QFont Class

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

 QFont f("Helvetica");

 QFont f("Helvetica [Cronyx]");

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

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

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 QFont &font, const QPaintDevice *pd)

Constructs a font from font for use on the paint device pd.

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)

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().

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.

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.

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.

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.

 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.

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.

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.

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.

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().

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

Move-assigns other to this QFont instance.

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

Assigns font to this font and returns a reference to it.

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().