Provided by: libqwt-doc_6.1.4-2_all 
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 = 0x01, Ticks = 0x02, Labels = 0x04 }
typedef QFlags< ScaleComponent > ScaleComponents
Scale components.
Public Member Functions
QwtAbstractScaleDraw ()
Constructor.
virtual ~QwtAbstractScaleDraw ()
Destructor.
void setScaleDiv (const QwtScaleDiv &)
const QwtScaleDiv & scaleDiv () const
void setTransformation (QwtTransform *)
const QwtScaleMap & scaleMap () const
QwtScaleMap & scaleMap ()
void enableComponent (ScaleComponent, bool enable=true)
bool hasComponent (ScaleComponent) const
void setTickLength (QwtScaleDiv::TickType, double length)
double tickLength (QwtScaleDiv::TickType) const
double maxTickLength () const
void setSpacing (double)
Set the spacing between tick and labels.
double spacing () const
Get the spacing.
void setPenWidth (int width)
Specify the width of the scale pen.
int penWidth () const
virtual void draw (QPainter *, const QPalette &) const
Draw the scale.
virtual QwtText label (double) const
Convert a value into its representing label.
virtual double extent (const QFont &font) const =0
void setMinimumExtent (double)
Set a minimum for the extent.
double minimumExtent () const
Protected Member Functions
virtual void drawTick (QPainter *painter, double value, double 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
Convert a value into its representing label and cache it.
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 setScaleDiv(), the
scale can be drawn with the draw() member.
Member Enumeration Documentation
enum QwtAbstractScaleDraw::ScaleComponent
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
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, 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 QwtScaleDraw, and QwtRoundScaleDraw.
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 Length of the tick
See also:
drawBackbone(), drawLabel()
Implemented in QwtScaleDraw, and QwtRoundScaleDraw.
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 & font) const [pure virtual]
Calculate the extent
The extent is the distance from the baseline to the outermost pixel of the scale draw in
opposite to its orientation. It is at least minimumExtent() pixels.
Parameters:
font Font used for drawing the tick labels
Returns:
Number of pixels
See also:
setMinimumExtent(), minimumExtent()
Implemented in QwtScaleDraw, and QwtRoundScaleDraw.
bool QwtAbstractScaleDraw::hasComponent (ScaleComponent component) const
Check if a component is enabled
Parameters:
component Component type
Returns:
true, when component is enabled
See also:
enableComponent()
void QwtAbstractScaleDraw::invalidateCache () [protected]
Invalidate the cache used by 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().toString(value). This method is often overloaded by applications to have
individual labels.
Parameters:
value Value
Returns:
Label string.
Reimplemented in QwtDateScaleDraw, and QwtCompassScaleDraw.
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
Returns:
Minimum extent
See also:
extent(), setMinimumExtent()
int QwtAbstractScaleDraw::penWidth () const
Returns:
Scale pen width
See also:
setPenWidth()
const QwtScaleDiv & QwtAbstractScaleDraw::scaleDiv () const
Returns:
scale division
const QwtScaleMap & QwtAbstractScaleDraw::scaleMap () const
Returns:
Map how to translate between scale and pixel values
QwtScaleMap & QwtAbstractScaleDraw::scaleMap ()
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 components 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 & scaleDiv)
Change the scale division
Parameters:
scaleDiv 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 (QwtTransform * 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.
Returns:
Spacing
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
Returns:
Length of the ticks
See also:
setTickLength(), maxTickLength()
Author
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