NAME
QwtAbstractScaleDraw - A abstract base class for drawing scales.
SYNOPSIS
#include <qwt_abstract_scale_draw.h>
Inherited by QwtRoundScaleDraw, and QwtScaleDraw.
Public Types
enum ScaleComponent { Backbone = 1, Ticks = 2, Labels = 4 }
Public Member Functions
QwtAbstractScaleDraw ()
QwtAbstractScaleDraw (const QwtAbstractScaleDraw &)
virtual ~QwtAbstractScaleDraw ()
QwtAbstractScaleDraw & operator= (const QwtAbstractScaleDraw &)
void setScaleDiv (const QwtScaleDiv &s)
const QwtScaleDiv & scaleDiv () const
void setTransformation (QwtScaleTransformation *)
const QwtScaleMap & map () const
void enableComponent (ScaleComponent, bool enable=true)
bool hasComponent (ScaleComponent) const
void setTickLength (QwtScaleDiv::TickType, int length)
int tickLength (QwtScaleDiv::TickType) const
int majTickLength () const
void setSpacing (int margin)
int spacing () const
virtual void draw (QPainter *, const QPalette &) const
virtual QwtText label (double) const
virtual int extent (const QPen &, const QFont &) const =0
void setMinimumExtent (int)
int minimumExtent () const
QwtScaleMap & scaleMap ()
Protected Member Functions
virtual void drawTick (QPainter *painter, double value, int len) const
=0
virtual void drawBackbone (QPainter *painter) const =0
virtual void drawLabel (QPainter *painter, double value) const =0
void invalidateCache ()
const QwtText & tickLabel (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 Enumeration Documentation
enum QwtAbstractScaleDraw::ScaleComponent
Components of a scale
· Backbone
· Ticks
· Labels
See also:
enableComponent(), hasComponent
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 (const QwtAbstractScaleDraw &
other)
Copy constructor.
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, int 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 int QwtAbstractScaleDraw::extent (const QPen &, 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,
QwtAbstractScaleDraw::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.
int QwtAbstractScaleDraw::majTickLength () const
The same as QwtAbstractScaleDraw::tickLength(QwtScaleDiv::MajorTick).
const QwtScaleMap & QwtAbstractScaleDraw::map () const
Returns:
Map how to translate between scale and pixel values
int QwtAbstractScaleDraw::minimumExtent () const
Get the minimum extent
See also:
extent(), setMinimumExtent()
QwtAbstractScaleDraw & QwtAbstractScaleDraw::operator= (const
QwtAbstractScaleDraw & other)
Assignment operator.
const QwtScaleDiv & QwtAbstractScaleDraw::scaleDiv () const
Returns:
scale division
QwtScaleMap & QwtAbstractScaleDraw::scaleMap ()
Returns:
Map how to translate between scale and pixel values
void QwtAbstractScaleDraw::setMinimumExtent (int 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::setScaleDiv (const QwtScaleDiv & sd)
Change the scale division
Parameters:
sd New scale division
void QwtAbstractScaleDraw::setSpacing (int 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,
int 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
int 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
int QwtAbstractScaleDraw::tickLength (QwtScaleDiv::TickType tickType) const
Return the length of the ticks
See also:
setTickLength(), majTickLength()
Author
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