Qwt User's Guide  6.0.2
Public Types | Public Member Functions | Protected Member Functions
QwtScaleDraw Class Reference

#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 Types inherited from QwtAbstractScaleDraw
enum  ScaleComponent {
  Backbone = 0x01,
  Ticks = 0x02,
  Labels = 0x04
}
typedef QFlags< ScaleComponentScaleComponents

Public Member Functions

 QwtScaleDraw ()
virtual ~QwtScaleDraw ()
Alignment alignment () const
QRect boundingLabelRect (const QFont &, double val) const
virtual double extent (const QFont &) const
void getBorderDistHint (const QFont &, int &start, int &end) const
Qt::Alignment labelAlignment () const
QPointF labelPosition (double val) const
QRectF labelRect (const QFont &, double val) const
double labelRotation () const
QSizeF labelSize (const QFont &, double val) const
double length () const
int maxLabelHeight (const QFont &) const
int maxLabelWidth (const QFont &) const
int minLabelDist (const QFont &) const
int minLength (const QFont &) const
void move (double x, double y)
void move (const QPointF &)
Qt::Orientation orientation () const
QPointF pos () const
void setAlignment (Alignment)
void setLabelAlignment (Qt::Alignment)
void setLabelRotation (double rotation)
void setLength (double length)
- Public Member Functions inherited from QwtAbstractScaleDraw
 QwtAbstractScaleDraw ()
virtual ~QwtAbstractScaleDraw ()
virtual void draw (QPainter *, const QPalette &) const
void enableComponent (ScaleComponent, bool enable=true)
bool hasComponent (ScaleComponent) const
virtual QwtText label (double) const
double maxTickLength () const
double minimumExtent () const
int penWidth () const
const QwtScaleDivscaleDiv () const
const QwtScaleMapscaleMap () const
QwtScaleMapscaleMap ()
void setMinimumExtent (double)
void setPenWidth (int width)
void setScaleDiv (const QwtScaleDiv &s)
void setSpacing (double margin)
void setTickLength (QwtScaleDiv::TickType, double length)
void setTransformation (QwtScaleTransformation *)
double spacing () const
double tickLength (QwtScaleDiv::TickType) const

Protected Member Functions

virtual void drawBackbone (QPainter *) const
virtual void drawLabel (QPainter *, double val) const
virtual void drawTick (QPainter *, double val, double len) const
QTransform labelTransformation (const QPointF &, const QSizeF &) const
- Protected Member Functions inherited from QwtAbstractScaleDraw
void invalidateCache ()
const QwtTexttickLabel (const QFont &, double value) 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()
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.


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:
fontFont used for painting
valueValue
See also:
labelRect()
void QwtScaleDraw::drawBackbone ( QPainter *  painter) const
protectedvirtual

Draws the baseline of the scale

Parameters:
painterPainter
See also:
drawTick(), drawLabel()

Implements QwtAbstractScaleDraw.

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

Draws the label for a major scale tick

Parameters:
painterPainter
valueValue
See also:
drawTick(), drawBackbone(), boundingLabelRect()

Implements QwtAbstractScaleDraw.

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

Draw a tick

Parameters:
painterPainter
valueValue of the tick
lenLenght 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:
fontFont 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:
fontFont
startStart border distance
endEnd 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:
valueValue
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:
fontFont used for painting
valueValue
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:
fontLabel font
valueValue
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:
posPosition where to paint the label
sizeSize 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:
fontFont
Returns:
the maximum height of a label
int QwtScaleDraw::maxLabelWidth ( const QFont &  font) const
Parameters:
fontFont
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:
fontFont
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:
fontFont 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:
posOrigin 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\n
QwtScaleDraw::BottomScale: Qt::AlignHCenter | Qt::AlignBottom\n
QwtScaleDraw::LeftScale: Qt::AlignLeft | Qt::AlignVCenter\n
QwtScaleDraw::RightScale: Qt::AlignRight | Qt::AlignVCenter\n

Changing the alignment is often necessary for rotated labels.

Parameters:
alignmentOr'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:
rotationAngle 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()