A abstract base class for drawing scales. More...
#include <qwt_abstract_scale_draw.h>
Public Types | |
enum | ScaleComponent { Backbone = 1, Ticks = 2, Labels = 4 } |
Public Member Functions | |
QwtAbstractScaleDraw () | |
virtual | ~QwtAbstractScaleDraw () |
void | setScaleDiv (const QwtScaleDiv &s) |
const QwtScaleDiv & | scaleDiv () const |
void | setTransformation (QwtScaleTransformation *) |
const QwtScaleMap & | map () const |
void | enableComponent (ScaleComponent, bool enable=true) |
bool | hasComponent (ScaleComponent) const |
void | setTickLength (QwtScaleDiv::TickType, double length) |
double | tickLength (QwtScaleDiv::TickType) const |
double | majTickLength () 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 |
QwtScaleMap & | scaleMap () |
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 |
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.
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.
void QwtAbstractScaleDraw::draw | ( | QPainter * | painter, | |
const QPalette & | palette | |||
) | const [virtual] |
Draw the scale.
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
painter | Painter |
Implemented in QwtRoundScaleDraw, and QwtScaleDraw.
virtual void QwtAbstractScaleDraw::drawLabel | ( | QPainter * | painter, | |
double | value | |||
) | const [protected, pure virtual] |
Draws the label for a major scale tick
painter | Painter | |
value | Value |
Implemented in QwtRoundScaleDraw, and QwtScaleDraw.
virtual void QwtAbstractScaleDraw::drawTick | ( | QPainter * | painter, | |
double | value, | |||
double | len | |||
) | const [protected, pure virtual] |
Draw a tick
painter | Painter | |
value | Value of the tick | |
len | Lenght of the tick |
Implemented in QwtRoundScaleDraw, and QwtScaleDraw.
void QwtAbstractScaleDraw::enableComponent | ( | ScaleComponent | component, | |
bool | enable = true | |||
) |
En/Disable a component of the scale
component | Scale component | |
enable | On/Off |
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.
Implemented in QwtRoundScaleDraw, and QwtScaleDraw.
bool QwtAbstractScaleDraw::hasComponent | ( | ScaleComponent | component | ) | const |
Check if a component is enabled
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 | ( | double | value | ) | 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.
value | Value |
Reimplemented in QwtDialScaleDraw.
double QwtAbstractScaleDraw::majTickLength | ( | ) | const |
The same as QwtAbstractScaleDraw::tickLength(QwtScaleDiv::MajorTick).
const QwtScaleMap & QwtAbstractScaleDraw::map | ( | ) | const |
double QwtAbstractScaleDraw::minimumExtent | ( | ) | const |
Get the minimum extent
int QwtAbstractScaleDraw::penWidth | ( | ) | const |
const QwtScaleDiv & QwtAbstractScaleDraw::scaleDiv | ( | ) | const |
QwtScaleMap & QwtAbstractScaleDraw::scaleMap | ( | ) |
void QwtAbstractScaleDraw::setMinimumExtent | ( | double | minExtent | ) |
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.
minExtent | Minimum extent |
void QwtAbstractScaleDraw::setPenWidth | ( | int | width | ) |
void QwtAbstractScaleDraw::setScaleDiv | ( | const QwtScaleDiv & | sd | ) |
Change the scale division
sd | 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.
spacing | Spacing |
void QwtAbstractScaleDraw::setTickLength | ( | QwtScaleDiv::TickType | tickType, | |
double | length | |||
) |
Set the length of the ticks
tickType | Tick type | |
length | New length |
void QwtAbstractScaleDraw::setTransformation | ( | QwtScaleTransformation * | transformation | ) |
Change the transformation of the scale
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.
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.
font | Font | |
value | Value |
double QwtAbstractScaleDraw::tickLength | ( | QwtScaleDiv::TickType | tickType | ) | const |
Return the length of the ticks