QwtAbstractScaleDraw(3) | Qwt User's Guide | QwtAbstractScaleDraw(3) |
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 ()
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 setPenWidthF (qreal width)
Specify the width of the scale pen. qreal penWidthF () 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
void invalidateCache ()
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
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.
Definition at line 31 of file qwt_abstract_scale_draw.h.
Member Typedef Documentation
typedef QFlags<ScaleComponent > QwtAbstractScaleDraw::ScaleComponents
An ORed combination of ScaleComponent values.
Definition at line 51 of file qwt_abstract_scale_draw.h.
Member Enumeration Documentation
enum QwtAbstractScaleDraw::ScaleComponent
Components of a scale
See also
Enumerator
Definition at line 39 of file qwt_abstract_scale_draw.h.
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
Definition at line 60 of file qwt_abstract_scale_draw.cpp.
Member Function Documentation
void QwtAbstractScaleDraw::draw (QPainter * painter, const QPalette & palette) const [virtual]
Draw the scale.
Parameters
palette Palette, text color is used for the labels, foreground color for ticks and backbone
Definition at line 169 of file qwt_abstract_scale_draw.cpp.
virtual void QwtAbstractScaleDraw::drawBackbone (QPainter * painter) const [protected], [pure virtual]
Draws the baseline of the scale
Parameters
See also
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
value Value
See also
Implemented in QwtScaleDraw, and QwtRoundScaleDraw.
virtual void QwtAbstractScaleDraw::drawTick (QPainter * painter, double value, double len) const [protected], [pure virtual]
Draw a tick
Parameters
value Value of the tick
len Length of the tick
See also
Implemented in QwtScaleDraw, and QwtRoundScaleDraw.
void QwtAbstractScaleDraw::enableComponent (ScaleComponent component, bool enable = true)
En/Disable a component of the scale
Parameters
enable On/Off
See also
Definition at line 79 of file qwt_abstract_scale_draw.cpp.
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
Returns
See also
Implemented in QwtScaleDraw, and QwtRoundScaleDraw.
bool QwtAbstractScaleDraw::hasComponent (ScaleComponent component) const
Check if a component is enabled
Parameters
Returns
See also
Definition at line 95 of file qwt_abstract_scale_draw.cpp.
void QwtAbstractScaleDraw::invalidateCache ()
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.
Definition at line 417 of file qwt_abstract_scale_draw.cpp.
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
Returns
Reimplemented in QwtDateScaleDraw, and QwtCompassScaleDraw.
Definition at line 375 of file qwt_abstract_scale_draw.cpp.
double QwtAbstractScaleDraw::maxTickLength () const
Returns
Useful for layout calculations
See also
Definition at line 355 of file qwt_abstract_scale_draw.cpp.
double QwtAbstractScaleDraw::minimumExtent () const
Get the minimum extent
Returns
See also
Definition at line 302 of file qwt_abstract_scale_draw.cpp.
qreal QwtAbstractScaleDraw::penWidthF () const
Returns
See also
Definition at line 156 of file qwt_abstract_scale_draw.cpp.
const QwtScaleDiv & QwtAbstractScaleDraw::scaleDiv () const
Returns
Definition at line 133 of file qwt_abstract_scale_draw.cpp.
QwtScaleMap & QwtAbstractScaleDraw::scaleMap ()
Returns
Definition at line 127 of file qwt_abstract_scale_draw.cpp.
const QwtScaleMap & QwtAbstractScaleDraw::scaleMap () const
Returns
Definition at line 121 of file qwt_abstract_scale_draw.cpp.
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
See also
Definition at line 289 of file qwt_abstract_scale_draw.cpp.
void QwtAbstractScaleDraw::setPenWidthF (qreal width)
Specify the width of the scale pen.
Parameters
See also
Definition at line 144 of file qwt_abstract_scale_draw.cpp.
void QwtAbstractScaleDraw::setScaleDiv (const QwtScaleDiv & scaleDiv)
Change the scale division
Parameters
Definition at line 104 of file qwt_abstract_scale_draw.cpp.
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
See also
Definition at line 254 of file qwt_abstract_scale_draw.cpp.
void QwtAbstractScaleDraw::setTickLength (QwtScaleDiv::TickType tickType, double length)
Set the length of the ticks
Parameters
length New length
Warning
Definition at line 315 of file qwt_abstract_scale_draw.cpp.
void QwtAbstractScaleDraw::setTransformation (QwtTransform * transformation)
Change the transformation of the scale
Parameters
Definition at line 115 of file qwt_abstract_scale_draw.cpp.
double QwtAbstractScaleDraw::spacing () const
Get the spacing. The spacing is the distance between ticks and labels. The default spacing is 4 pixels.
Returns
See also
Definition at line 271 of file qwt_abstract_scale_draw.cpp.
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
value Value
Returns
Definition at line 393 of file qwt_abstract_scale_draw.cpp.
double QwtAbstractScaleDraw::tickLength (QwtScaleDiv::TickType tickType) const
Returns
See also
Definition at line 338 of file qwt_abstract_scale_draw.cpp.
Author
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Sun Jul 18 2021 | Version 6.2.0 |