QwtPlotTextLabel man page

QwtPlotTextLabel —

A plot item, which displays a text label.


#include <qwt_plot_textlabel.h>

Inherits QwtPlotItem.

Public Member Functions

QwtPlotTextLabel ()
virtual ~QwtPlotTextLabel ()
virtual int rtti () const

void setText (const QwtText &)

QwtText text () const

void setMargin (int margin)

int margin () const

virtual QRectF textRect (const QRectF &, const QSizeF &) const
Align the text label.

Protected Member Functions

virtual void draw (QPainter *, const QwtScaleMap &, const QwtScaleMap &, const QRectF &) const

void invalidateCache ()
Invalidate all internal cache.

Additional Inherited Members

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.


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( this );

See Also:


Constructor & Destructor Documentation

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

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

Draw the text label


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

See Also:


Implements QwtPlotItem.

int QwtPlotTextLabel::margin () const


Margin added to the contentsMargins() of the canvas

See Also:


int QwtPlotTextLabel::rtti () const [virtual]



Reimplemented from QwtPlotItem.

void QwtPlotTextLabel::setMargin (intmargin)

Set the margin

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


margin Margin

See Also:

margin(), textRect()

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.


text Text to be displayed

See Also:

text(), QwtText::renderFlags()

QwtText QwtPlotTextLabel::text () const


Text to be displayed

See Also:


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

Align the text label.


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


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

See Also:

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


Generated automatically by Doxygen for Qwt User's Guide from the source code.


Thu Dec 11 2014 Version 6.1.2 Qwt User's Guide