QwtAbstractScaleDraw Class Reference

A abstract base class for drawing scales. More...

#include <qwt_abstract_scale_draw.h>

Inheritance diagram for QwtAbstractScaleDraw:

Inheritance graph
[legend]

List of all members.

Public Types

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

Public Member Functions

virtual void draw (QPainter *, const QPalette &) const
void enableComponent (ScaleComponent, bool enable=true)
virtual double extent (const QFont &) const =0
bool hasComponent (ScaleComponent) const
virtual QwtText label (double) const
double maxTickLength () const
double minimumExtent () const
int penWidth () const
 QwtAbstractScaleDraw ()
const QwtScaleDivscaleDiv () const
QwtScaleMapscaleMap ()
const QwtScaleMapscaleMap () const
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 ~QwtAbstractScaleDraw ()

Protected Member Functions

virtual void drawBackbone (QPainter *painter) const =0
virtual void drawLabel (QPainter *painter, double value) const =0
virtual void drawTick (QPainter *painter, double value, double len) const =0
void invalidateCache ()
const QwtTexttickLabel (const QFont &, double value) const


Detailed Description

A abstract base class for drawing scales.

QwtAbstractScaleDraw can be used to draw linear or logarithmic scales.

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

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

QwtAbstractScaleDraw::QwtAbstractScaleDraw (  ) 

Constructor.

The range of the scale is initialized to [0, 100], The spacing (distance between ticks and labels) is set to 4, the tick lengths are set to 4,6 and 8 pixels

QwtAbstractScaleDraw::~QwtAbstractScaleDraw (  )  [virtual]

Destructor.


Member Function Documentation

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

Draw the scale.

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

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

Draws the baseline of the scale

Parameters:
painter Painter
See also:
drawTick(), drawLabel()

Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

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

Draws the label for a major scale tick

Parameters:
painter Painter
value Value
See also:
drawTick(), drawBackbone()

Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

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

Draw a tick

Parameters:
painter Painter
value Value of the tick
len Lenght of the tick
See also:
drawBackbone(), drawLabel()

Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

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

En/Disable a component of the scale

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

virtual double QwtAbstractScaleDraw::extent ( const QFont &   )  const [pure virtual]

Calculate the extent

The extent is the distcance from the baseline to the outermost pixel of the scale draw in opposite to its orientation. It is at least minimumExtent() pixels.

See also:
setMinimumExtent(), minimumExtent()

Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

bool QwtAbstractScaleDraw::hasComponent ( ScaleComponent  component  )  const

Check if a component is enabled

See also:
enableComponent()

void QwtAbstractScaleDraw::invalidateCache (  )  [protected]

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]

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.

double QwtAbstractScaleDraw::maxTickLength (  )  const

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

double QwtAbstractScaleDraw::minimumExtent (  )  const

Get the minimum extent

See also:
extent(), setMinimumExtent()

int QwtAbstractScaleDraw::penWidth (  )  const

Returns:
Scale pen width
See also:
setPenWidth()

Reimplemented in QwtDialScaleDraw.

const QwtScaleDiv & QwtAbstractScaleDraw::scaleDiv (  )  const

Returns:
scale division

QwtScaleMap & QwtAbstractScaleDraw::scaleMap (  ) 

Returns:
Map how to translate between scale and pixel values

const QwtScaleMap & QwtAbstractScaleDraw::scaleMap (  )  const

Returns:
Map how to translate between scale and pixel values

void QwtAbstractScaleDraw::setMinimumExtent ( double  minExtent  ) 

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  ) 

Specify the width of the scale pen.

Parameters:
width Pen width
See also:
penWidth()

void QwtAbstractScaleDraw::setScaleDiv ( const QwtScaleDiv sd  ) 

Change the scale division

Parameters:
sd New scale division

void QwtAbstractScaleDraw::setSpacing ( double  spacing  ) 

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 
)

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  ) 

Change the transformation of the scale

Parameters:
transformation New scale transformation

double QwtAbstractScaleDraw::spacing (  )  const

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]

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

Return the length of the ticks

See also:
setTickLength(), maxTickLength()


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