Provided by: libqwt5-doc_5.2.3-1_all 
NAME
QwtAbstractScaleDraw -
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 ()
virtual void draw (QPainter *, const QPalette &) const
void enableComponent (ScaleComponent, bool enable=true)
virtual int extent (const QPen &, const QFont &) const =0
bool hasComponent (ScaleComponent) const
virtual QwtText label (double) const
int majTickLength () const
const QwtScaleMap & map () const
int minimumExtent () const
QwtAbstractScaleDraw & operator= (const QwtAbstractScaleDraw &)
const QwtScaleDiv & scaleDiv () const
QwtScaleMap & scaleMap ()
void setMinimumExtent (int)
void setScaleDiv (const QwtScaleDiv &s)
void setSpacing (int margin)
void setTickLength (QwtScaleDiv::TickType, int length)
void setTransformation (QwtScaleTransformation *)
int spacing () const
int tickLength (QwtScaleDiv::TickType) const
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, int len) 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
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 QwtScaleDraw, and QwtRoundScaleDraw.
virtual void QwtAbstractScaleDraw::drawLabel (QPainter *painter, doublevalue) const
[protected], [pure virtual]
Draws the label for a major scale tick
Parameters:
painter Painter
value Value
See also:
drawTick, drawBackbone
Implemented in QwtScaleDraw, and QwtRoundScaleDraw.
virtual void QwtAbstractScaleDraw::drawTick (QPainter *painter, doublevalue, intlen) const
[protected], [pure virtual]
Draw a tick
Parameters:
painter Painter
value Value of the tick
len Length of the tick
See also:
drawBackbone(), drawLabel()
Implemented in QwtScaleDraw, and QwtRoundScaleDraw.
void QwtAbstractScaleDraw::enableComponent (ScaleComponentcomponent, boolenable = 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 (ScaleComponentcomponent) 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 (doublevalue) 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()
const QwtScaleDiv & QwtAbstractScaleDraw::scaleDiv () const
Returns:
scale division
QwtScaleMap & QwtAbstractScaleDraw::scaleMap ()
Returns:
Map how to translate between scale and pixel values
void QwtAbstractScaleDraw::setMinimumExtent (intminExtent)
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 (intspacing)
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::TickTypetickType, intlength)
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, doublevalue) 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::TickTypetickType) const
Return the length of the ticks
See also:
setTickLength(), majTickLength()
Author
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