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
}
enum  ScaleComponent {
  Backbone = 0x01,
  Ticks = 0x02,
  Labels = 0x04
}
typedef QFlags< ScaleComponentScaleComponents

Public Member Functions

Alignment alignment () const
QRect boundingLabelRect (const QFont &, double val) const
virtual void draw (QPainter *, const QPalette &) const
void enableComponent (ScaleComponent, bool enable=true)
virtual double extent (const QFont &) const
void getBorderDistHint (const QFont &, int &start, int &end) const
bool hasComponent (ScaleComponent) const
virtual QwtText label (double) 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
double maxTickLength () const
double minimumExtent () const
int minLabelDist (const QFont &) const
int minLength (const QFont &) const
void move (const QPointF &)
void move (double x, double y)
Qt::Orientation orientation () const
int penWidth () const
QPointF pos () const
 QwtScaleDraw ()
const QwtScaleDivscaleDiv () const
QwtScaleMapscaleMap ()
const QwtScaleMapscaleMap () const
void setAlignment (Alignment)
void setLabelAlignment (Qt::Alignment)
void setLabelRotation (double rotation)
void setLength (double length)
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
virtual ~QwtScaleDraw ()

Protected Member Functions

virtual void drawBackbone (QPainter *) const
virtual void drawLabel (QPainter *, double val) const
virtual void drawTick (QPainter *, double val, double len) const
void invalidateCache ()
QTransform labelTransformation (const QPointF &, const QSizeF &) const
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 Typedef Documentation

Scale components.


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.

Components of a scale

See also:
enableComponent(), hasComponent
Enumerator:
Backbone  Backbone = the line where the ticks are located.
Ticks  Ticks.
Labels  Labels.


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 QwtAbstractScaleDraw::draw ( QPainter *  painter,
const QPalette &  palette 
) const [virtual, inherited]

Draw the scale.

Parameters:
painter The painter
palette Palette, text color is used for the labels, foreground color for ticks and backbone

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.

void QwtAbstractScaleDraw::enableComponent ( ScaleComponent  component,
bool  enable = true 
) [inherited]

En/Disable a component of the scale

Parameters:
component Scale component
enable On/Off
See also:
hasComponent()

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

bool QwtAbstractScaleDraw::hasComponent ( ScaleComponent  component  )  const [inherited]

Check if a component is enabled

See also:
enableComponent()

void QwtAbstractScaleDraw::invalidateCache (  )  [protected, inherited]

Invalidate the cache used by QwtAbstractScaleDraw::tickLabel

The cache is invalidated, when a new QwtScaleDiv is set. If the labels need to be changed. while the same QwtScaleDiv is set, invalidateCache() needs to be called manually.

QwtText QwtAbstractScaleDraw::label ( double  value  )  const [virtual, inherited]

Convert a value into its representing label.

The value is converted to a plain text using QLocale::system().toString(value). This method is often overloaded by applications to have individual labels.

Parameters:
value Value
Returns:
Label string.

Reimplemented in QwtDialScaleDraw.

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

double QwtAbstractScaleDraw::maxTickLength (  )  const [inherited]

Returns:
Length of the longest tick
Useful for layout calculations
See also:
tickLength(), setTickLength()

double QwtAbstractScaleDraw::minimumExtent (  )  const [inherited]

Get the minimum extent

See also:
extent(), setMinimumExtent()

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 ( 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()

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

Move the position of the scale

See also:
move(const QPointF &)

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()

int QwtAbstractScaleDraw::penWidth (  )  const [inherited]

Returns:
Scale pen width
See also:
setPenWidth()

Reimplemented in QwtDialScaleDraw.

QPointF QwtScaleDraw::pos (  )  const

Returns:
Origin of the scale
See also:
move(), length()

const QwtScaleDiv & QwtAbstractScaleDraw::scaleDiv (  )  const [inherited]

Returns:
scale division

QwtScaleMap & QwtAbstractScaleDraw::scaleMap (  )  [inherited]

Returns:
Map how to translate between scale and pixel values

const QwtScaleMap & QwtAbstractScaleDraw::scaleMap (  )  const [inherited]

Returns:
Map how to translate between scale and pixel values

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()

void QwtAbstractScaleDraw::setMinimumExtent ( double  minExtent  )  [inherited]

Set a minimum for the extent.

The extent is calculated from the coomponents of the scale draw. In situations, where the labels are changing and the layout depends on the extent (f.e scrolling a scale), setting an upper limit as minimum extent will avoid jumps of the layout.

Parameters:
minExtent Minimum extent
See also:
extent(), minimumExtent()

void QwtAbstractScaleDraw::setPenWidth ( int  width  )  [inherited]

Specify the width of the scale pen.

Parameters:
width Pen width
See also:
penWidth()

void QwtAbstractScaleDraw::setScaleDiv ( const QwtScaleDiv sd  )  [inherited]

Change the scale division

Parameters:
sd New scale division

void QwtAbstractScaleDraw::setSpacing ( double  spacing  )  [inherited]

Set the spacing between tick and labels.

The spacing is the distance between ticks and labels. The default spacing is 4 pixels.

Parameters:
spacing Spacing
See also:
spacing()

void QwtAbstractScaleDraw::setTickLength ( QwtScaleDiv::TickType  tickType,
double  length 
) [inherited]

Set the length of the ticks

Parameters:
tickType Tick type
length New length
Warning:
the length is limited to [0..1000]

void QwtAbstractScaleDraw::setTransformation ( QwtScaleTransformation transformation  )  [inherited]

Change the transformation of the scale

Parameters:
transformation New scale transformation

double QwtAbstractScaleDraw::spacing (  )  const [inherited]

Get the spacing.

The spacing is the distance between ticks and labels. The default spacing is 4 pixels.

See also:
setSpacing()

const QwtText & QwtAbstractScaleDraw::tickLabel ( const QFont &  font,
double  value 
) const [protected, inherited]

Convert a value into its representing label and cache it.

The conversion between value and label is called very often in the layout and painting code. Unfortunately the calculation of the label sizes might be slow (really slow for rich text in Qt4), so it's necessary to cache the labels.

Parameters:
font Font
value Value
Returns:
Tick label

double QwtAbstractScaleDraw::tickLength ( QwtScaleDiv::TickType  tickType  )  const [inherited]

Return the length of the ticks

See also:
setTickLength(), maxTickLength()


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