QwtAbstractScaleDraw man page
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
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 &)
QwtAbstractScaleDraw (const QwtAbstractScaleDraw &)
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
virtual ~QwtAbstractScaleDraw ()
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
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, 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, intlen) 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 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()
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 (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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