parameters

pos	Origin of the scale

See also: pos(), setLength()

◆ move() [2/2]

void QwtScaleDraw::move	(	double	x,
		double	y
	)

inline

Move the position of the scale.

Parameters

x	X coordinate
y	Y coordinate

See also: move(const QPointF&)

◆ orientation()

Qt::Orientation QwtScaleDraw::orientation ( ) const

Return the orientation.

Returns: the orientation

TopScale, BottomScale are horizontal (Qt::Horizontal) scales, LeftScale, RightScale are vertical (Qt::Vertical) scales.

Returns: Orientation of the scale

See also: alignment()

◆ pos()

QPointF QwtScaleDraw::pos ( ) const

Get origin of the scale.

Returns: the position; Origin of the scale

See also: move(), length()

◆ setAlignment()

void QwtScaleDraw::setAlignment ( Alignment align )

Set the alignment.

Set the alignment of the scale.

Parameters

align Alignment of the scale

The default alignment is QwtScaleDraw::BottomScale

See also: alignment()

◆ setCornerMiter()

void QwtScaleDraw::setCornerMiter ( CornerMiter miter )

Set the corner miter flags.

Parameters

miter Flags specifying which ends of the backbone are extended into a corner shared with a perpendicular scale

QwtScaleWidget sets the flags from the visibility of the perpendicular axes of the plot; standalone use keeps NoMiter.

See also: cornerMiter()

◆ setCornerTargets()

void QwtScaleDraw::setCornerTargets ( const CornerTargets & targets )

Set the corner miter target positions (device coordinates)

Set the corner miter target positions.

Parameters

targets Target positions in device coordinates

When a miter flag is set and its target is valid, the backbone is extended exactly to that position instead of one pixel beyond the end of the scale; border ticks snap to the same target. The target is the near edge of the perpendicular backbone band closest to the canvas. QwtScaleWidget and QwtPlotRenderer compute the targets from the geometry of the perpendicular axes; standalone use keeps them unset and the historical fallback.

See also: setCornerMiter(), cornerTargets(), CornerTargets

◆ setLabelAlignment()

void QwtScaleDraw::setLabelAlignment ( Qt::Alignment alignment )

Set the label alignment.

Change the label flags.

Labels are aligned to the point tick length + spacing away from the backbone.

The alignment is relative to the orientation of the label text. In case of an flags of 0 the label will be aligned depending on the orientation of the scale:

QwtScaleDraw::TopScale: Qt::AlignHCenter | Qt::AlignTop
QwtScaleDraw::BottomScale: Qt::AlignHCenter | Qt::AlignBottom
QwtScaleDraw::LeftScale: Qt::AlignLeft | Qt::AlignVCenter
QwtScaleDraw::RightScale: Qt::AlignRight | Qt::AlignVCenter

Changing the alignment is often necessary for rotated labels.

Parameters

alignment Or'd Qt::AlignmentFlags see <qnamespace.h>

See also: setLabelRotation(), labelRotation(), labelAlignment()

Warning: The various alignments might be confusing. The alignment of the label is not the alignment of the scale and is not the alignment of the flags ( QwtText::flags() ) returned from QwtAbstractScaleDraw::label().

◆ setLabelRotation()

void QwtScaleDraw::setLabelRotation ( double rotation )

Set the label rotation.

Rotate all labels.

When changing the rotation, it might be necessary to adjust the label flags too. Finding a useful combination is often the result of try and error.

Parameters

rotation Angle in degrees. When changing the label rotation, the label flags often needs to be adjusted too.

See also: setLabelAlignment(), labelRotation(), labelAlignment()

◆ setLength()

void QwtScaleDraw::setLength ( double length )

Set the length of the backbone.

The length doesn't include the space needed for overlapping labels.

Parameters

length Length of the backbone

See also: move(), minLabelDist()

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

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

Classes

Public Types

Public Member Functions

Protected Member Functions

Detailed Description

Member Enumeration Documentation

◆ Alignment

◆ CornerMiterFlag

Constructor & Destructor Documentation

◆ QwtScaleDraw()

Member Function Documentation

◆ alignment()

◆ boundingLabelRect()

◆ cornerMiter()

◆ cornerTargets()

◆ drawBackbone()

◆ drawLabel()

◆ drawTick()

◆ drawTicksInside()

◆ extent()

◆ getBorderDistHint()

◆ labelAlignment()

◆ labelPosition()

◆ labelRect()

◆ labelRotation()

◆ labelSize()

◆ labelTransformation()

◆ length()

◆ maxLabelHeight()

◆ maxLabelWidth()

◆ minLabelDist()

◆ minLength()

◆ move() [1/2]

◆ move() [2/2]

◆ orientation()

◆ pos()

◆ setAlignment()

◆ setCornerMiter()

◆ setCornerTargets()

◆ setLabelAlignment()

◆ setLabelRotation()

◆ setLength()