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QwtTextEngine(3) Qwt User's Guide QwtTextEngine(3)

NAME

QwtTextEngine -
Abstract base class for rendering text strings.
 

SYNOPSIS

#include <qwt_text_engine.h>
Inherited by QwtMathMLTextEngine, QwtPlainTextEngine, and QwtRichTextEngine.

Public Member Functions


virtual ~QwtTextEngine ()
 
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 ()
 

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, intflags, 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 QwtPlainTextEngine, QwtRichTextEngine, and QwtMathMLTextEngine.

virtual double QwtTextEngine::heightForWidth (const QFont &font, intflags, const QString &text, doublewidth) 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 QwtPlainTextEngine, QwtRichTextEngine, 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 QwtPlainTextEngine, QwtRichTextEngine, 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 QwtPlainTextEngine, QwtRichTextEngine, and QwtMathMLTextEngine.

virtual QSizeF QwtTextEngine::textSize (const QFont &font, intflags, 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 QwtPlainTextEngine, QwtRichTextEngine, and QwtMathMLTextEngine.
 

Author

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Fri Apr 15 2011 Version 6.0.0