QFont Class
The QFont class specifies a query for a font used for drawing text. More...
| Header: | #include <QFont> |
| CMake: | find_package(Qt6 REQUIRED COMPONENTS Gui) target_link_libraries(mytarget PRIVATE Qt6::Gui) |
| qmake: | QT += gui |
- List of all members, including inherited members
- Deprecated members
- QFont is part of Painting Classes, Implicitly Shared Classes, and Rich Text Processing APIs.
Note: All functions in this class are reentrant.
Public Types
(since 6.7) 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 } |
Public Functions
| 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 |
(since 6.7) void | clearFeatures() |
(since 6.7) void | clearVariableAxes() |
| QString | defaultFamily() const |
| bool | exactMatch() const |
| QStringList | families() const |
| QString | family() const |
(since 6.7) QList<QFont::Tag> | featureTags() const |
(since 6.7) quint32 | featureValue(QFont::Tag tag) const |
| bool | fixedPitch() const |
| bool | fromString(const QString &descrip) |
| QFont::HintingPreference | hintingPreference() const |
| bool | isCopyOf(const QFont &f) const |
(since 6.7) bool | isFeatureSet(QFont::Tag tag) const |
(since 6.7) 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) |
(since 6.7) 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) |
(since 6.7) 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 |
(since 6.7) void | unsetFeature(QFont::Tag tag) |
(since 6.7) void | unsetVariableAxis(QFont::Tag tag) |
(since 6.7) QList<QFont::Tag> | variableAxisTags() const |
(since 6.7) 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 |
Static Public Members
| 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() |
Related Non-Members
| size_t | qHash(const QFont &font, size_t seed = 0) |
| QDataStream & | operator<<(QDataStream &s, const QFont &font) |
| QDataStream & | operator>>(QDataStream &s, QFont &font) |
Detailed Description
QFont can be regarded as a query for one or more fonts on the system.
When you create a QFont object you specify various attributes that you want the font to have. Qt will use the font with the specified attributes, or if no matching font exists, Qt will use the closest matching installed font. The attributes of the font that is actually used are retrievable from a QFontInfo object. If the window system provides an exact match exactMatch() returns true. Use QFontMetricsF to get measurements, e.g. the pixel length of a string using QFontMetrics::width().
Attributes which are not specifically set will not affect the font selection algorithm, and default values will be preferred instead.
To load a specific physical font, typically represented by a single file, use QRawFont instead.
Note that a 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 will draw an unfilled square.
Create QFonts like this:
The attributes set in the constructor can also be set later, e.g. setFamily(), setPointSize(), setPointSizeF(), setWeight() and setItalic(). The remaining attributes must be set after construction, e.g. setBold(), setUnderline(), setOverline(), setStrikeOut() and setFixedPitch(). QFontInfo objects should be created after the font's attributes have been set. A QFontInfo object will not change, even if you change the font's attributes. The corresponding "get" functions, e.g. family(), pointSize(), etc., return the values that were set, even though the values used may differ. The actual values are available from a QFontInfo object.
If the requested font family is unavailable you can influence the font matching algorithm by choosing a particular QFont::StyleHint and QFont::StyleStrategy with setStyleHint(). The default family (corresponding to the current style hint) is returned by defaultFamily().
You can provide substitutions for font family names using insertSubstitution() and insertSubstitutions(). Substitutions can be removed with removeSubstitutions(). Use substitute() to retrieve a family's first substitute, or the family name itself if it has no substitutes. Use 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.
The font matching algorithm works as follows:
- The specified font families (set by setFamilies()) are searched for.
- 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.
- If no font exists on the system that can support the text, then special "missing character" boxes will be shown in its place.
Note: 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 style strategy (see setStyleStrategy()).
Once a font is found, the remaining attributes are matched in order of priority:
- fixedPitch()
- pointSize() (see below)
- weight()
- 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.
Examples:
QFont f("Helvetica");
If you had both an Adobe and a Cronyx Helvetica, you might get either.
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 object, e.g.
To find out font metrics use a QFontMetrics object, e.g.
QFontMetrics fm(f1); int textWidthInPixels = fm.horizontalAdvance("How many pixels wide is this text?"); int textHeightInPixels = fm.height();
For more general information on fonts, see the comp.fonts FAQ. Information on encodings can be found from the UTR17 page.
See also QFontMetrics, QFontInfo, and QFontDatabase.
Member Type Documentation
enum QFont::Capitalization
Rendering option for text this font applies to.
| Constant | Value | Description |
|---|---|---|
QFont::MixedCase | 0 | This is the normal text rendering option where no capitalization change is applied. |
QFont::AllUppercase | 1 | This alters the text to be rendered in all uppercase type. |
QFont::AllLowercase | 2 | This alters the text to be rendered in all lowercase type. |
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.
| Constant | Value | Description |
|---|---|---|
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 | Full hinting | Vertical hinting | Vertical hinting | Full hinting |
| FreeType | Operating System setting | No hinting | Vertical hinting (light) | Full hinting |
| Cocoa on macOS | No hinting | No hinting | No hinting | No hinting |
enum QFont::SpacingType
| Constant | Value | Description |
|---|---|---|
QFont::PercentageSpacing | 0 | A value of 100 will keep the spacing unchanged; a value of 200 will enlarge the spacing after a character by the width of the character itself. |
QFont::AbsoluteSpacing | 1 | A positive value increases the letter spacing by the corresponding pixels; a negative value decreases the spacing. |
enum QFont::Stretch
Predefined stretch values that follow the CSS naming convention. The higher the value, the more stretched the text is.
| Constant | Value | Description |
|---|---|---|
QFont::AnyStretch (since Qt 5.8) | 0 | 0 Accept any stretch matched using the other 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 |
See also setStretch() and stretch().
enum QFont::Style
This enum describes the different styles of glyphs that are used to display text.
| Constant | Value | Description |
|---|---|---|
QFont::StyleNormal | 0 | Normal glyphs used in unstyled text. |
QFont::StyleItalic | 1 | Italic glyphs that are specifically designed for the purpose of representing italicized text. |
QFont::StyleOblique | 2 | Glyphs with an italic appearance that are typically based on the unstyled glyphs, but are not fine-tuned for the purpose of representing italicized text. |
See also Weight.
enum QFont::StyleHint
Style hints are used by the font matching algorithm to find an appropriate default family if a selected font family is not available.
| Constant | Value | Description |
|---|---|---|
QFont::AnyStyle | 5 | leaves the font matching algorithm to choose the family. This is the default. |
QFont::SansSerif | Helvetica | the font matcher prefer sans serif fonts. |
QFont::Helvetica | 0 | is a synonym for SansSerif. |
QFont::Serif | Times | the font matcher prefers serif fonts. |
QFont::Times | 1 | is a synonym for Serif. |
QFont::TypeWriter | Courier | the font matcher prefers fixed pitch fonts. |
QFont::Courier | 2 | a synonym for TypeWriter. |
QFont::OldEnglish | 3 | the font matcher prefers decorative fonts. |
QFont::Decorative | OldEnglish | is a synonym for OldEnglish. |
QFont::Monospace | 7 | the font matcher prefers fonts that map to the CSS generic font-family 'monospace'. |
QFont::Fantasy | 8 | the font matcher prefers fonts that map to the CSS generic font-family 'fantasy'. |
QFont::Cursive | 6 | the font matcher prefers fonts that map to the CSS generic font-family 'cursive'. |
QFont::System | 4 | the font matcher prefers system fonts. |
enum QFont::StyleStrategy
The style strategy tells the font matching algorithm what type of fonts should be used to find an appropriate default family.
The following strategies are available:
| Constant | Value | Description |
|---|---|---|
QFont::PreferDefault | 0x0001 | the default style strategy. It does not prefer any type of font. |
QFont::PreferBitmap | 0x0002 | prefers bitmap fonts (as opposed to outline fonts). |
QFont::PreferDevice | 0x0004 | prefers device fonts. |
QFont::PreferOutline | 0x0008 | prefers outline fonts (as opposed to bitmap fonts). |
QFont::ForceOutline | 0x0010 | forces the use of outline fonts. |
QFont::NoAntialias | 0x0100 | don't antialias the fonts. |
QFont::NoSubpixelAntialias | 0x0800 | avoid subpixel antialiasing on the fonts if possible. |
QFont::PreferAntialias | 0x0080 | antialias if possible. |
QFont::NoFontMerging | 0x8000 | If the font selected for a certain writing system does not contain a character requested to draw, then Qt automatically chooses a similar looking font that contains the character. The NoFontMerging flag disables this feature. Please note that enabling this flag will not prevent Qt from automatically picking a suitable font when the selected font does not support the writing system of the text. |
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). |
Any of these may be OR-ed with one of these flags:
| Constant | Value | Description |
|---|---|---|
QFont::PreferMatch | 0x0020 | prefer an exact match. The font matcher will try to use the exact font size that has been specified. |
QFont::PreferQuality | 0x0040 | prefer the best quality font. The font matcher will use the nearest standard point size that the font supports. |
enum QFont::Weight
Qt uses a weighting scale from 1 to 1000 compatible with OpenType. A weight of 1 will be thin, whilst 1000 will be extremely black.
This enum contains the predefined font weights:
| Constant | Value | Description |
|---|---|---|
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 |
Member Function Documentation
QFont::QFont()
Constructs a font object that uses the application's default font.
See also QGuiApplication::setFont() and QGuiApplication::font().
QFont::QFont(const QString &family, int pointSize = -1, int weight = -1, bool italic = false)
Constructs a font object with the specified family, pointSize, weight and italic settings.
If pointSize is zero or negative, the point size of the font is set to a system-dependent default value. Generally, this is 12 points.
The family name 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 font matching algorithm.
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.
See also Weight, setFamily(), setPointSize(), setWeight(), setItalic(), setStyleHint(), setFamilies(), and QGuiApplication::font().
[explicit] QFont::QFont(const QStringList &families, int pointSize = -1, int weight = -1, bool italic = false)
Constructs a font object with the specified families, pointSize, weight and italic settings.
If pointSize is zero or negative, the point size of the font is set to a system-dependent default value. Generally, this is 12 points.
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 font matching algorithm.
See also Weight, setPointSize(), setWeight(), setItalic(), setStyleHint(), setFamilies(), and QGuiApplication::font().
QFont::QFont(const QFont &font, const QPaintDevice *pd)
Constructs a font from font for use on the paint device pd.
QFont::QFont(const QFont &font)
Constructs a font that is a copy of font.
[noexcept] QFont::~QFont()
Destroys the font object and frees all allocated resources.
bool QFont::bold() const
Returns true if weight() is a value greater than QFont::Medium; otherwise returns false.
See also weight(), setBold(), and QFontInfo::bold().
QFont::Capitalization QFont::capitalization() const
Returns the current capitalization type of the font.
See also setCapitalization().
[since 6.7] void QFont::clearFeatures()
Clears any previously set features on the QFont.
See setFeature() for more details on font features.
This function was introduced in Qt 6.7.
See also QFont::Tag, setFeature(), unsetFeature(), featureTags(), and featureValue().
[since 6.7] void QFont::clearVariableAxes()
Clears any previously set variable axis values on the QFont.
See setVariableAxis() for more details on variable axes.
This function was introduced in Qt 6.7.
See also QFont::Tag, setVariableAxis(), unsetVariableAxis(), isVariableAxisSet(), and variableAxisValue().
QString QFont::defaultFamily() const
Returns the family name that corresponds to the current style hint.
See also StyleHint, styleHint(), and setStyleHint().
bool QFont::exactMatch() const
Returns true if a window system font exactly matching the settings of this font is available.
See also 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.
See also setFamily(), setFamilies(), family(), substitutes(), and substitute().
QString QFont::family() const
Returns the requested font family name. This will always be the same as the first entry in the families() call.
See also setFamily(), substitutes(), substitute(), setFamilies(), and families().
[since 6.7] QList<QFont::Tag> QFont::featureTags() const
Returns a list of tags for all font features currently set on this QFont.
See setFeature() for more details on font features.
This function was introduced in Qt 6.7.
See also QFont::Tag, setFeature(), unsetFeature(), isFeatureSet(), and 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.
See setFeature() for more details on font features.
This function was introduced in Qt 6.7.
See also QFont::Tag, setFeature(), unsetFeature(), featureTags(), and isFeatureSet().
bool QFont::fixedPitch() const
Returns true if fixed pitch has been set; otherwise returns false.
See also setFixedPitch() and QFontInfo::fixedPitch().
bool QFont::fromString(const QString &descrip)
Sets this font to match the description descrip. The description is a comma-separated list of the font attributes, as returned by toString().
See also toString().
QFont::HintingPreference QFont::hintingPreference() const
Returns the currently preferred hinting level for glyphs rendered with this font.
See also setHintingPreference().
[static] void QFont::insertSubstitution(const QString &familyName, const QString &substituteName)
Inserts substituteName into the substitution table for the family familyName.
After substituting a font, trigger the updating of the font by destroying and re-creating all QFont objects.
See also insertSubstitutions(), removeSubstitutions(), substitutions(), substitute(), and 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 objects.
See also insertSubstitution(), removeSubstitutions(), substitutions(), and substitute().
bool QFont::isCopyOf(const QFont &f) const
Returns 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.
See also operator=() and 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, otherwise returns false.
See setFeature() for more details on font features.
This function was introduced in Qt 6.7.
See also QFont::Tag, setFeature(), unsetFeature(), featureTags(), and 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, otherwise returns false.
See setVariableAxis() for more details on font variable axes.
This function was introduced in Qt 6.7.
See also QFont::Tag, setVariableAxis(), unsetVariableAxis(), variableAxisValue(), and clearVariableAxes().
bool QFont::italic() const
Returns true if the style() of the font is not QFont::StyleNormal
See also setItalic() and style().
bool QFont::kerning() const
Returns true if kerning should be used when drawing text with this font.
See also 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.
See also QMap.
qreal QFont::letterSpacing() const
Returns the letter spacing for the font.
See also setLetterSpacing(), letterSpacingType(), and setWordSpacing().
QFont::SpacingType QFont::letterSpacingType() const
Returns the spacing type used for letter spacing.
See also letterSpacing(), setLetterSpacing(), and setWordSpacing().
bool QFont::overline() const
Returns true if overline has been set; otherwise returns false.
See also setOverline().
int QFont::pixelSize() const
Returns the pixel size of the font if it was set with setPixelSize(). Returns -1 if the size was set with setPointSize() or setPointSizeF().
See also setPixelSize(), pointSize(), QFontInfo::pointSize(), and QFontInfo::pixelSize().
int QFont::pointSize() const
Returns the point size of the font. Returns -1 if the font size was specified in pixels.
See also setPointSize() and pointSizeF().
qreal QFont::pointSizeF() const
Returns the point size of the font. Returns -1 if the font size was specified in pixels.
See also pointSize(), setPointSizeF(), pixelSize(), QFontInfo::pointSize(), and QFontInfo::pixelSize().
[static] void QFont::removeSubstitutions(const QString &familyName)
Removes all the substitutions for familyName.
See also insertSubstitutions(), insertSubstitution(), substitutions(), and substitute().
QFont QFont::resolve(const QFont &other) const
Returns a new QFont that has attributes copied from other that have not been previously set on this font.
void QFont::setBold(bool enable)
If enable is true sets the font's weight to QFont::Bold; otherwise sets the weight to QFont::Normal.
For finer boldness control use setWeight().
Note: If styleName() is set, this value may be ignored, or if supported on the platform, the font artificially embolded.
See also bold() and setWeight().
void QFont::setCapitalization(QFont::Capitalization caps)
Sets the capitalization of the text in this font to caps.
A font's capitalization makes the text appear in the selected capitalization mode.
See also 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 font matching algorithm.
See also family(), families(), setFamily(), setStyleHint(), and QFontInfo.
void QFont::setFamily(const QString &family)
Sets the family name of the font. The name is case insensitive and may include a foundry name.
The family name 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 font matching algorithm.
See also family(), setStyleHint(), setFamilies(), families(), and QFontInfo.
[since 6.7] void QFont::setFeature(QFont::Tag tag, quint32 value)
This is an overloaded function.
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.
For example, the 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.
Note: 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().
This function was introduced in Qt 6.7.
See also QFont::Tag, clearFeatures(), setFeature(), unsetFeature(), and featureTags().
void QFont::setFixedPitch(bool enable)
If enable is true, sets fixed pitch on; otherwise sets fixed pitch off.
See also fixedPitch() and QFontInfo.
void QFont::setHintingPreference(QFont::HintingPreference hintingPreference)
Set the preference for the hinting level of the glyphs to 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 for more details.
The default hinting preference is QFont::PreferDefaultHinting.
See also hintingPreference().
void QFont::setItalic(bool enable)
Sets the style() of the font to QFont::StyleItalic if enable is true; otherwise the style is set to QFont::StyleNormal.
Note: If styleName() is set, this value may be ignored, or if supported on the platform, the font may be rendered tilted instead of picking a designed italic font-variant.
See also italic() and QFontInfo.
void QFont::setKerning(bool enable)
Enables kerning for this font if enable is true; otherwise disables it. By default, kerning is enabled.
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.
See also kerning() and 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.
See also letterSpacing(), letterSpacingType(), and setWordSpacing().
void QFont::setOverline(bool enable)
If enable is true, sets overline on; otherwise sets overline off.
See also overline() and QFontInfo.
void QFont::setPixelSize(int pixelSize)
Sets the font size to pixelSize pixels, with a maxiumum size of an unsigned 16-bit integer.
Using this function makes the font device dependent. Use setPointSize() or setPointSizeF() to set the size of the font in a device independent manner.
See also pixelSize().
void QFont::setPointSize(int pointSize)
Sets the point size to pointSize. The point size must be greater than zero.
See also pointSize() and setPointSizeF().
void QFont::setPointSizeF(qreal pointSize)
Sets the point size to pointSize. The point size must be greater than zero. The requested precision may not be achieved on all platforms.
See also pointSizeF(), setPointSize(), and setPixelSize().
void QFont::setStretch(int factor)
Sets the stretch factor for the font.
The stretch factor matches a condensed or expanded version of the font or applies a stretch transform that changes the width of all characters in the font by factor percent. For example, setting factor to 150 results in all characters in the font being 1.5 times (ie. 150%) wider. The minimum stretch factor is 1, and the maximum stretch factor is 4000. The default stretch factor is AnyStretch, which will accept any stretch factor and not apply any transform on the font.
The stretch factor is only applied to outline fonts. The stretch factor is ignored for bitmap fonts.
Note: When matching a font with a native non-default stretch factor, requesting a stretch of 100 will stretch it back to a medium width font.
See also stretch() and QFont::Stretch.
void QFont::setStrikeOut(bool enable)
If enable is true, sets strikeout on; otherwise sets strikeout off.
See also strikeOut() and QFontInfo.
void QFont::setStyle(QFont::Style style)
Sets the style of the font to style.
See also style(), italic(), and QFontInfo.
void QFont::setStyleHint(QFont::StyleHint hint, QFont::StyleStrategy strategy = PreferDefault)
Sets the style hint and strategy to hint and strategy, respectively.
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.
See also StyleHint, styleHint(), StyleStrategy, styleStrategy(), and QFontInfo.
void QFont::setStyleName(const QString &styleName)
Sets the style name of the font to styleName. When set, other style properties like style() and 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
See also styleName().
void QFont::setStyleStrategy(QFont::StyleStrategy s)
Sets the style strategy for the font to s.
See also styleStrategy() and QFont::StyleStrategy.
void QFont::setUnderline(bool enable)
If enable is true, sets underline on; otherwise sets underline off.
See also underline() and 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.
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.
Note: 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.
This function was introduced in Qt 6.7.
See also unsetVariableAxis.
void QFont::setWeight(QFont::Weight weight)
Sets the weight of the font to weight, using the scale defined by QFont::Weight enumeration.
Note: If styleName() is set, this value may be ignored for font selection.
See also weight() and QFontInfo.
void QFont::setWordSpacing(qreal spacing)
Sets the word spacing for the font to spacing.
Word spacing changes the default spacing between individual words. A positive value increases the word spacing by a corresponding amount of pixels, while a negative value decreases the inter-word spacing accordingly.
Word spacing will not apply to writing systems, where indiviaul words are not separated by white space.
See also wordSpacing() and setLetterSpacing().
int QFont::stretch() const
Returns the stretch factor for the font.
See also setStretch().
bool QFont::strikeOut() const
Returns true if strikeout has been set; otherwise returns false.
See also setStrikeOut().
QFont::Style QFont::style() const
Returns the style of the font.
See also setStyle().
QFont::StyleHint QFont::styleHint() const
Returns the StyleHint.
The style hint affects the font matching algorithm. See QFont::StyleHint for the list of available hints.
See also setStyleHint(), QFont::StyleStrategy, and QFontInfo::styleHint().
QString QFont::styleName() const
Returns the requested font style name. This can be used to match the font with irregular styles (that can't be normalized in other style properties).
See also setStyleName(), setFamily(), and setStyle().
QFont::StyleStrategy QFont::styleStrategy() const
Returns the StyleStrategy.
The style strategy affects the font matching algorithm. See QFont::StyleStrategy for the list of available strategies.
See also setStyleStrategy(), setStyleHint(), and QFont::StyleHint.
[static] QString QFont::substitute(const QString &familyName)
Returns the first family name to be used whenever familyName is specified. The lookup is case insensitive.
If there is no substitution for familyName, familyName is returned.
To obtain a list of substitutions use substitutes().
See also setFamily(), insertSubstitutions(), insertSubstitution(), and removeSubstitutions().
[static] QStringList QFont::substitutes(const QString &familyName)
Returns a list of family names to be used whenever familyName is specified. The lookup is case insensitive.
If there is no substitution for familyName, an empty list is returned.
See also substitute(), insertSubstitutions(), insertSubstitution(), and removeSubstitutions().
[static] QStringList QFont::substitutions()
Returns a sorted list of substituted family names.
See also insertSubstitution(), removeSubstitutions(), and substitute().
[noexcept] void QFont::swap(QFont &other)
Swaps this font instance with other. This function is very fast and never fails.
QString QFont::toString() const
Returns a description of the font. The description is a comma-separated list of the attributes, perfectly suited for use in QSettings, and consists of the following:
- 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)
See also fromString().
bool QFont::underline() const
Returns true if underline has been set; otherwise returns false.
See also setUnderline().
[since 6.7] void QFont::unsetFeature(QFont::Tag tag)
This is an overloaded function.
Unsets the tag from the map of explicitly enabled/disabled features.
Note: 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.
See setFeature() for more details on font features.
This function was introduced in Qt 6.7.
See also QFont::Tag, clearFeatures(), setFeature(), featureTags(), and featureValue().
[since 6.7] void QFont::unsetVariableAxis(QFont::Tag tag)
Unsets a previously set variable axis value given by tag.
Note: 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 values.
This function was introduced in Qt 6.7.
See also setVariableAxis.
[since 6.7] QList<QFont::Tag> QFont::variableAxisTags() const
Returns a list of tags for all variable axes currently set on this QFont.
See setVariableAxis() for more details on variable axes.
This function was introduced in Qt 6.7.
See also QFont::Tag, setVariableAxis(), unsetVariableAxis(), isVariableAxisSet(), and 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.
See setVariableAxis() for more details on variable axes.
This function was introduced in Qt 6.7.
See also QFont::Tag, setVariableAxis(), unsetVariableAxis(), isVariableAxisSet(), and clearVariableAxes().
QFont::Weight QFont::weight() const
Returns the weight of the font, using the same scale as the QFont::Weight enumeration.
See also setWeight(), Weight, and QFontInfo.
qreal QFont::wordSpacing() const
Returns the word spacing for the font.
See also setWordSpacing() and setLetterSpacing().
QVariant QFont::operator QVariant() const
Returns the font as a QVariant
bool QFont::operator!=(const QFont &f) const
Returns true if this font is different from f; otherwise returns false.
Two QFonts are considered to be different if their font attributes are different.
See also operator==().
bool QFont::operator<(const QFont &f) const
Provides an arbitrary comparison of this font and font f. All that is guaranteed is that the operator returns false if both fonts are equal and that (f1 < f2) == !(f2 < f1) if the fonts are not equal.
This function is useful in some circumstances, for example if you want to use QFont objects as keys in a QMap.
See also operator==(), operator!=(), and isCopyOf().
QFont &QFont::operator=(const QFont &font)
Assigns font to this font and returns a reference to it.
[noexcept] QFont &QFont::operator=(QFont &&other)
Move-assigns other to this QFont instance.
bool QFont::operator==(const QFont &f) const
Returns true if this font is equal to f; otherwise returns false.
Two QFonts are considered equal if their font attributes are equal.
See also operator!=() and isCopyOf().
Related Non-Members
[noexcept] size_t qHash(const QFont &font, size_t seed = 0)
Returns the hash value for font. If specified, seed is used to initialize the hash.
QDataStream &operator<<(QDataStream &s, const QFont &font)
Writes the font font to the data stream s. (toString() writes to a text stream.)
See also Format of the QDataStream operators.
QDataStream &operator>>(QDataStream &s, QFont &font)
Reads the font font from the data stream s. (fromString() reads from a text stream.)
See also Format of the QDataStream operators.
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