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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