QtGui.QRawFont Class Reference

The QRawFont class provides access to a single physical instance of a font. More...

Inheritance diagram for QtGui.QRawFont:

Collaboration diagram for QtGui.QRawFont:

Public Types
enum	AntialiasingType { PixelAntialiasing = 0, SubPixelAntialiasing = 1 }
	More...

Public Member Functions
override bool	Equals (object o)
override int	GetHashCode ()
	QRawFont ()
	QRawFont (QRawFont other)
	QRawFont (QByteArray fontData, double pixelSize, QFont.HintingPreference hintingPreference=QFont.HintingPreference.PreferDefaultHinting)
	QRawFont (string fileName, double pixelSize, QFont.HintingPreference hintingPreference=QFont.HintingPreference.PreferDefaultHinting)
virtual void	CreateProxy ()
new bool	AdvancesForGlyphIndexes (ref uint glyphIndexes, QPointF advances, int numGlyphs)
new System.Collections.Generic.List < QPointF >	AdvancesForGlyphIndexes (System.Collections.Generic.List< System.UInt32 > glyphIndexes)
new QImage	AlphaMapForGlyph (uint glyphIndex, QRawFont.AntialiasingType antialiasingType=QRawFont.AntialiasingType.SubPixelAntialiasing)
new QImage	AlphaMapForGlyph (uint glyphIndex, QRawFont.AntialiasingType antialiasingType, QTransform transform)
new double	Ascent ()
new double	AverageCharWidth ()
new double	Descent ()
new string	FamilyName ()
new QByteArray	FontTable (string tagName)
new bool	GlyphIndexesForChars (QChar chars, int numChars, ref uint glyphIndexes, ref int numGlyphs)
new System.Collections.Generic.List < System.UInt32 >	GlyphIndexesForString (string text)
new QFont.HintingPreference	HintingPreference ()
new bool	IsValid ()
new double	Leading ()
new void	LoadFromData (QByteArray fontData, double pixelSize, QFont.HintingPreference hintingPreference)
new void	LoadFromFile (string fileName, double pixelSize, QFont.HintingPreference hintingPreference)
new double	MaxCharWidth ()
new QPainterPath	PathForGlyph (uint glyphIndex)
new QFont.Style	Style ()
new string	StyleName ()
new System.Collections.Generic.List < QFontDatabase.WritingSystem >	SupportedWritingSystems ()
new bool	SupportsCharacter (QChar character)
new bool	SupportsCharacter (uint ucs4)
new double	UnitsPerEm ()
new int	Weight ()
new double	xHeight ()
new void	Dispose ()

Static Public Member Functions
static QRawFont	FromFont (QFont font, QFontDatabase.WritingSystem writingSystem=QFontDatabase.WritingSystem.Any)
static bool	operator!= (QRawFont arg1, QRawFont arg2)
static bool	operator== (QRawFont arg1, QRawFont arg2)

Protected Member Functions
	QRawFont (System.Type dummy)

Protected Attributes
SmokeInvocation	interceptor

Properties
new double	PixelSize [get, set]
virtual System.IntPtr	SmokeObject [get, set]

Detailed Description

The QRawFont class provides access to a single physical instance of a font.

Note: QRawFont is a low level class. For most purposes QFont is a more appropriate class.

Most commonly, when presenting text in a user interface, the exact fonts used to render the characters is to some extent unknown. This can be the case for several reasons: For instance, the actual, physical fonts present on the target system could be unexpected to the developers, or the text could contain user selected styles, sizes or writing systems that are not supported by font chosen in the code.

Therefore, Qt's QFont class really represents a query for fonts. When text is interpreted, Qt will do its best to match the text to the query, but depending on the support, different fonts can be used behind the scenes.

For most use cases, this is both expected and necessary, as it minimizes the possibility of text in the user interface being undisplayable. In some cases, however, more direct control over the process might be useful. It is for these use cases the QRawFont class exists.

A QRawFont object represents a single, physical instance of a given font in a given pixel size. I.e. in the typical case it represents a set of TrueType or OpenType font tables and uses a user specified pixel size to convert metrics into logical pixel units. It can be used in combination with the QGlyphRun class to draw specific glyph indexes at specific positions, and also have accessors to some relevant data in the physical font.

QRawFont only provides support for the main font technologies: GDI and DirectWrite on Windows platforms, FreeType on Symbian and Linux platforms and CoreText on Mac OS X. For other font back-ends, the APIs will be disabled.

QRawFont can be constructed in a number of ways:

It can be constructed by calling QTextLayout::glyphs() or QTextFragment::glyphs(). The returned QGlyphs objects will contain QRawFont objects which represent the actual fonts used to render each portion of the text.

It can be constructed by passing a QFont object to QRawFont::fromFont(). The function will return a QRawFont object representing the font that will be selected as response to the QFont query and the selected writing system.

It can be constructed by passing a file name or QByteArray directly to the QRawFont constructor, or by calling loadFromFile() or loadFromData(). In this case, the font will not be registered in QFontDatabase, and it will not be available as part of regular font selection.

QRawFont is considered local to the thread in which it is constructed (either using a constructor, or by calling loadFromData() or loadFromFile()). The QRawFont cannot be moved to a different thread, but will have to be recreated in the thread in question.

Note: For the requirement of caching glyph indexes and font selections for static text to avoid reshaping and relayouting in the inner loop of an application, a better choice is the QStaticText class, since it optimizes the memory cost of the cache and also provides the possibility of paint engine specific caches for an additional speed-up.

Member Enumeration Documentation

enum QtGui.QRawFont.AntialiasingType

This enum represents the different ways a glyph can be rasterized in the function alphaMapForGlyph().

Enumerator:

PixelAntialiasing	Will rasterize by measuring the coverage of the shape on whole pixels. The returned image contains the alpha values of each pixel based on the coverage of the glyph shape.
SubPixelAntialiasing	Will rasterize by measuring the coverage of each subpixel, returning a separate alpha value for each of the red, green and blue components of each pixel.

Constructor & Destructor Documentation

QtGui.QRawFont.QRawFont ( System.Type  dummy )

protected

QtGui.QRawFont.QRawFont

(

)

Constructs an invalid QRawFont.

QtGui.QRawFont.QRawFont

(

QRawFont

other

)

Creates a QRawFont which is a copy of other.

QtGui.QRawFont.QRawFont	(	QByteArray	fontData,
		double	pixelSize,
		QFont.HintingPreference	hintingPreference = QFont.HintingPreference.PreferDefaultHinting
	)

Constructs an invalid QRawFont.

QtGui.QRawFont.QRawFont	(	string	fileName,
		double	pixelSize,
		QFont.HintingPreference	hintingPreference = QFont.HintingPreference.PreferDefaultHinting
	)

Constructs an invalid QRawFont.

Member Function Documentation

new bool QtGui.QRawFont.AdvancesForGlyphIndexes	(	ref uint	glyphIndexes,
		QPointF	advances,
		int	numGlyphs
	)

Returns the QRawFont's advances for each of the glyphIndexes in pixel units. The advances give the distance from the position of a given glyph to where the next glyph should be drawn to make it appear as if the two glyphs are unspaced.

See also QTextLine::horizontalAdvance() and QFontMetricsF::width().

new System.Collections.Generic.List<QPointF> QtGui.QRawFont.AdvancesForGlyphIndexes

(

System.Collections.Generic.List< System.UInt32 >

glyphIndexes

)

Returns the QRawFont's advances for each of the glyphIndexes in pixel units. The advances give the distance from the position of a given glyph to where the next glyph should be drawn to make it appear as if the two glyphs are unspaced.

See also QTextLine::horizontalAdvance() and QFontMetricsF::width().

new QImage QtGui.QRawFont.AlphaMapForGlyph	(	uint	glyphIndex,
		QRawFont.AntialiasingType	antialiasingType = QRawFont.AntialiasingType.SubPixelAntialiasing
	)

This function returns a rasterized image of the glyph at the given glyphIndex in the underlying font, using the transform specified. If the QRawFont is not valid, this function will return an invalid QImage.

If antialiasingType is set to QRawFont::SubPixelAntialiasing, then the resulting image will be in QImage::Format_RGB32 and the RGB values of each pixel will represent the subpixel opacities of the pixel in the rasterization of the glyph. Otherwise, the image will be in the format of QImage::Format_Indexed8 and each pixel will contain the opacity of the pixel in the rasterization.

See also pathForGlyph() and QPainter::drawGlyphRun().

new QImage QtGui.QRawFont.AlphaMapForGlyph	(	uint	glyphIndex,
		QRawFont.AntialiasingType	antialiasingType,
		QTransform	transform
	)

This function returns a rasterized image of the glyph at the given glyphIndex in the underlying font, using the transform specified. If the QRawFont is not valid, this function will return an invalid QImage.

If antialiasingType is set to QRawFont::SubPixelAntialiasing, then the resulting image will be in QImage::Format_RGB32 and the RGB values of each pixel will represent the subpixel opacities of the pixel in the rasterization of the glyph. Otherwise, the image will be in the format of QImage::Format_Indexed8 and each pixel will contain the opacity of the pixel in the rasterization.

See also pathForGlyph() and QPainter::drawGlyphRun().

new double QtGui.QRawFont.Ascent

(

)

Returns the ascent of this QRawFont in pixel units.

See also QFontMetricsF::ascent().

new double QtGui.QRawFont.AverageCharWidth

(

)

Returns the average character width of this QRawFont in pixel units.

See also QFontMetricsF::averageCharWidth().

virtual void QtGui.QRawFont.CreateProxy ( )

virtual

new double QtGui.QRawFont.Descent

(

)

Returns the descent of this QRawFont in pixel units.

See also QFontMetricsF::descent().

new void QtGui.QRawFont.Dispose

(

)

override bool QtGui.QRawFont.Equals

(

object

o

)

new string QtGui.QRawFont.FamilyName

(

)

Returns the family name of this QRawFont.

new QByteArray QtGui.QRawFont.FontTable

(

string

tagName

)

Retrieves the sfnt table named tagName from the underlying physical font, or an empty byte array if no such table was found. The returned font table's byte order is Big Endian, like the sfnt format specifies. The tagName must be four characters long and should be formatted in the default endianness of the current platform.

static QRawFont QtGui.QRawFont.FromFont ( QFont  font, QFontDatabase.WritingSystem  writingSystem = QFontDatabase.WritingSystem.Any  )

static

Fetches the physical representation based on a font query. The physical font returned is the font that will be preferred by Qt in order to display text in the selected writingSystem.

override int QtGui.QRawFont.GetHashCode

(

)

new bool QtGui.QRawFont.GlyphIndexesForChars	(	QChar	chars,
		int	numChars,
		ref uint	glyphIndexes,
		ref int	numGlyphs
	)

Converts a string of unicode points to glyph indexes using the CMAP table in the underlying font. The function works like glyphIndexesForString() except it take an array (chars), the results will be returned though glyphIndexes array and number of glyphs will be set in numGlyphs. The size of glyphIndexes array must be at least numChars, if that's still not enough, this function will return false, then you can resize glyphIndexes from the size returned in numGlyphs.

See also glyphIndexesForString(), advancesForGlyphIndexes(), QGlyphRun, QTextLayout::glyphRuns(), and QTextFragment::glyphRuns().

new System.Collections.Generic.List<System.UInt32> QtGui.QRawFont.GlyphIndexesForString

(

string

text

)

Converts the string of unicode points given by text to glyph indexes using the CMAP table in the underlying font, and returns a vector containing the result.

Note that, in cases where there are other tables in the font that affect the shaping of the text, the returned glyph indexes will not correctly represent the rendering of the text. To get the correctly shaped text, you can use QTextLayout to lay out and shape the text, then call QTextLayout::glyphs() to get the set of glyph index list and QRawFont pairs.

See also advancesForGlyphIndexes(), glyphIndexesForChars(), QGlyphRun, QTextLayout::glyphRuns(), and QTextFragment::glyphRuns().

new QFont.HintingPreference QtGui.QRawFont.HintingPreference

(

)

Returns the hinting preference used to construct this QRawFont.

See also QFont::hintingPreference().

new bool QtGui.QRawFont.IsValid

(

)

Returns true if the QRawFont is valid and false otherwise.

new double QtGui.QRawFont.Leading

(

)

Returns the leading of this QRawFont in pixel units.

See also QFontMetricsF::leading().

new void QtGui.QRawFont.LoadFromData	(	QByteArray	fontData,
		double	pixelSize,
		QFont.HintingPreference	hintingPreference
	)

Replaces the current QRawFont with the font contained in the supplied fontData for the size (in pixels) given by pixelSize, and using the hinting preference specified by hintingPreference.

The fontData must contain a TrueType or OpenType font.

See also loadFromFile().

new void QtGui.QRawFont.LoadFromFile	(	string	fileName,
		double	pixelSize,
		QFont.HintingPreference	hintingPreference
	)

Replaces the current QRawFont with the contents of the file referenced by fileName for the size (in pixels) given by pixelSize, and using the hinting preference specified by hintingPreference.

The file must reference a TrueType or OpenType font.

See also loadFromData().

new double QtGui.QRawFont.MaxCharWidth

(

)

Returns the width of the widest character in the font.

See also QFontMetricsF::maxWidth().

static bool QtGui.QRawFont.operator!= ( QRawFont  arg1, QRawFont  arg2  )

static

Returns true if this QRawFont is not equal to other. Otherwise, returns false.

static bool QtGui.QRawFont.operator== ( QRawFont  arg1, QRawFont  arg2  )

static

Returns true if this QRawFont is equal to other. Otherwise, returns false.

new QPainterPath QtGui.QRawFont.PathForGlyph

(

uint

glyphIndex

)

This function returns the shape of the glyph at a given glyphIndex in the underlying font if the QRawFont is valid. Otherwise, it returns an empty QPainterPath.

The returned glyph will always be unhinted.

See also alphaMapForGlyph() and QPainterPath::addText().

new QFont.Style QtGui.QRawFont.Style

(

)

Returns the style of this QRawFont.

See also QFont::style().

new string QtGui.QRawFont.StyleName

(

)

Returns the style name of this QRawFont.

See also QFont::styleName().

new System.Collections.Generic.List<QFontDatabase.WritingSystem> QtGui.QRawFont.SupportedWritingSystems

(

)

Returns a list of writing systems supported by the font according to designer supplied information in the font file. Please note that this does not guarantee support for a specific unicode point in the font. You can use the supportsCharacter() to check support for a single, specific character.

Note: The list is determined based on the unicode ranges and codepage ranges set in the font's OS/2 table and requires such a table to be present in the underlying font file.

See also supportsCharacter().

new bool QtGui.QRawFont.SupportsCharacter

(

QChar

character

)

Returns true if the font has a glyph that corresponds to the given character.

See also supportedWritingSystems().

new bool QtGui.QRawFont.SupportsCharacter

(

uint

ucs4

)

Returns true if the font has a glyph that corresponds to the given character.

See also supportedWritingSystems().

new double QtGui.QRawFont.UnitsPerEm

(

)

Returns the number of design units define the width and height of the em square for this QRawFont. This value is used together with the pixel size when converting design metrics to pixel units, as the internal metrics are specified in design units and the pixel size gives the size of 1 em in pixels.

See also pixelSize() and setPixelSize().

new int QtGui.QRawFont.Weight

(

)

Returns the weight of this QRawFont.

See also QFont::weight().

new double QtGui.QRawFont.xHeight

(

)

Returns the xHeight of this QRawFont in pixel units.

See also QFontMetricsF::xHeight().

Member Data Documentation

SmokeInvocation QtGui.QRawFont.interceptor

protected

Property Documentation

new double QtGui.QRawFont.PixelSize

getset

Returns the pixel size set for this QRawFont. The pixel size affects how glyphs are rasterized, the size of glyphs returned by pathForGlyph(), and is used to convert internal metrics from design units to logical pixel units.

Sets the pixel size with which this font should be rendered to pixelSize.

virtual System.IntPtr QtGui.QRawFont.SmokeObject

getset