Abstract base class for rendering text strings.  
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#include <qwt_text_engine.h>
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| virtual | ~QwtTextEngine () | 
|  | Destructor. 
 | 
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| virtual double | heightForWidth (const QFont &font, int flags, const QString &text, double width) const  =0 | 
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| virtual QSizeF | textSize (const QFont &font, int flags, const QString &text) const  =0 | 
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| virtual bool | mightRender (const QString &text) const  =0 | 
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| 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 | 
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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() 
  
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          | virtual void QwtTextEngine::draw | ( | QPainter * | painter, |  
          |  |  | const QRectF & | rect, |  
          |  |  | int | flags, |  
          |  |  | const QString & | text |  
          |  | ) |  | const |  | pure virtual | 
 
 
  
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          | virtual double QwtTextEngine::heightForWidth | ( | const QFont & | font, |  
          |  |  | int | flags, |  
          |  |  | const QString & | text, |  
          |  |  | double | width |  
          |  | ) |  | const |  | pure virtual | 
 
 
  
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          | virtual bool QwtTextEngine::mightRender | ( | const QString & | text | ) | const |  | pure virtual | 
 
 
  
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          | 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
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    | 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.
 
 
  
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          | virtual QSizeF QwtTextEngine::textSize | ( | const QFont & | font, |  
          |  |  | int | flags, |  
          |  |  | const QString & | text |  
          |  | ) |  | const |  | pure virtual |