QwtTextEngine Class Reference

#include <qwt_text_engine.h>

Inherited by QwtMathMLTextEngine, QwtPlainTextEngine, and QwtRichTextEngine.

List of all members.

Public Member Functions
virtual void	draw (QPainter *painter, const QRectF &rect, int flags, const QString &text) const =0
virtual double	heightForWidth (const QFont &font, int flags, const QString &text, double width) 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 QSizeF	textSize (const QFont &font, int flags, const QString &text) const =0
virtual	~QwtTextEngine ()
Protected Member Functions
	QwtTextEngine ()

---

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()

---

Constructor & Destructor Documentation

QwtTextEngine::~QwtTextEngine

(

)

[virtual]

Destructor.

QwtTextEngine::QwtTextEngine

(

)

[protected]

Constructor.

---

Member Function Documentation

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 QwtRichTextEngine, QwtPlainTextEngine, and QwtMathMLTextEngine.

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 QwtRichTextEngine, QwtPlainTextEngine, and QwtMathMLTextEngine.

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 QwtRichTextEngine, QwtPlainTextEngine, and QwtMathMLTextEngine.

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 aligend 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 QwtRichTextEngine, QwtPlainTextEngine, and QwtMathMLTextEngine.

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:

Caluclated size

Implemented in QwtRichTextEngine, QwtPlainTextEngine, and QwtMathMLTextEngine.