QwtTextEngine Class Reference

Abstract base class for rendering text strings. More...

#include <qwt_text_engine.h>

Inheritance diagram for QwtTextEngine:

Public Member Functions
virtual	~QwtTextEngine ()
	Destructor.
virtual double	heightForWidth (const QFont &font, int flags, const QString &text, double width) const =0
virtual QSizeF	textSize (const QFont &font, int flags, const QString &text) const =0
virtual bool	mightRender (const QString &text) const =0
virtual void	textMargins (const QFont &font, const QString &text, double &left, double &right, double &top, double &bottom) const =0
virtual void	draw (QPainter *painter, const QRectF &rect, int flags, const QString &text) const =0

Protected Member Functions
	QwtTextEngine ()
	Constructor.

Detailed Description

Abstract base class for rendering text strings.

A text engine is responsible for rendering texts for a specific text format. They are used by QwtText to render a text.

QwtPlainTextEngine and QwtRichTextEngine are part of the Qwt library. The implementation of QwtMathMLTextEngine uses code from the Qt solution package. Because of license implications it is built into a separate library.

See also

QwtText::setTextEngine()

Member Function Documentation

draw()

virtual void QwtTextEngine::draw ( QPainter *  painter, const QRectF &  rect, int  flags, const QString &  text  ) const

pure virtual

Draw the text in a clipping rectangle

Parameters

painter	Painter
rect	Clipping rectangle
flags	Bitwise OR of the flags like in for QPainter::drawText()
text	Text to be rendered

Implemented in QwtMathMLTextEngine, QwtRichTextEngine, and QwtPlainTextEngine.

heightForWidth()

virtual double QwtTextEngine::heightForWidth ( const QFont &  font, int  flags, const QString &  text, double  width  ) const

pure virtual

Find the height for a given width

Parameters

font	Font of the text
flags	Bitwise OR of the flags used like in QPainter::drawText
text	Text to be rendered
width	Width

Returns

Calculated height

Implemented in QwtMathMLTextEngine, QwtRichTextEngine, and QwtPlainTextEngine.

mightRender()

virtual bool QwtTextEngine::mightRender ( const QString &  text ) const

pure virtual

Test if a string can be rendered by this text engine

Parameters

text	Text to be tested

Returns

true, if it can be rendered

Implemented in QwtMathMLTextEngine, QwtRichTextEngine, and QwtPlainTextEngine.

textMargins()

virtual void QwtTextEngine::textMargins ( const QFont &  font, const QString &  text, double &  left, double &  right, double &  top, double &  bottom  ) const

pure virtual

Return margins around the texts

The textSize might include margins around the text, like QFontMetrics::descent(). In situations where texts need to be aligned in detail, knowing these margins might improve the layout calculations.

Parameters

font	Font of the text
text	Text to be rendered
left	Return value for the left margin
right	Return value for the right margin
top	Return value for the top margin
bottom	Return value for the bottom margin

Implemented in QwtMathMLTextEngine, QwtRichTextEngine, and QwtPlainTextEngine.

textSize()

virtual QSizeF QwtTextEngine::textSize ( const QFont &  font, int  flags, const QString &  text  ) const

pure virtual

Returns the size, that is needed to render text

Parameters

font	Font of the text
flags	Bitwise OR of the flags like in for QPainter::drawText
text	Text to be rendered

Returns

Calculated size

Implemented in QwtMathMLTextEngine, QwtRichTextEngine, and QwtPlainTextEngine.