QwtScaleDraw Class Reference

A class for drawing scales. More...

#include <qwt_scale_draw.h>

Inheritance diagram for QwtScaleDraw:
Inheritance graph
[legend]

List of all members.

Public Types

enum  Alignment {
  BottomScale,
  TopScale,
  LeftScale,
  RightScale
}

Public Member Functions

 QwtScaleDraw ()
 QwtScaleDraw (const QwtScaleDraw &)
virtual ~QwtScaleDraw ()
QwtScaleDrawoperator= (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

Alignment 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 (  )  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,
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 (  )  const
Returns:
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  )  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
QRect 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()
QSize QwtScaleDraw::labelSize ( const QFont &  font,
double  value 
) const

Calculate the size that is needed to draw a label

Parameters:
font Label font
value Value
int 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 QPen &  pen,
const QFont &  font 
) const

Calculate 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 (  )  const

Return the orientation

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

See also:
alignment()
QPoint 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 ( int  length  ) 

Set the length of the backbone.

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

See also:
move(), minLabelDist()
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