QwtPlotTextLabel Class Reference

A plot item, which displays a text label. More...

#include <qwt_plot_textlabel.h>

Inheritance diagram for QwtPlotTextLabel:

Classes
class	PrivateData

Public Member Functions
	QwtPlotTextLabel ()
	Constructor.
virtual	~QwtPlotTextLabel ()
	Destructor.
virtual int	rtti () const QWT_OVERRIDE
void	setText (const QwtText &)
	Set the text.
QwtText	text () const
void	setMargin (int margin)
	Set the margin.
int	margin () const
virtual QRectF	textRect (const QRectF &, const QSizeF &) const
	Align the text label.
Public Member Functions inherited from QwtPlotItem
	QwtPlotItem ()
	Constructor.
	QwtPlotItem (const QString &title)
	Constructor.
	QwtPlotItem (const QwtText &title)
	Constructor.
virtual	~QwtPlotItem ()
	Destroy the QwtPlotItem.
void	attach (QwtPlot *plot)
	Attach the item to a plot.
void	detach ()
	This method detaches a QwtPlotItem from any QwtPlot it has been associated with.
QwtPlot *	plot () const
	Return attached plot.
void	setTitle (const QString &title)
	Set a new title.
void	setTitle (const QwtText &title)
	Set a new title.
const QwtText &	title () const
void	setItemAttribute (ItemAttribute, bool on=true)
	Toggle an item attribute.
bool	testItemAttribute (ItemAttribute) const
	Test an item attribute.
void	setItemInterest (ItemInterest, bool on=true)
	Toggle an item interest.
bool	testItemInterest (ItemInterest) const
	Test an item interest.
void	setRenderHint (RenderHint, bool on=true)
	Toggle an render hint.
bool	testRenderHint (RenderHint) const
	Test a render hint.
void	setRenderThreadCount (uint numThreads)
	On multi core systems rendering of certain plot item ( f.e QwtPlotRasterItem ) can be done in parallel in several threads.
uint	renderThreadCount () const
void	setLegendIconSize (const QSize &)
	Set the size of the legend icon.
QSize	legendIconSize () const
double	z () const
	Plot items are painted in increasing z-order.
void	setZ (double z)
	Set the z value.
void	show ()
	Show the item.
void	hide ()
	Hide the item.
virtual void	setVisible (bool)
	Show/Hide the item.
bool	isVisible () const
void	setAxes (QwtAxisId xAxis, QwtAxisId yAxis)
	Set X and Y axis.
void	setXAxis (QwtAxisId)
	Set the X axis.
QwtAxisId	xAxis () const
	Return xAxis.
void	setYAxis (QwtAxisId)
	Set the Y axis.
QwtAxisId	yAxis () const
	Return yAxis.
virtual void	itemChanged ()
	Update the legend and call QwtPlot::autoRefresh() for the parent plot.
virtual void	legendChanged ()
	Update the legend of the parent plot.
virtual QRectF	boundingRect () const
virtual void	getCanvasMarginHint (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect, double &left, double &top, double &right, double &bottom) const
	Calculate a hint for the canvas margin.
virtual void	updateScaleDiv (const QwtScaleDiv &, const QwtScaleDiv &)
	Update the item to changes of the axes scale division.
virtual void	updateLegend (const QwtPlotItem *, const QList< QwtLegendData > &)
	Update the item to changes of the legend info.
QRectF	scaleRect (const QwtScaleMap &, const QwtScaleMap &) const
	Calculate the bounding scale rectangle of 2 maps.
QRectF	paintRect (const QwtScaleMap &, const QwtScaleMap &) const
	Calculate the bounding paint rectangle of 2 maps.
virtual QList< QwtLegendData >	legendData () const
	Return all information, that is needed to represent the item on the legend.
virtual QwtGraphic	legendIcon (int index, const QSizeF &) const

Protected Member Functions
virtual void	draw (QPainter *, const QwtScaleMap &, const QwtScaleMap &, const QRectF &) const QWT_OVERRIDE
	Draw the text label.
void	invalidateCache ()
	Invalidate all internal cache.
Protected Member Functions inherited from QwtPlotItem
QwtGraphic	defaultIcon (const QBrush &, const QSizeF &) const
	Return a default icon from a brush.

Additional Inherited Members
Public Types inherited from QwtPlotItem
enum	RttiValues {   Rtti_PlotItem = 0 , Rtti_PlotGrid , Rtti_PlotScale , Rtti_PlotLegend ,   Rtti_PlotMarker , Rtti_PlotCurve , Rtti_PlotSpectroCurve , Rtti_PlotIntervalCurve ,   Rtti_PlotHistogram , Rtti_PlotSpectrogram , Rtti_PlotGraphic , Rtti_PlotTradingCurve ,   Rtti_PlotBarChart , Rtti_PlotMultiBarChart , Rtti_PlotShape , Rtti_PlotTextLabel ,   Rtti_PlotZone , Rtti_PlotVectorField , Rtti_PlotUserItem = 1000 }
	Runtime type information. More...
enum	ItemAttribute { Legend = 0x01 , AutoScale = 0x02 , Margins = 0x04 }
	Plot Item Attributes. More...
enum	ItemInterest { ScaleInterest = 0x01 , LegendInterest = 0x02 }
	Plot Item Interests/绘图项关注的事件类型 More...
enum	RenderHint { RenderAntialiased = 0x1 }
	Render hints. More...

Detailed Description

A plot item, which displays a text label.

QwtPlotTextLabel displays a text label aligned to the plot canvas.

In opposite to QwtPlotMarker the position of the label is unrelated to plot coordinates.

As drawing a text is an expensive operation the label is cached in a pixmap to speed up replots.

Example

The following code shows how to add a title.

QwtText title( "Plot Title" );
title.setRenderFlags( Qt::AlignHCenter | Qt::AlignTop );
 
QFont font;
font.setBold( true );
title.setFont( font );
 
QwtPlotTextLabel *titleItem = new QwtPlotTextLabel();
titleItem->setText( title );
titleItem->attach( plot );

See also

QwtPlotMarker

Constructor & Destructor Documentation

QwtPlotTextLabel()

QwtPlotTextLabel::QwtPlotTextLabel

(

)

Constructor.

Initializes an text label with an empty text

Sets the following item attributes:

• QwtPlotItem::AutoScale: true
• QwtPlotItem::Legend: false

The z value is initialized by 150

See also

QwtPlotItem::setItemAttribute(), QwtPlotItem::setZ()

Member Function Documentation

draw()

void QwtPlotTextLabel::draw ( QPainter *  painter, const QwtScaleMap &  xMap, const QwtScaleMap &  yMap, const QRectF &  canvasRect  ) const

protectedvirtual

Draw the text label.

Parameters

painter	Painter
xMap	x Scale Map
yMap	y Scale Map
canvasRect	Contents rectangle of the canvas in painter coordinates

See also

textRect()

Implements QwtPlotItem.

margin()

int QwtPlotTextLabel::margin

(

)

const

Returns

Margin added to the contentsMargins() of the canvas

See also

setMargin()

rtti()

int QwtPlotTextLabel::rtti ( ) const

virtual

Returns

QwtPlotItem::Rtti_PlotTextLabel

Reimplemented from QwtPlotItem.

setMargin()

void QwtPlotTextLabel::setMargin

(

int

margin

)

Set the margin.

The margin is the distance between the contentsRect() of the plot canvas and the rectangle where the label can be displayed.

Parameters

margin

Margin

See also

margin(), textRect()

setText()

void QwtPlotTextLabel::setText

(

const QwtText &

text

)

Set the text.

The label will be aligned to the plot canvas according to the alignment flags of text.

Parameters

text	Text to be displayed

See also

text(), QwtText::renderFlags()

text()

QwtText QwtPlotTextLabel::text

(

)

const

Returns

Text to be displayed

See also

setText()

textRect()

QRectF QwtPlotTextLabel::textRect ( const QRectF &  rect, const QSizeF &  textSize  ) const

virtual

Align the text label.

Parameters

rect	Canvas rectangle with margins subtracted
textSize	Size required to draw the text

Returns

A rectangle aligned according the the alignment flags of the text.

See also

setMargin(), QwtText::renderFlags(), QwtText::textSize()

---

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

• /home/runner/work/QWT/QWT/src/qwt_plot_textlabel.h
• /home/runner/work/QWT/QWT/src/qwt_plot_textlabel.cpp