QwtPlotTextLabel(3)

NAME
QwtPlotTextLabel - 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( this );

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

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