QwtTextScaleDraw Class Reference

A scale draw that maps values to arbitrary text labels. More...

#include <qwt_text_scale_draw.h>

Inheritance diagram for QwtTextScaleDraw:

Classes
class	PrivateData

Public Member Functions
	QwtTextScaleDraw ()
	Constructor.
	QwtTextScaleDraw (const QMap< double, QString > &map)
void	setLabelMap (const QMap< double, QString > &map)
	Set the map that maps values to labels.
QMap< double, QString >	labelMap () const
	Get the map that maps values to labels.
virtual QwtText	label (double value) const override
	Map a value to a corresponding label.
Public Member Functions inherited from QwtScaleDraw
	QwtScaleDraw ()
	Constructor.
void	getBorderDistHint (const QFont &, int &start, int &end) const
	Get the border distance hint.
int	minLabelDist (const QFont &) const
	Get the minimum label distance.
int	minLength (const QFont &) const
	Get the minimum length.
virtual double	extent (const QFont &) const override
	Calculate the width/height that is needed for a vertical/horizontal scale.
void	move (double x, double y)
	Move the position of the scale.
void	move (const QPointF &)
	Move the position of the scale.
void	setLength (double length)
	Set the length of the backbone.
Alignment	alignment () const
	Return alignment of the scale.
void	setAlignment (Alignment)
	Set the alignment.
Qt::Orientation	orientation () const
	Return the orientation.
QPointF	pos () const
	Get origin of the scale.
double	length () const
	Get the length of the backbone.
void	setLabelAlignment (Qt::Alignment)
	Set the label alignment.
Qt::Alignment	labelAlignment () const
	Get the label flags.
void	setLabelRotation (double rotation)
	Set the label rotation.
double	labelRotation () const
	Get the label rotation.
int	maxLabelHeight (const QFont &) const
	Get the maximum label height.
int	maxLabelWidth (const QFont &) const
	Get the maximum label width.
QPointF	labelPosition (double value) const
	Get the label position for a value.
QRectF	labelRect (const QFont &, double value) const
	Get the label rectangle for a value.
QSizeF	labelSize (const QFont &, double value) const
	Get the label size for a value.
QRect	boundingLabelRect (const QFont &, double value) const
	Get the bounding label rectangle.
Public Member Functions inherited from QwtAbstractScaleDraw
	QwtAbstractScaleDraw ()
	Constructor for QwtAbstractScaleDraw.
void	setScaleDiv (const QwtScaleDiv &)
	Set the scale division.
const QwtScaleDiv &	scaleDiv () const
	Return the scale division.
void	setTransformation (QwtTransform *)
	Set the scale transformation.
const QwtScaleMap &	scaleMap () const
	Return the scale map (const version)
QwtScaleMap &	scaleMap ()
	Return the scale map (non-const version)
void	enableComponent (ScaleComponent, bool enable=true)
	Enable or disable a scale component.
bool	hasComponent (ScaleComponent) const
	Check if a component is enabled.
void	setTickLength (QwtScaleDiv::TickType, double length)
	Set the length of the ticks.
double	tickLength (QwtScaleDiv::TickType) const
	Get the length of the ticks.
double	maxTickLength () const
	Get the length of the longest tick.
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
	Get the scale pen width.
void	setSelected (bool on)
	Set whether the scale draw is selected.
bool	isSelected () const
	Check if the scale draw is selected.
void	setSelectedPenWidthOffset (qreal offset=1)
	Set the pen width offset for the axis when it is in selected state.
qreal	selectedPenWidthOffset () const
	Get the current pen width offset for the axis when it is in selected state.
virtual void	draw (QPainter *, const QPalette &) const
	Draw the scale.
void	setMinimumExtent (double)
	Set a minimum for the extent.
double	minimumExtent () const
	Get the minimum extent.
void	invalidateCache ()
	Invalidate the cache used by tickLabel()

Additional Inherited Members
Public Types inherited from QwtScaleDraw
enum	Alignment { BottomScale , TopScale , LeftScale , RightScale }
	Alignment of the scale draw. More...
Public Types inherited from QwtAbstractScaleDraw
enum	ScaleComponent { Backbone = 0x01 , Ticks = 0x02 , Labels = 0x04 }
	Components of a scale. More...
Protected Member Functions inherited from QwtScaleDraw
QTransform	labelTransformation (const QPointF &, const QSizeF &) const
	Calculate the transformation that is needed to paint a label.
virtual void	drawTick (QPainter *, double value, double len) const override
	Draw a tick.
virtual void	drawBackbone (QPainter *) const override
	Draws the baseline of the scale.
virtual void	drawLabel (QPainter *, double value) const override
	Draws the label for a major scale tick.
Protected Member Functions inherited from QwtAbstractScaleDraw
const QwtText &	tickLabel (const QFont &, double value) const
	Convert a value into its representing label and cache it.

Detailed Description

A scale draw that maps values to arbitrary text labels.

QwtTextScaleDraw displays user-defined text labels at specific numeric tick positions. It keeps a map from double values to strings and returns the matching string for each major tick value, so a linear axis can show category text (e.g. "Mon", "Tue", "Wed") instead of numbers.

The numeric tick positions are controlled by the scale engine and the QwtScaleDiv like a plain QwtScaleDraw. Only the label text is replaced through the value-to-string map. Values that do not match any key produce an empty label.

Usually the scale draw is combined with an explicit QwtScaleDiv whose major ticks match the map keys.

QMap< double, QString > labels;
labels.insert(0.0, "Mon");
labels.insert(1.0, "Tue");
labels.insert(2.0, "Wed");
plot->setAxisScaleDraw(QwtPlot::xBottom, new QwtTextScaleDraw(labels));

See also

QwtScaleDraw, QwtPlot::setAxisScaleDraw()

Constructor & Destructor Documentation

QwtTextScaleDraw()

QwtTextScaleDraw::QwtTextScaleDraw ( )

explicit

Constructor.

Constructs a text scale draw with an empty label map, so no labels are displayed until setLabelMap() is called.

Constructor

Parameters

[in]

map

Value to label map

Constructs a text scale draw with a custom value-to-label map. The values of the major ticks are looked up in this map to obtain the displayed text.

See also

setLabelMap(), labelMap()

Destructor

Member Function Documentation

label()

QwtText QwtTextScaleDraw::label ( double  value ) const

overridevirtual

Map a value to a corresponding label.

Parameters

[in]

value

Value that will be mapped

Returns

The label corresponding to value, or a null text if value matches no key

label() looks up the labelMap() for a corresponding label for value. Matching uses a small tolerance (1e-6) to be robust against floating point drift of the tick values. If no key matches, a null text is returned.

See also

labelMap(), setLabelMap()

Reimplemented from QwtAbstractScaleDraw.

labelMap()

QMap< double, QString > QwtTextScaleDraw::labelMap

(

)

const

Get the map that maps values to labels.

Returns

Map mapping values to labels

See also

setLabelMap()

setLabelMap()

void QwtTextScaleDraw::setLabelMap

(

const QMap< double, QString > &

map

)

Set the map that maps values to labels.

Parameters

[in]

map

Value to label map

The values of the major ticks are found by looking into this map. Values that do not match any key produce an empty label.

Warning

The map has no effect for values that are not major tick values. Major ticks are controlled by the scale engine and QwtScaleDiv.

See also

labelMap(), QwtScaleDraw::setScale()

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The documentation for this class was generated from the following files:

• /home/runner/work/QWT/QWT/src/plot/qwt_text_scale_draw.h
• /home/runner/work/QWT/QWT/src/plot/qwt_text_scale_draw.cpp