Qwt User's Guide
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A plot item, which displays a text label. More...
#include <qwt_plot_textlabel.h>
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. |
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.
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 );
Constructor.
Initializes an text label with an empty text
Sets the following item attributes:
The z value is initialized by 150
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 |
Implements QwtPlotItem.
int QwtPlotTextLabel::margin | ( | ) | const |
int QwtPlotTextLabel::rtti | ( | ) | const [virtual] |
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.
margin | Margin |
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 |
QwtText QwtPlotTextLabel::text | ( | ) | const |
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 |