QGlyphRun Class Reference

The QGlyphRun class provides direct access to the internal glyphs in a font. More...

 #include <QGlyphRun>

This class was introduced in Qt 4.8.

List of all members, including inherited members

Public Functions

	QGlyphRun ()
	QGlyphRun ( const QGlyphRun & other )
	~QGlyphRun ()
void	clear ()
QVector<quint32>	glyphIndexes () const
bool	overline () const
QVector<QPointF>	positions () const
QRawFont	rawFont () const
void	setGlyphIndexes ( const QVector<quint32> & glyphIndexes )
void	setOverline ( bool overline )
void	setPositions ( const QVector<QPointF> & positions )
void	setRawData ( const quint32 * glyphIndexArray, const QPointF * glyphPositionArray, int size )
void	setRawFont ( const QRawFont & rawFont )
void	setStrikeOut ( bool strikeOut )
void	setUnderline ( bool underline )
bool	strikeOut () const
bool	underline () const
bool	operator!= ( const QGlyphRun & other ) const
QGlyphRun &	operator= ( const QGlyphRun & other )
bool	operator== ( const QGlyphRun & other ) const

Detailed Description

The QGlyphRun class provides direct access to the internal glyphs in a font.

When Qt displays a string of text encoded in Unicode, it will first convert the Unicode points into a list of glyph indexes and a list of positions based on one or more fonts. The Unicode representation of the text and the QFont object will in this case serve as a convenient abstraction that hides the details of what actually takes place when displaying the text on-screen. For instance, by the time the text actually reaches the screen, it may be represented by a set of fonts in addition to the one specified by the user, e.g. in case the originally selected font did not support all the writing systems contained in the text.

Under certain circumstances, it can be useful as an application developer to have more low-level control over which glyphs in a specific font are drawn to the screen. This could for instance be the case in applications that use an external font engine and text shaper together with Qt. QGlyphRun provides an interface to the raw data needed to get text on the screen. It contains a list of glyph indexes, a position for each glyph and a font.

It is the user's responsibility to ensure that the selected font actually contains the provided glyph indexes.

QTextLayout::glyphRuns() or QTextFragment::glyphRuns() can be used to convert unicode encoded text into a list of QGlyphRun objects, and QPainter::drawGlyphRun() can be used to draw the glyphs.

Note: Please note that QRawFont is considered local to the thread in which it is constructed. This in turn means that a new QRawFont will have to be created and set on the QGlyphRun if it is moved to a different thread. If the QGlyphRun contains a reference to a QRawFont from a different thread than the current, it will not be possible to draw the glyphs using a QPainter, as the QRawFont is considered invalid and inaccessible in this case.

Member Function Documentation

QGlyphRun::QGlyphRun ()

Constructs an empty QGlyphRun object.

QGlyphRun::QGlyphRun ( const QGlyphRun & other )

Constructs a QGlyphRun object which is a copy of other.

QGlyphRun::~QGlyphRun ()

Destroys the QGlyphRun.

void QGlyphRun::clear ()

Clears all data in the QGlyphRun object.

QVector<quint32> QGlyphRun::glyphIndexes () const

Returns the glyph indexes for this QGlyphRun object.

See also setGlyphIndexes() and setPositions().

bool QGlyphRun::overline () const

Returns true if this QGlyphRun should be painted with an overline decoration.

See also setOverline().

QVector<QPointF> QGlyphRun::positions () const

Returns the position of the edge of the baseline for each glyph in this set of glyph indexes.

See also setPositions().

QRawFont QGlyphRun::rawFont () const

Returns the font selected for this QGlyphRun object.

See also setRawFont().

void QGlyphRun::setGlyphIndexes ( const QVector<quint32> & glyphIndexes )

Set the glyph indexes for this QGlyphRun object to glyphIndexes. The glyph indexes must be valid for the selected font.

See also glyphIndexes().

void QGlyphRun::setOverline ( bool overline )

Indicates that this QGlyphRun should be painted with an overline decoration if overline is true. Otherwise the QGlyphRun should be painted with no overline decoration.

See also overline().

void QGlyphRun::setPositions ( const QVector<QPointF> & positions )

Sets the positions of the edge of the baseline for each glyph in this set of glyph indexes to positions.

See also positions().

void QGlyphRun::setRawData ( const quint32 * glyphIndexArray, const QPointF * glyphPositionArray, int size )

Sets the glyph indexes and positions of this QGlyphRun to use the first size elements in the arrays glyphIndexArray and glyphPositionArray. The data is not copied. The caller must guarantee that the arrays are not deleted as long as this QGlyphRun and any copies of it exists.

See also setGlyphIndexes() and setPositions().

void QGlyphRun::setRawFont ( const QRawFont & rawFont )

Sets the font specified by rawFont to be the font used to look up the glyph indexes.

See also rawFont() and setGlyphIndexes().

void QGlyphRun::setStrikeOut ( bool strikeOut )

Indicates that this QGlyphRun should be painted with an strike out decoration if strikeOut is true. Otherwise the QGlyphRun should be painted with no strike out decoration.

See also strikeOut().

void QGlyphRun::setUnderline ( bool underline )

Indicates that this QGlyphRun should be painted with an underline decoration if underline is true. Otherwise the QGlyphRun should be painted with no underline decoration.

See also underline().

bool QGlyphRun::strikeOut () const

Returns true if this QGlyphRun should be painted with a strike out decoration.

See also setStrikeOut().

bool QGlyphRun::underline () const

Returns true if this QGlyphRun should be painted with an underline decoration.

See also setUnderline().

bool QGlyphRun::operator!= ( const QGlyphRun & other ) const

Compares other to this QGlyphRun object. Returns true if any of the list of glyph indexes, the list of positions or the font are different, otherwise returns false.

QGlyphRun & QGlyphRun::operator= ( const QGlyphRun & other )

Assigns other to this QGlyphRun object.

bool QGlyphRun::operator== ( const QGlyphRun & other ) const

Compares other to this QGlyphRun object. Returns true if the list of glyph indexes, the list of positions and the font are all equal, otherwise returns false.

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