CopperSpice API  1.7.2
QGlyphRun Class Reference

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

Public Typedefs

using GlyphRunFlags = QFlags< GlyphRunFlag >

Public Types

enum  GlyphRunFlag

Public Methods

 QGlyphRun ()
 QGlyphRun (const QGlyphRun &other)
 ~QGlyphRun ()
QRectF boundingRect () const
void clear ()
GlyphRunFlags flags () const
QVector< quint32glyphIndexes () const
bool isEmpty () const
bool isRightToLeft () const
bool operator!= (const QGlyphRun &other) const
QGlyphRun & operator= (const QGlyphRun &other)
QGlyphRun & operator= (QGlyphRun &&other)
bool operator== (const QGlyphRun &other) const
bool overline () const
QVector< QPointFpositions () const
QRawFont rawFont () const
void setBoundingRect (const QRectF &boundingRect)
void setFlag (GlyphRunFlag flag, bool enabled=true)
void setFlags (GlyphRunFlags flags)
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 setRightToLeft (bool on)
void setStrikeOut (bool strikeOut)
void setUnderline (bool underline)
bool strikeOut () const
void swap (QGlyphRun &other)
bool underline () const


class QTextLine

Detailed Description

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

When CopperSpice 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 to have low-level control over which glyphs in a specific font are drawn. This can occur in applications which use an external font engine and text shaper together with CopperSpice. 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 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.

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.
See also
setGlyphIndexes(), setPositions()

Member Typedef Documentation

Typedef for QFlags<GlyphRunFlag>. Refer to QGlyphRun::GlyphRunFlag for documentation.

Member Enumeration Documentation

This enum describes flags that alter the way the run of glyphs might be presented or behave in a visual layout. The layout which generates the glyph runs can set these flags based on relevant internal data, to retain information needed to present the text as intended by the user of the layout.

QGlyphRun::Overline 0x01 glyphs should be visualized together with an overline
QGlyphRun::Underline 0x02 glyphs should be visualized together with an underline
QGlyphRun::StrikeOut 0x04 glyphs should be struck out visually
QGlyphRun::RightToLeft 0x08 glyphs are ordered right to left, this can affect the positioning of other screen elements that are relative to the glyph run, such as an inline text object
QGlyphRun::SplitLigature 0x10 Indicates that the glyph run splits a ligature glyph. This means that a ligature glyph is included in the run, but the characters represented by it corresponds only to part of that ligature. The glyph run's boundingRect() function can in this case be used to retrieve the area covered by glyphs that correspond to the characters represented by the glyph run. When visualizing the glyphs, care needs to be taken to clip to this bounding rect to ensure that only the corresponding part of the ligature is painted. In particular, this can be the case when retrieving a glyph run from a QTextLayout for a specific character range, e.g. when retrieving the selected area of a QTextLayout.

Constructor & Destructor 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.

Method Documentation

QRectF QGlyphRun::boundingRect ( ) const

Returns the smallest rectangle that contains all glyphs in this QGlyphRun. If a bounding rect has been set using setBoundingRect(), then this will be returned. Otherwise the bounding rect will be calculated based on the font metrics of the glyphs in the glyph run.

See also
void QGlyphRun::clear ( )

Clears all data in the QGlyphRun object.

GlyphRunFlags QGlyphRun::flags ( ) const

Returns the flags set for this QGlyphRun.

See also
setFlags(), setFlag(), setFlag()
QVector< quint32 > QGlyphRun::glyphIndexes ( ) const

Returns the glyph indexes for this QGlyphRun object.

See also
setGlyphIndexes(), setPositions()
bool QGlyphRun::isEmpty ( ) const

Returns true if the QGlyphRun does not contain any glyphs.

bool QGlyphRun::isRightToLeft ( ) const

Returns true if this QGlyphRun contains glyphs that are painted from the right to the left.

See also
setRightToLeft(), flags()
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.

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

Move 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.

bool QGlyphRun::overline ( ) const

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

See also
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
QRawFont QGlyphRun::rawFont ( ) const

Returns the font selected for this QGlyphRun object.

See also
void QGlyphRun::setBoundingRect ( const QRectF boundingRect)

Sets the bounding rect of the glyphs in this QGlyphRun to be boundingRect. This rectangle will be returned by boundingRect() unless it is empty, in which case the bounding rectangle of the glyphs in the glyph run will be returned instead.

Note: Unless you are implementing text shaping, you should not have to use this function. It is used specifically when the QGlyphRun should represent an area which is smaller than the area of the glyphs it contains. This could happen e.g. if the glyph run is retrieved by calling QTextLayout::glyphRuns() and the specified range only includes part of a ligature (where two or more characters are combined to a single glyph.) When this is the case, the bounding rect should only include the appropriate part of the ligature glyph, based on a calculation of the average width of the characters in the ligature.

In order to support such a case (an example is selections which should be drawn with a different color than the main text color), it is necessary to clip the painting mechanism to the rectangle returned from boundingRect() to avoid drawing the entire ligature glyph.

See also
void QGlyphRun::setFlag ( QGlyphRun::GlyphRunFlag  flag,
bool  enabled = true 

If enabled is true, then flag is enabled, otherwise, it is disabled.

See also
flags(), setFlags()
void QGlyphRun::setFlags ( QGlyphRun::GlyphRunFlags  flags)

Sets the flags of this QGlyphRun to flags.

See also
setFlag(), flags()
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
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
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
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(), 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(), setGlyphIndexes()
void QGlyphRun::setRightToLeft ( bool  rightToLeft)

Indicates that this QGlyphRun contains glyphs that should be ordered from the right to left if rightToLeft is true. Otherwise the order of the glyphs is assumed to be left to right.

See also
isRightToLeft(), setFlag(), setFlags()
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
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
bool QGlyphRun::strikeOut ( ) const

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

See also
void QGlyphRun::swap ( QGlyphRun &  other)

Swaps this glyph run instance with other. This function is very fast and never fails.

bool QGlyphRun::underline ( ) const

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

See also