A class for drawing scales. More...

#include <qwt_scale_draw.h>

Inheritance diagram for QwtScaleDraw:

Public Types
enum	Alignment { BottomScale, TopScale, LeftScale, RightScale }
Public Member Functions
	QwtScaleDraw ()
virtual	~QwtScaleDraw ()
void	getBorderDistHint (const QFont &, int &start, int &end) const
int	minLabelDist (const QFont &) const
int	minLength (const QFont &) const
virtual double	extent (const QFont &) const
void	move (double x, double y)
void	move (const QPointF &)
void	setLength (double length)
Alignment	alignment () const
void	setAlignment (Alignment)
Qt::Orientation	orientation () const
QPointF	pos () const
double	length () const
void	setLabelAlignment (Qt::Alignment)
Qt::Alignment	labelAlignment () const
void	setLabelRotation (double rotation)
double	labelRotation () const
int	maxLabelHeight (const QFont &) const
int	maxLabelWidth (const QFont &) const
QPointF	labelPosition (double val) const
QRectF	labelRect (const QFont &, double val) const
QSizeF	labelSize (const QFont &, double val) const
QRect	boundingLabelRect (const QFont &, double val) const
Protected Member Functions
QTransform	labelTransformation (const QPointF &, const QSizeF &) const
virtual void	drawTick (QPainter *, double val, double len) const
virtual void	drawBackbone (QPainter *) const
virtual void	drawLabel (QPainter *, double val) const

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

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.

Constructor & Destructor Documentation

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.

QwtScaleDraw::~QwtScaleDraw ( ) [virtual]

Destructor.

Member Function Documentation

QwtScaleDraw::Alignment QwtScaleDraw::alignment ( ) const

Return alignment of the scale

See also:: setAlignment()

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

Find the bounding rect for the label. The coordinates of the rect are absolute coordinates ( calculated from pos() ). in direction of the tick.

Parameters:

font	Font used for painting
value	Value

See also:: labelRect()

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

Draws the baseline of the scale

Parameters:

painter Painter

See also:: drawTick(), drawLabel()

Implements QwtAbstractScaleDraw.

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

Draws the label for a major scale tick

Parameters:

painter	Painter
value	Value

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

Implements QwtAbstractScaleDraw.

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

Draw a tick

Parameters:

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

See also:: drawBackbone(), drawLabel()

Implements QwtAbstractScaleDraw.

double QwtScaleDraw::extent ( const QFont & font ) const [virtual]

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

See also:: minLength()

Implements QwtAbstractScaleDraw.

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

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

Qt::Alignment QwtScaleDraw::labelAlignment ( ) const

Returns:: the label flags

See also:: setLabelAlignment(), labelRotation()

QPointF QwtScaleDraw::labelPosition ( double value ) const

Find the position, where to paint a label

The position has a distance of majTickLength() + spacing() + 1 from the backbone. The direction depends on the alignment()

Parameters:

value Value

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

Find the bounding rect for the label. The coordinates of the rect are relative to spacing + ticklength from the backbone in direction of the tick.

Parameters:

font	Font used for painting
value	Value

double QwtScaleDraw::labelRotation ( ) const

Returns:: the label rotation

See also:: setLabelRotation(), labelAlignment()

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

Calculate the size that is needed to draw a label

Parameters:

font	Label font
value	Value

QTransform QwtScaleDraw::labelTransformation	(	const QPointF &	pos,
		const QSizeF &	size
	)		const `[protected]`

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

See also:: setLabelAlignment(), setLabelRotation()

double QwtScaleDraw::length ( ) const

Returns:: the length of the backbone

See also:: setLength(), pos()

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

Parameters:

font Font

Returns:: the maximum height of a label

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

Parameters:

font Font

Returns:: the maximum width of a label

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

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()

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

Calculate the minimum length that is needed to draw the scale

Parameters:

font	Font used for painting the labels

See also:: extent()

void QwtScaleDraw::move	(	double	x,
		double	y
	)		`[inline]`

Move the position of the scale

See also:: move(const QPointF &)

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()

Qt::Orientation QwtScaleDraw::orientation ( ) const

Return the orientation

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

See also:: alignment()

QPointF QwtScaleDraw::pos ( ) const

Returns:: Origin of the scale

See also:: move(), length()

void QwtScaleDraw::setAlignment ( Alignment align )

Set the alignment of the scale

The default alignment is QwtScaleDraw::BottomScale

See also:: alignment()

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

Change the label flags.

Labels are aligned to the point ticklength + 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().

void QwtScaleDraw::setLabelRotation ( double 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().

void QwtScaleDraw::setLength ( double length )

Set the length of the backbone.

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

See also:: move(), minLabelDist()

QwtScaleDraw Class Reference

Public Types

Public Member Functions

Protected Member Functions

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation