QwtPlotTextLabel - Man Page

A plot item, which displays a text label.

Synopsis

#include <qwt_plot_textlabel.h>

Inherits QwtPlotItem.

Public Member Functions

QwtPlotTextLabel ()
Constructor.
virtual ~QwtPlotTextLabel ()
Destructor.
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.

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 );

\endpar

See also

QwtPlotMarker

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

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.

int QwtPlotTextLabel::margin () const

Returns

Margin added to the contentsMargins() of the canvas

See also

setMargin()

int QwtPlotTextLabel::rtti () const [virtual]

Returns

QwtPlotItem::Rtti_PlotTextLabel

Reimplemented from QwtPlotItem.

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()

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()

QwtText QwtPlotTextLabel::text () const

Returns

Text to be displayed

See also

setText()

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()

Author

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

Info

Mon Jun 1 2020 Version 6.1.5 Qwt User's Guide