QFont 类

QFont 类指定用于绘制文本的字体查询。 更多...

头：	#include <QFont>
CMake:	find_package(Qt6 REQUIRED COMPONENTS Gui) target_link_libraries(mytarget PRIVATE Qt6::Gui)
qmake:	QT += gui

• 所有成员列表，包括继承成员
• 弃用成员
• QFont 属于 描绘类 , 隐式共享类 ，和 富文本处理 API .

注意： 此类的所有函数 可重入 .

公共类型

(从 6.7 起) struct	Tag
enum	Capitalization { MixedCase, AllUppercase, AllLowercase, SmallCaps, Capitalize }
enum	HintingPreference { PreferDefaultHinting, PreferNoHinting, PreferVerticalHinting, PreferFullHinting }
enum	SpacingType { PercentageSpacing, AbsoluteSpacing }
enum	Stretch { AnyStretch, UltraCondensed, ExtraCondensed, Condensed, SemiCondensed, …, UltraExpanded }
enum	Style { StyleNormal, StyleItalic, StyleOblique }
enum	StyleHint { AnyStyle, SansSerif, Helvetica, Serif, Times, …, System }
enum	StyleStrategy { PreferDefault, PreferBitmap, PreferDevice, PreferOutline, ForceOutline, …, PreferQuality }
enum	Weight { Thin, ExtraLight, Light, Normal, Medium, …, Black }

公共函数

	QFont ()
	QFont (const QString & family , int pointSize = -1, int weight = -1, bool italic = false)
	QFont (const QStringList & families , int pointSize = -1, int weight = -1, bool italic = false)
	QFont (const QFont & font , const QPaintDevice * pd )
	QFont (const QFont & font )
	~QFont ()
bool	bold () const
QFont::Capitalization	capitalization () const
(从 6.7 起) void	clearFeatures ()
(从 6.7 起) void	clearVariableAxes ()
QString	defaultFamily () const
bool	exactMatch () const
QStringList	families () const
QString	family () const
(从 6.7 起) QList<QFont::Tag>	featureTags () const
(从 6.7 起) quint32	featureValue (QFont::Tag tag ) const
bool	fixedPitch () const
bool	fromString (const QString & descrip )
QFont::HintingPreference	hintingPreference () const
bool	isCopyOf (const QFont & f ) const
(从 6.7 起) bool	isFeatureSet (QFont::Tag tag ) const
(从 6.7 起) bool	isVariableAxisSet (QFont::Tag tag ) const
bool	italic () const
bool	kerning () const
QString	key () const
qreal	letterSpacing () const
QFont::SpacingType	letterSpacingType () const
bool	overline () const
int	pixelSize () const
int	pointSize () const
qreal	pointSizeF () const
QFont	resolve (const QFont & other ) const
void	setBold (bool enable )
void	setCapitalization (QFont::Capitalization caps )
void	setFamilies (const QStringList & families )
void	setFamily (const QString & family )
(从 6.7 起) void	setFeature (QFont::Tag tag , quint32 value )
void	setFixedPitch (bool enable )
void	setHintingPreference (QFont::HintingPreference hintingPreference )
void	setItalic (bool enable )
void	setKerning (bool enable )
void	setLetterSpacing (QFont::SpacingType type , qreal spacing )
void	setOverline (bool enable )
void	setPixelSize (int pixelSize )
void	setPointSize (int pointSize )
void	setPointSizeF (qreal pointSize )
void	setStretch (int factor )
void	setStrikeOut (bool enable )
void	setStyle (QFont::Style style )
void	setStyleHint (QFont::StyleHint hint , QFont::StyleStrategy strategy = PreferDefault)
void	setStyleName (const QString & styleName )
void	setStyleStrategy (QFont::StyleStrategy s )
void	setUnderline (bool enable )
(从 6.7 起) void	setVariableAxis (QFont::Tag tag , float value )
void	setWeight (QFont::Weight weight )
void	setWordSpacing (qreal spacing )
int	stretch () const
bool	strikeOut () const
QFont::Style	style () const
QFont::StyleHint	styleHint () const
QString	styleName () const
QFont::StyleStrategy	styleStrategy () const
void	swap (QFont & other )
QString	toString () const
bool	underline () const
(从 6.7 起) void	unsetFeature (QFont::Tag tag )
(从 6.7 起) void	unsetVariableAxis (QFont::Tag tag )
(从 6.7 起) QList<QFont::Tag>	variableAxisTags () const
(从 6.7 起) float	variableAxisValue (QFont::Tag tag ) const
QFont::Weight	weight () const
qreal	wordSpacing () const
QVariant	operator QVariant () const
bool	operator!= (const QFont & f ) const
bool	operator< (const QFont & f ) const
QFont &	operator= (const QFont & font )
QFont &	operator= (QFont && other )
bool	operator== (const QFont & f ) const

静态公共成员

void	insertSubstitution (const QString & familyName , const QString & substituteName )
void	insertSubstitutions (const QString & familyName , const QStringList & substituteNames )
void	removeSubstitutions (const QString & familyName )
QString	substitute (const QString & familyName )
QStringList	substitutes (const QString & familyName )
QStringList	substitutions ()

相关非成员

size_t	qHash (const QFont & font , size_t seed = 0)
QDataStream &	operator<< (QDataStream & s , const QFont & font )
QDataStream &	operator>> (QDataStream & s , QFont & font )

详细描述

可以将 QFont 视为是对系统中一种 (或多种) 字体的查询。

当创建 QFont 对象时，可指定想要字体拥有的各种属性。Qt 将使用带有指定属性的字体，或者若不存在匹配字体，Qt 将使用最接近匹配的安装字体。实际使用的字体属性检索自 QFontInfo 对象。若窗口系统提供的准确匹配 exactMatch () 返回 true 。使用 QFontMetricsF 能获取度量值，如字符串的像素长度是使用 QFontMetrics::width()。

未具体设置的属性不影响字体选择算法，而是以首选默认值代替。

要加载通常由单文件表示的特定物理字体，使用 QRawFont 代替。

注意， QGuiApplication instance must exist before a QFont can be used. You can set the application's default font with QGuiApplication::setFont ().

If a chosen font does not include all the characters that need to be displayed, QFont will try to find the characters in the nearest equivalent fonts. When a QPainter draws a character from a font the QFont will report whether or not it has the character; if it does not, QPainter 将绘制未填充正方形。

创建 QFont 像这样：

QFont serifFont("Times", 10, QFont::Bold);
QFont sansFont("Helvetica [Cronyx]", 12);
					

在构造函数中设置的属性也可以稍后设置，如 setFamily (), setPointSize (), setPointSizeF (), setWeight () 和 setItalic ()。其余属性必须在构造后设置，如 setBold (), setUnderline (), setOverline (), setStrikeOut () 和 setFixedPitch (). QFontInfo 对象应该被创建 after 字体属性已设置。 QFontInfo 对象不改变，即使更改字体的属性。相应 get 函数，如 family (), pointSize () 等，返回设置值，即使使用的值可能不同。实际值可以获取自 QFontInfo 对象。

若请求字体系列不可用，可以影响 字体匹配算法 通过选取特定 QFont::StyleHint and QFont::StyleStrategy with setStyleHint ()。默认系列 (对应当前样式提示) 的返回是通过 defaultFamily ().

You can provide substitutions for font family names using insertSubstitution () 和 insertSubstitutions ()。可以移除代入采用 removeSubstitutions ()。使用 substitute () 检索系列的第一代入，或检索系列名称自身若没有代入。使用 substitutes () to retrieve a list of a family's substitutes (which may be empty). After substituting a font, you must trigger the updating of the font by destroying and re-creating all QFont objects.

Every QFont has a key () which you can use, for example, as the key in a cache or dictionary. If you want to store a user's font preferences you could use QSettings , writing the font information with toString () and reading it back with fromString (). The operator<<() and operator>>() functions are also available, but they work on a data stream.

It is possible to set the height of characters shown on the screen to a specified number of pixels with setPixelSize (); however using setPointSize () has a similar effect and provides device independence.

Loading fonts can be expensive, especially on X11. QFont contains extensive optimizations to make the copying of QFont objects fast, and to cache the results of the slow window system functions it depends upon.

字体匹配算法工作如下：

1. 指定字体系列 (设置通过 setFamilies ()) 为搜索。
2. If not, a replacement font that supports the writing system is selected. The font matching algorithm will try to find the best match for all the properties set in the QFont. How this is done varies from platform to platform.
3. If no font exists on the system that can support the text, then special "missing character" boxes will be shown in its place.

注意： If the selected font, though supporting the writing system in general, is missing glyphs for one or more specific characters, then Qt will try to find a fallback font for this or these particular characters. This feature can be disabled using QFont::NoFontMerging style strategy.

In Windows a request for the "Courier" font is automatically changed to "Courier New", an improved version of Courier that allows for smooth scaling. The older "Courier" bitmap font can be selected by setting the PreferBitmap 样式对策 (见 setStyleStrategy ()).

一旦找到字体，剩余属性将按优先级次序匹配：

1. fixedPitch ()
2. pointSize () (见下文)
3. weight ()
4. style ()

If you have a font which matches on family, even if none of the other attributes match, this font will be chosen in preference to a font which doesn't match on family but which does match on the other attributes. This is because font family is the dominant search criteria.

The point size is defined to match if it is within 20% of the requested point size. When several fonts match and are only distinguished by point size, the font with the closest point size to the one requested will be chosen.

The actual family, font size, weight and other font attributes used for drawing text will depend on what's available for the chosen family under the window system. A QFontInfo object can be used to determine the actual values used for drawing the text.

范例：

QFont f("Helvetica");
					

若拥有 Adobe 和 Cronyx Helvetica 两者，可以获取任一。

QFont f("Helvetica [Cronyx]");
					

You can specify the foundry you want in the family name. The font f in the above example will be set to "Helvetica [Cronyx]".

To determine the attributes of the font actually used in the window system, use a QFontInfo 对象，如

QFontInfo info(f1);
QString family = info.family();
					

要找出字体规格，使用 QFontMetrics 对象，如

QFontMetrics fm(f1);
int textWidthInPixels = fm.horizontalAdvance("How many pixels wide is this text?");
int textHeightInPixels = fm.height();
					

对于字体的更多一般信息，见 comp.fonts FAQ 。有关编码的信息可以找到从 UTR17 页面。

另请参阅 QFontMetrics , QFontInfo ，和 QFontDatabase .

成员类型文档编制

enum QFont:: Capitalization

此字体应用于文本的渲染选项。

常量	值	描述
QFont::MixedCase	0	This is the normal text rendering option where no capitalization change is applied.
QFont::AllUppercase	1	这以全大写类型方式更改要渲染文本。
QFont::AllLowercase	2	这以全小写类型方式更改要渲染文本。
QFont::SmallCaps	3	This alters the text to be rendered in small-caps type.
QFont::Capitalize	4	This alters the text to be rendered with the first character of each word as an uppercase character.

enum QFont:: HintingPreference

This enum describes the different levels of hinting that can be applied to glyphs to improve legibility on displays where it might be warranted by the density of pixels.

常量	值	描述
QFont::PreferDefaultHinting	0	Use the default hinting level for the target platform.
QFont::PreferNoHinting	1	If possible, render text without hinting the outlines of the glyphs. The text layout will be typographically accurate and scalable, using the same metrics as are used e.g. when printing.
QFont::PreferVerticalHinting	2	If possible, render text with no horizontal hinting, but align glyphs to the pixel grid in the vertical direction. The text will appear crisper on displays where the density is too low to give an accurate rendering of the glyphs. But since the horizontal metrics of the glyphs are unhinted, the text's layout will be scalable to higher density devices (such as printers) without impacting details such as line breaks.
QFont::PreferFullHinting	3	If possible, render text with hinting in both horizontal and vertical directions. The text will be altered to optimize legibility on the target device, but since the metrics will depend on the target size of the text, the positions of glyphs, line breaks, and other typographical detail will not scale, meaning that a text layout may look different on devices with different pixel densities.

Please note that this enum only describes a preference, as the full range of hinting levels are not supported on all of Qt's supported platforms. The following table details the effect of a given hinting preference on a selected set of target platforms.

	PreferDefaultHinting	PreferNoHinting	PreferVerticalHinting	PreferFullHinting
Windows and DirectWrite enabled in Qt	完整提示	垂直提示	垂直提示	完整提示
FreeType	操作系统设置	不提示	Vertical hinting (light)	完整提示
在 macOS 的 Cocoa	不提示	不提示	不提示	不提示

enum QFont:: SpacingType

常量	值	描述
QFont::PercentageSpacing	0	值 100 将保持间距不变；值 200 将字符后间距扩大到字符本身宽度。
QFont::AbsoluteSpacing	1	正值递增相应像素的字母间距；负值递减间距。

enum QFont:: Stretch

遵循 CSS 命名约定的预定义拉伸值。值越高，文本拉伸更多。

常量	值	描述
QFont::AnyStretch (since Qt 5.8)	0	0 接受任何拉伸匹配使用其它 QFont properties
QFont::UltraCondensed	50	50
QFont::ExtraCondensed	62	62
QFont::Condensed	75	75
QFont::SemiCondensed	87	87
QFont::Unstretched	100	100
QFont::SemiExpanded	112	112
QFont::Expanded	125	125
QFont::ExtraExpanded	150	150
QFont::UltraExpanded	200	200

另请参阅 setStretch () 和 stretch ().

enum QFont:: Style

此枚举描述用于显示文本的不同字形样式。

常量	值	描述
QFont::StyleNormal	0	用于无样式文本的 Normal (正常) 字形。
QFont::StyleItalic	1	为斜体文本表示目的，专门设计的 Italic (斜体) 字形。
QFont::StyleOblique	2	具有斜体外观的字形通常是基于无样式的字形，但未对斜体文本表示目的进行微调。

另请参阅 Weight .

enum QFont:: StyleHint

样式提示用于 字体匹配 算法以查找适当默认系列，若选中的字体系列不可用。

常量	值	描述
QFont::AnyStyle	5	让字体匹配算法选择系列。这为默认。
QFont::SansSerif	Helvetica	字体匹配器首选 SansSerif 字体。
QFont::Helvetica	0	同义词 SansSerif .
QFont::Serif	Times	字体匹配器首选 serif 字体。
QFont::Times	1	同义词 Serif .
QFont::TypeWriter	Courier	字体匹配器首选固定间距字体。
QFont::Courier	2	同义词 TypeWriter .
QFont::OldEnglish	3	字体匹配器首选装饰字体。
QFont::Decorative	OldEnglish	同义词 OldEnglish .
QFont::Monospace	7	字体匹配器首选映射到 CSS 一般字体系列 Monospace (等宽) 的字体。
QFont::Fantasy	8	字体匹配器首选映射到 CSS 一般字体系列 Fantasy (幻想) 的字体。
QFont::Cursive	6	字体匹配器首选映射到 CSS 一般字体系列 Cursive (草书) 的字体。
QFont::System	4	字体匹配器首选系统字体。

enum QFont:: StyleStrategy

样式对策告诉 字体匹配 算法应使用什么类型字体以查找合适默认系列。

下列对策可用：

常量	值	描述
QFont::PreferDefault	0x0001	默认样式战略。它不首选任何类型的字体。
QFont::PreferBitmap	0x0002	首选位图字体 (而不是轮廓字体)。
QFont::PreferDevice	0x0004	首选设备字体。
QFont::PreferOutline	0x0008	首选轮廓字体 (而不是位图字体)。
QFont::ForceOutline	0x0010	强制使用轮廓字体。
QFont::NoAntialias	0x0100	不对字体抗锯齿。
QFont::NoSubpixelAntialias	0x0800	避免亚像素字体抗锯齿，若可能的话。
QFont::PreferAntialias	0x0080	抗锯齿，若可能的话。
QFont::NoFontMerging	0x8000	若为某种书写系统选择的字体不包含请求绘制的字符，那么 Qt 会自动选取包含该字符的外观类似字体。NoFontMerging 标志会禁用此特征。请注意，启用此标志不会阻止 Qt 自动拾取合适字体，当所选字体不支持文本书写系统时。
QFont::PreferNoShaping	0x1000	Sometimes, a font will apply complex rules to a set of characters in order to display them correctly. In some writing systems, such as Brahmic scripts, this is required in order for the text to be legible, but in e.g. Latin script, it is merely a cosmetic feature. The PreferNoShaping flag will disable all such features when they are not required, which will improve performance in most cases (since Qt 5.10).

这些中的任何标志可以与以下标志之一 OR 组合：

常量	值	描述
QFont::PreferMatch	0x0020	首选准确匹配。字体匹配器将试着使用已指定的准确字体大小。
QFont::PreferQuality	0x0040	首选最佳品质字体。字体匹配器将使用字体支持的最接近标准点大小。

enum QFont:: Weight

Qt 使用兼容 OpenType 从 1 到 1000 的加权比例缩放。权重 1 会很瘦，而 1000 会非常黑。

此枚举包含预定义的字体粗细：

常量	值	描述
QFont::Thin	100	100
QFont::ExtraLight	200	200
QFont::Light	300	300
QFont::Normal	400	400
QFont::Medium	500	500
QFont::DemiBold	600	600
QFont::Bold	700	700
QFont::ExtraBold	800	800
QFont::Black	900	900

成员函数文档编制

QFont:: QFont ()

使用应用程序默认字体，构造字体对象。

另请参阅 QGuiApplication::setFont () 和 QGuiApplication::font ().

QFont:: QFont (const QString & family , int pointSize = -1, int weight = -1, bool italic = false)

构造字体对象采用指定 family , pointSize , weight and italic 设置。

若 pointSize 为 0 或负值，字体点大小被设为从属系统的默认值。一般来说，这是 12 点。

The family 名称还可以可选包括代工厂名称，如 Helvetica[Cronyx]。若 family 可以从多个代工厂获得但未指定代工厂，可以选择任意代工厂。若系列不可用，将设置系列使用 字体匹配 算法。

This will split the family string on a comma and call setFamilies () with the resulting list. To preserve a font that uses a comma in its name, use the constructor that takes a QStringList .

另请参阅 Weight , setFamily (), setPointSize (), setWeight (), setItalic (), setStyleHint (), setFamilies ()，和 QGuiApplication::font ().

[explicit] QFont:: QFont (const QStringList & families , int pointSize = -1, int weight = -1, bool italic = false)

构造字体对象采用指定 families , pointSize , weight and italic 设置。

若 pointSize 为 0 或负值，字体点大小被设为从属系统的默认值。一般来说，这是 12 点。

Each family name entry in families may optionally also include a foundry name, e.g. "Helvetica [Cronyx]". If the family is available from more than one foundry and the foundry isn't specified, an arbitrary foundry is chosen. If the family isn't available a family will be set using the 字体匹配 算法。

另请参阅 Weight , setPointSize (), setWeight (), setItalic (), setStyleHint (), setFamilies ()，和 QGuiApplication::font ().

QFont:: QFont (const QFont & font , const QPaintDevice * pd )

构造字体从 font 为用于描绘设备 pd .

QFont:: QFont (const QFont & font )

构造副本字体为 font .

[noexcept] QFont:: ~QFont ()

销毁字体对象并释放所有分配资源。

bool QFont:: bold () const

返回 true if weight () 值大于 QFont::Medium ；否则返回 false .

另请参阅 weight (), setBold ()，和 QFontInfo::bold ().

QFont::Capitalization QFont:: capitalization () const

返回字体的当前大写类型。

另请参阅 setCapitalization ().

[since 6.7] void QFont:: clearFeatures ()

Clears any previously set features on the QFont .

见 setFeature () for more details on font features.

该函数在 Qt 6.7 引入。

另请参阅 QFont::Tag , setFeature (), unsetFeature (), featureTags ()，和 featureValue ().

[since 6.7] void QFont:: clearVariableAxes ()

Clears any previously set variable axis values on the QFont .

见 setVariableAxis () for more details on variable axes.

该函数在 Qt 6.7 引入。

另请参阅 QFont::Tag , setVariableAxis (), unsetVariableAxis (), isVariableAxisSet ()，和 variableAxisValue ().

QString QFont:: defaultFamily () const

返回当前样式提示对应的系列名称。

另请参阅 StyleHint , styleHint ()，和 setStyleHint ().

bool QFont:: exactMatch () const

返回 true 若窗口系统字体准确匹配此字体的设置是可用的。

另请参阅 QFontInfo .

QStringList QFont:: families () const

Returns the requested font family names, i.e. the names set in the last setFamilies () call or via the constructor. Otherwise it returns an empty list.

另请参阅 setFamily (), setFamilies (), family (), substitutes ()，和 substitute ().

QString QFont:: family () const

返回请求的字体系列名称。这将始终相同如第一条目在 families () 调用。

另请参阅 setFamily (), substitutes (), substitute (), setFamilies ()，和 families ().

[since 6.7] QList < QFont::Tag > QFont:: featureTags () const

Returns a list of tags for all font features currently set on this QFont .

见 setFeature () for more details on font features.

该函数在 Qt 6.7 引入。

另请参阅 QFont::Tag , setFeature (), unsetFeature (), isFeatureSet ()，和 clearFeatures ().

[since 6.7] quint32 QFont:: featureValue ( QFont::Tag tag ) const

Returns the value set for a specific feature tag . If the tag has not been set, 0 will be returned instead.

见 setFeature () for more details on font features.

该函数在 Qt 6.7 引入。

另请参阅 QFont::Tag , setFeature (), unsetFeature (), featureTags ()，和 isFeatureSet ().

bool QFont:: fixedPitch () const

返回 true 若有设置固定间距；否则返回 false .

另请参阅 setFixedPitch () 和 QFontInfo::fixedPitch ().

bool QFont:: fromString (const QString & descrip )

设置此字体以匹配描述 descrip . The description is a comma-separated list of the font attributes, as returned by toString ().

另请参阅 toString ().

QFont::HintingPreference QFont:: hintingPreference () const

返回目前采用此字体，渲染字形的首选提示级别。

另请参阅 setHintingPreference ().

[static] void QFont:: insertSubstitution (const QString & familyName , const QString & substituteName )

插入 substituteName 进代入表为系列 familyName .

After substituting a font, trigger the updating of the font by destroying and re-creating all QFont 对象。

另请参阅 insertSubstitutions (), removeSubstitutions (), substitutions (), substitute ()，和 substitutes ().

[static] void QFont:: insertSubstitutions (const QString & familyName , const QStringList & substituteNames )

Inserts the list of families substituteNames into the substitution list for familyName .

After substituting a font, trigger the updating of the font by destroying and re-creating all QFont 对象。

另请参阅 insertSubstitution (), removeSubstitutions (), substitutions ()，和 substitute ().

bool QFont:: isCopyOf (const QFont & f ) const

返回 true if this font and f are copies of each other, i.e. one of them was created as a copy of the other and neither has been modified since. This is much stricter than equality.

另请参阅 operator= () 和 operator== ().

[since 6.7] bool QFont:: isFeatureSet ( QFont::Tag tag ) const

Returns true if a value for the feature given by tag has been set on the QFont ，否则返回 false。

见 setFeature () for more details on font features.

该函数在 Qt 6.7 引入。

另请参阅 QFont::Tag , setFeature (), unsetFeature (), featureTags ()，和 featureValue ().

[since 6.7] bool QFont:: isVariableAxisSet ( QFont::Tag tag ) const

Returns true if a value for the variable axis given by tag has been set on the QFont ，否则返回 false。

见 setVariableAxis () for more details on font variable axes.

该函数在 Qt 6.7 引入。

另请参阅 QFont::Tag , setVariableAxis (), unsetVariableAxis (), variableAxisValue ()，和 clearVariableAxes ().

bool QFont:: italic () const

返回 true 若 style () of the font is not QFont::StyleNormal

另请参阅 setItalic () 和 style ().

bool QFont:: kerning () const

返回 true 若应使用字距，当采用此字体绘制文本时。

另请参阅 setKerning ().

QString QFont:: key () const

Returns the font's key, a textual representation of a font. It is typically used as the key for a cache or dictionary of fonts.

另请参阅 QMap .

qreal QFont:: letterSpacing () const

返回字体的字母间距。

另请参阅 setLetterSpacing (), letterSpacingType ()，和 setWordSpacing ().

QFont::SpacingType QFont:: letterSpacingType () const

返回用于字母间距的间距类型。

另请参阅 letterSpacing (), setLetterSpacing ()，和 setWordSpacing ().

bool QFont:: overline () const

返回 true 若有设置上划线；否则返回 false .

另请参阅 setOverline ().

int QFont:: pixelSize () const

返回字体的像素大小，若它有设置采用 setPixelSize ()。返回 -1 若大小的设置是采用 setPointSize () 或 setPointSizeF ().

另请参阅 setPixelSize (), pointSize (), QFontInfo::pointSize ()，和 QFontInfo::pixelSize ().

int QFont:: pointSize () const

返回字体的点大小。返回 -1 若以像素为单位指定字体大小。

另请参阅 setPointSize () 和 pointSizeF ().

qreal QFont:: pointSizeF () const

返回字体的点大小。返回 -1 若以像素为单位指定字体大小。

另请参阅 pointSize (), setPointSizeF (), pixelSize (), QFontInfo::pointSize ()，和 QFontInfo::pixelSize ().

[static] void QFont:: removeSubstitutions (const QString & familyName )

移除所有代入为 familyName .

另请参阅 insertSubstitutions (), insertSubstitution (), substitutions ()，和 substitute ().

QFont QFont:: resolve (const QFont & other ) const

返回新的 QFont that has attributes copied from other that have not been previously set on this font.

void QFont:: setBold ( bool enable )

若 enable 为 true，将字体的权重设为 QFont::Bold ；否则将精细设为 QFont::Normal .

对于更精细粗体控制，使用 setWeight ().

注意： 若 styleName () 有设置，此值可能被忽略，或者若平台支持，字体被人为加粗。

另请参阅 bold () 和 setWeight ().

void QFont:: setCapitalization ( QFont::Capitalization caps )

将此字体中文本的首字母大小写设为 caps .

字体大写使文本以选中大写模式出现。

另请参阅 capitalization ().

void QFont:: setFamilies (const QStringList & families )

Sets the list of family names for the font. The names are case insensitive and may include a foundry name. The first family in families will be set as the main family for the font.

Each family name entry in families may optionally also include a foundry name, e.g. "Helvetica [Cronyx]". If the family is available from more than one foundry and the foundry isn't specified, an arbitrary foundry is chosen. If the family isn't available a family will be set using the 字体匹配 算法。

另请参阅 family (), families (), setFamily (), setStyleHint ()，和 QFontInfo .

void QFont:: setFamily (const QString & family )

设置字体的系列名称。名称不区分大小写且可能包括出厂名称。

The family 名称还可以可选包括代工厂名称，如 Helvetica[Cronyx]。若 family 可以从多个代工厂获得但未指定代工厂，可以选择任意代工厂。若系列不可用，将设置系列使用 字体匹配 算法。

另请参阅 family (), setStyleHint (), setFamilies (), families ()，和 QFontInfo .

[since 6.7] void QFont:: setFeature ( QFont::Tag tag , quint32 value )

这是重载函数。

Applies an integer value to the typographical feature specified by tag when shaping the text. This provides advanced access to the font shaping process, and can be used to support font features that are otherwise not covered in the API.

The feature is specified by a tag , which is typically encoded from the four-character feature name in the font feature map.

This integer value passed along with the tag in most cases represents a boolean value: A zero value means the feature is disabled, and a non-zero value means it is enabled. For certain font features, however, it may have other interpretations. For example, when applied to the salt feature, the value is an index that specifies the stylistic alternative to use.

例如， frac font feature will convert diagonal fractions separated with a slash (such as 1/2 ) with a different representation. Typically this will involve baking the full fraction into a single character width (such as ½ ).

If a font supports the frac feature, then it can be enabled in the shaper by setting features["frac"] = 1 in the font feature map.

注意： By default, Qt will enable and disable certain font features based on other font properties. In particular, the kern feature will be enabled/disabled depending on the kerning () property of the QFont . In addition, all ligature features ( liga , clig , dlig , hlig ) will be disabled if a letterSpacing () is applied, but only for writing systems where the use of ligature is cosmetic. For writing systems where ligatures are required, the features will remain in their default state. The values set using setFeature() and related functions will override the default behavior. If, for instance, the feature "kern" is set to 1, then kerning will always be enabled, regardless of whether the kerning property is set to false. Similarly, if it is set to 0, then it will always be disabled. To reset a font feature to its default behavior, you can unset it using unsetFeature ().

该函数在 Qt 6.7 引入。

另请参阅 QFont::Tag , clearFeatures (), setFeature(), unsetFeature ()，和 featureTags ().

void QFont:: setFixedPitch ( bool enable )

若 enable 为 true，设置固定间距开；否则设置固定间距关。

另请参阅 fixedPitch () 和 QFontInfo .

void QFont:: setHintingPreference ( QFont::HintingPreference hintingPreference )

将字形提示级别首选设为 hintingPreference . This is a hint to the underlying font rendering system to use a certain level of hinting, and has varying support across platforms. See the table in the documentation for QFont::HintingPreference 了解更多细节。

默认提示首选 QFont::PreferDefaultHinting .

另请参阅 hintingPreference ().

void QFont:: setItalic ( bool enable )

设置 style () 为字体到 QFont::StyleItalic if enable 为 true；否则样式被设为 QFont::StyleNormal .

注意： 若 styleName () 有设置，此值可能被忽略，或若平台支持，字体可能倾斜渲染，而不是拾取设计的斜体字体变体。

另请参阅 italic () 和 QFontInfo .

void QFont:: setKerning ( bool enable )

为此字体启用字距调整，若 enable 为 true；否则禁用它。默认情况下，字距调整是启用的。

When kerning is enabled, glyph metrics do not add up anymore, even for Latin text. In other words, the assumption that width('a') + width('b') is equal to width("ab") is not necessarily true.

另请参阅 kerning () 和 QFontMetrics .

void QFont:: setLetterSpacing ( QFont::SpacingType type , qreal spacing )

Sets the letter spacing for the font to spacing and the type of spacing to type .

Letter spacing changes the default spacing between individual letters in the font. The spacing between the letters can be made smaller as well as larger either in percentage of the character width or in pixels, depending on the selected spacing type.

另请参阅 letterSpacing (), letterSpacingType ()，和 setWordSpacing ().

void QFont:: setOverline ( bool enable )

若 enable 为 True，设置上划线打开；否则，设置上划线关闭。

另请参阅 overline () 和 QFontInfo .

void QFont:: setPixelSize ( int pixelSize )

将字体大小设为 pixelSize pixels, with a maxiumum size of an unsigned 16-bit integer.

使用此函数使字体设备从属。使用 setPointSize () 或 setPointSizeF () 以按设备无关方式设置字体大小。

另请参阅 pixelSize ().

void QFont:: setPointSize ( int pointSize )

将点大小设为 pointSize 。点大小必须大于 0。

另请参阅 pointSize () 和 setPointSizeF ().

void QFont:: setPointSizeF ( qreal pointSize )

将点大小设为 pointSize 。点大小必须大于 0。请求精度不可能在所有平台中达成。

另请参阅 pointSizeF (), setPointSize ()，和 setPixelSize ().

void QFont:: setStretch ( int factor )

设置字体的拉伸因子。

拉伸因子匹配字体的浓缩 (或扩展) 版本，或应用拉伸变换改变字体中的所有字符的宽度按 factor 百分比。例如，设置 factor 为 150 将导致字体中的所有字符是 1.5 倍 (即 150%) 宽。最小拉伸因子为 1，最大拉伸因子为 4000。默认拉伸因子为 AnyStretch ，将接受任何拉伸因子，且不对字体应用任何变换。

拉伸因子仅应用于轮廓字体。位图字体会忽略拉伸因子。

注意： 当匹配字体与本机非默认拉伸因子时，请求拉伸 100 将把它拉伸回中等宽度字体。

另请参阅 stretch () 和 QFont::Stretch .

void QFont:: setStrikeOut ( bool enable )

若 enable 为 true，设置删除线打开；否则，设置删除线关闭。

另请参阅 strikeOut () 和 QFontInfo .

void QFont:: setStyle ( QFont::Style style )

将字体样式设为 style .

另请参阅 style (), italic ()，和 QFontInfo .

void QFont:: setStyleHint ( QFont::StyleHint hint , QFont::StyleStrategy strategy = PreferDefault)

将样式提示和对策设为 hint and strategy ，分别。

If these aren't set explicitly the style hint will default to AnyStyle and the style strategy to PreferDefault .

Qt does not support style hints on X11 since this information is not provided by the window system.

另请参阅 StyleHint , styleHint (), StyleStrategy , styleStrategy ()，和 QFontInfo .

void QFont:: setStyleName (const QString & styleName )

Sets the style name of the font to styleName . When set, other style properties like style () 和 weight () will be ignored for font matching, though they may be simulated afterwards if supported by the platform's font engine.

Due to the lower quality of artificially simulated styles, and the lack of full cross platform support, it is not recommended to use matching by style name together with matching by style properties

另请参阅 styleName ().

void QFont:: setStyleStrategy ( QFont::StyleStrategy s )

将字体样式对策设为 s .

另请参阅 styleStrategy () 和 QFont::StyleStrategy .

void QFont:: setUnderline ( bool enable )

若 enable 为 true，设置下划线开；否则设置下划线关。

另请参阅 underline () 和 QFontInfo .

[since 6.7] void QFont:: setVariableAxis ( QFont::Tag tag , float value )

Applies a value to the variable axis corresponding to tag .

Variable fonts provide a way to store multiple variations (with different weights, widths or styles) in the same font file. The variations are given as floating point values for a pre-defined set of parameters, called "variable axes". Specific instances are typically given names by the font designer, and, in Qt, these can be selected using setStyleName () just like traditional sub-families.

In some cases, it is also useful to provide arbitrary values for the different axes. For instance, if a font has a Regular and Bold sub-family, you may want a weight in-between these. You could then manually request this by supplying a custom value for the "wght" axis in the font.

QFont font;
font.setVariableAxis("wght", (QFont::Normal + QFont::Bold) / 2.0f);
					

If the "wght" axis is supported by the font and the given value is within its defined range, a font corresponding to the weight 550.0 will be provided.

There are a few standard axes than many fonts provide, such as "wght" (weight), "wdth" (width), "ital" (italic) and "opsz" (optical size). They each have indivdual ranges defined in the font itself. For instance, "wght" may span from 100 to 900 ( QFont::Thin to QFont::Black ) whereas "ital" can span from 0 to 1 (from not italic to fully italic).

A font may also choose to define custom axes; the only limitation is that the name has to meet the requirements for a QFont::Tag (sequence of four latin-1 characters.)

By default, no variable axes are set.

注意： In order to use variable axes on Windows, the application has to run with either the FreeType or DirectWrite font databases. See the documentation for QGuiApplication::QGuiApplication () for more information on how to select these technologies.

该函数在 Qt 6.7 引入。

另请参阅 unsetVariableAxis .

void QFont:: setWeight ( QFont::Weight weight )

将字体的精细设为 weight , 使用的比例缩放定义通过 QFont::Weight 枚举。

注意： 若 styleName () 有设置，此值可能被忽略对于选中字体。

另请参阅 weight () 和 QFontInfo .

void QFont:: setWordSpacing ( qreal spacing )

将字体单词间距设为 spacing .

单词间距改变单个单词之间的默认间距。正值按相应像素数量递增单词间距，而负值相应递减单词间间距。

单词间距不适用于书写系统，其单个单词不按空白分隔。

另请参阅 wordSpacing () 和 setLetterSpacing ().

int QFont:: stretch () const

返回字体的拉伸因子。

另请参阅 setStretch ().

bool QFont:: strikeOut () const

返回 true 如果有设置删除线；否则返回 false .

另请参阅 setStrikeOut ().

QFont::Style QFont:: style () const

返回字体的样式。

另请参阅 setStyle ().

QFont::StyleHint QFont:: styleHint () const

返回 StyleHint .

样式提示影响 字体匹配算法 。见 QFont::StyleHint 了解可用提示列表。

另请参阅 setStyleHint (), QFont::StyleStrategy ，和 QFontInfo::styleHint ().

QString QFont:: styleName () const

返回请求字体的样式名称。这可以用于匹配具有不规则样式 (在其它样式特性中无法被规范化) 的字体。

另请参阅 setStyleName (), setFamily ()，和 setStyle ().

QFont::StyleStrategy QFont:: styleStrategy () const

返回 StyleStrategy .

样式对策影响 字体匹配 算法。见 QFont::StyleStrategy 了解可用战略列表。

另请参阅 setStyleStrategy (), setStyleHint ()，和 QFont::StyleHint .

[static] QString QFont:: substitute (const QString & familyName )

返回要使用的第一系列名称每当 familyName 有指定。查找不区分大小写。

若没有代入对于 familyName , familyName 被返回。

要获得代入列表使用 substitutes ().

另请参阅 setFamily (), insertSubstitutions (), insertSubstitution ()，和 removeSubstitutions ().

[static] QStringList QFont:: substitutes (const QString & familyName )

返回要使用的系列名称列表每当 familyName 有指定。查找不区分大小写。

若没有代入对于 familyName ，返回空列表。

另请参阅 substitute (), insertSubstitutions (), insertSubstitution ()，和 removeSubstitutions ().

[static] QStringList QFont:: substitutions ()

返回代入系列名称的排序列表。

另请参阅 insertSubstitution (), removeSubstitutions ()，和 substitute ().

[noexcept] void QFont:: swap ( QFont & other )

交换此字体实例与 other 。此函数非常快且从不失败。

QString QFont:: toString () const

返回字体的描述。描述是逗号分隔的属性列表，非常适合用于 QSettings ，并由以下组成：

• Font family
• Point size
• Pixel size
• Style hint
• Font weight
• Font style
• Underline
• Strike out
• Fixed pitch
• Always 0
• Capitalization
• Letter spacing
• Word spacing
• Stretch
• Style strategy
• Font style (omitted when unavailable)

另请参阅 fromString ().

bool QFont:: underline () const

返回 true 若有设置下划线；否则返回 false .

另请参阅 setUnderline ().

[since 6.7] void QFont:: unsetFeature ( QFont::Tag tag )

这是重载函数。

Unsets the tag from the map of explicitly enabled/disabled features.

注意： Even if the feature has not previously been added, this will mark the font features map as modified in this QFont , so that it will take precedence when resolving against other fonts.

Unsetting an existing feature on the QFont reverts behavior to the default.

见 setFeature () for more details on font features.

该函数在 Qt 6.7 引入。

另请参阅 QFont::Tag , clearFeatures (), setFeature (), featureTags ()，和 featureValue ().

[since 6.7] void QFont:: unsetVariableAxis ( QFont::Tag tag )

Unsets a previously set variable axis value given by tag .

注意： If no value has previously been given for this tag, the QFont will still consider its variable axes as set when resolving against other QFont 值。

该函数在 Qt 6.7 引入。

另请参阅 setVariableAxis .

[since 6.7] QList < QFont::Tag > QFont:: variableAxisTags () const

Returns a list of tags for all variable axes currently set on this QFont .

见 setVariableAxis () for more details on variable axes.

该函数在 Qt 6.7 引入。

另请参阅 QFont::Tag , setVariableAxis (), unsetVariableAxis (), isVariableAxisSet ()，和 clearVariableAxes ().

[since 6.7] float QFont:: variableAxisValue ( QFont::Tag tag ) const

Returns the value set for a specific variable axis tag . If the tag has not been set, 0.0 will be returned instead.

见 setVariableAxis () for more details on variable axes.

该函数在 Qt 6.7 引入。

另请参阅 QFont::Tag , setVariableAxis (), unsetVariableAxis (), isVariableAxisSet ()，和 clearVariableAxes ().

QFont::Weight QFont:: weight () const

返回字体的权重，使用相同比例如 QFont::Weight 枚举。

另请参阅 setWeight (), Weight ，和 QFontInfo .

qreal QFont:: wordSpacing () const

返回字体的单词间距。

另请参阅 setWordSpacing () 和 setLetterSpacing ().

QVariant QFont:: operator QVariant () const

返回字体作为 QVariant

bool QFont:: operator!= (const QFont & f ) const

返回 true 若此字体不同于 f ；否则返回 false .

两 QFont 被认为不同，若它们的字体属性不同。

另请参阅 operator== ().

bool QFont:: operator< (const QFont & f ) const

提供任意比较为此字体和字体 f 。唯一保证的是运算符返回 false 若两字体相等且 (f1 < f2) == !(f2 < f1) 若字体不相等。

此函数在某些情况下很有用，例如，若想要使用 QFont 对象作为键在 QMap .

另请参阅 operator== (), operator!= ()，和 isCopyOf ().

QFont &QFont:: operator= (const QFont & font )

赋值 font 到此字体并返回它的引用。

[noexcept] QFont &QFont:: operator= ( QFont && other )

移动赋值 other 到此 QFont 实例。

bool QFont:: operator== (const QFont & f ) const

返回 true 若此字体等于 f ；否则返回 false。

两 QFont 被认为相等，若它们的字体属性相等。

另请参阅 operator!= () 和 isCopyOf ().

相关非成员

[noexcept] size_t qHash (const QFont & font , size_t seed = 0)

返回哈希值为 font 。若指定， seed 用于初始化哈希。

QDataStream & operator<< ( QDataStream & s , const QFont & font )

写入字体 font 到数据流 s . ( toString () 写入到文本流。)

另请参阅 QDataStream 运算符格式 .

QDataStream & operator>> ( QDataStream & s , QFont & font )

读取字体 font 从数据流 s . ( fromString () 读取自文本流。)

另请参阅 QDataStream 运算符格式 .

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