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QwtScaleDraw

NAME

QwtScaleDraw -

A class for drawing scales.

SYNOPSIS

#include <qwt_scale_draw.h>

Inherits QwtAbstractScaleDraw.

Public Types

enum Alignment { BottomScale, TopScale, LeftScale, RightScale }

Public Member Functions

QwtScaleDraw ()

QwtScaleDraw (const QwtScaleDraw &)

virtual ~QwtScaleDraw ()

QwtScaleDraw & operator= (const QwtScaleDraw &other)

void getBorderDistHint (const QFont &, int &start, int &end) const

int minLabelDist (const QFont &) const

int minLength (const QPen &, const QFont &) const

virtual int extent (const QPen &, const QFont &) const

void move (int x, int y)

void move (const QPoint &)

void setLength (int length)

Alignment alignment () const

void setAlignment (Alignment)

Qt::Orientation orientation () const

QPoint pos () const

int 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

QPoint labelPosition (double val) const

QRect labelRect (const QFont &, double val) const

QSize labelSize (const QFont &, double val) const

QRect boundingLabelRect (const QFont &, double val) const

Protected Member Functions

QMatrix labelMatrix (const QPoint &, const QSize &) const

virtual void drawTick (QPainter *p, double val, int len) const

virtual void drawBackbone (QPainter *p) const

virtual void drawLabel (QPainter *p, 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::AlignmentAlignment of the scale draw

See also:

setAlignment(), alignment()

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 (const QwtScaleDraw & other)

Copy constructor.

QwtScaleDraw::~QwtScaleDraw () [virtual]

Destructor.

Member Function Documentation

QwtScaleDraw::Alignment QwtScaleDraw::alignment () constReturn alignment of the scale

See also:

setAlignment()

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

int QwtScaleDraw::extent (const QPen & pen, 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:

pen Pen that is used for painting backbone and ticks
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 () constReturns:

the label flags

See also:

setLabelAlignment(), labelRotation()

QMatrix QwtScaleDraw::labelMatrix (const QPoint & pos, const QSize & size) const [protected]Calculate the matrix 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()

QPoint QwtScaleDraw::labelPosition (double value) constFind 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

QRect QwtScaleDraw::labelRect (const QFont & font, double value) constFind 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 () constReturns:

the label rotation

See also:

setLabelRotation(), labelAlignment()

QSize QwtScaleDraw::labelSize (const QFont & font, double value) constCalculate the size that is needed to draw a label

Parameters:

font Label font
value Value

int QwtScaleDraw::length () constReturns:

the length of the backbone

See also:

setLength(), pos()

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

font Font

Returns:

the maximum height of a label

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

font Font

Returns:

the maximum width of a label

int QwtScaleDraw::minLabelDist (const QFont & font) constDetermine 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 QPen & pen, const QFont & font) constCalculate the minimum length that is needed to draw the scale

Parameters:

pen Pen that is used for painting backbone and ticks
font Font used for painting the labels

See also:

extent()

void QwtScaleDraw::move (const QPoint & 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()

void QwtScaleDraw::move (int x, int y) [inline]Move the position of the scale

See also:

move(const QPoint &)

QwtScaleDraw & QwtScaleDraw::operator= (const QwtScaleDraw & other)

Assignment operator.

Qt::Orientation QwtScaleDraw::orientation () constReturn the orientation

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

See also:

alignment()

QPoint QwtScaleDraw::pos () constReturns:

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 (int length)Set the length of the backbone.

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

See also:

move(), minLabelDist()

Author

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