trusty (3) QwtAbstractScaleDraw.3.gz
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
Public Member Functions
QwtAbstractScaleDraw ()
virtual ~QwtAbstractScaleDraw ()
void setScaleDiv (const QwtScaleDiv &s)
const QwtScaleDiv & scaleDiv () const
void setTransformation (QwtScaleTransformation *)
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 margin)
double spacing () const
void setPenWidth (int width)
int penWidth () const
virtual void draw (QPainter *, const QPalette &) const
virtual QwtText label (double) const
virtual double extent (const QFont &) const =0
void setMinimumExtent (double)
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
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
typedef QFlags<ScaleComponent> QwtAbstractScaleDraw::ScaleComponents
Scale components.
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
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, doublevalue) 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, doublevalue, doublelen) 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 (ScaleComponentcomponent, boolenable = 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 (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, 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.
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
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 (doubleminExtent)
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 (intwidth)
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 (doublespacing)
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, doublelength) 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, 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
double QwtAbstractScaleDraw::tickLength (QwtScaleDiv::TickTypetickType) const Return the length of the ticks
See also:
setTickLength(), maxTickLength()
Author
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