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 |
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| 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()
◆ draw()
| virtual void QwtTextEngine::draw |
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QPainter * |
painter, |
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const QRectF & |
rect, |
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int |
flags, |
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const QString & |
text |
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| const |
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pure virtual |
◆ heightForWidth()
| virtual double QwtTextEngine::heightForWidth |
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const QFont & |
font, |
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int |
flags, |
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const QString & |
text, |
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double |
width |
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| const |
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pure virtual |
◆ mightRender()
| virtual bool QwtTextEngine::mightRender |
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const QString & |
text | ) |
const |
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pure virtual |
◆ textMargins()
| virtual void QwtTextEngine::textMargins |
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const QFont & |
font, |
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const QString & |
text, |
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double & |
left, |
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double & |
right, |
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double & |
top, |
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double & |
bottom |
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| const |
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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 QwtMathMLTextEngine, QwtRichTextEngine, and QwtPlainTextEngine.
◆ textSize()
| virtual QSizeF QwtTextEngine::textSize |
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const QFont & |
font, |
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int |
flags, |
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const QString & |
text |
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| const |
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pure virtual |