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 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.

See also Weight, setFamily(), setPointSize(), setWeight(), setItalic(), setStyleHint(), and QGuiApplication::font().

QFont::QFont(const QFont &font, 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.

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.

This function was introduced in Qt 4.4.

See also setCapitalization().

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.

QString QFont::family() const

Returns the requested font family name, i.e. the name set in the constructor or the last setFont() call.

See also setFamily(), substitutes(), and substitute().

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.

This function was introduced in Qt 4.8.

See also setHintingPreference().

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

Inserts substituteName into the substitution table for the family familyName.

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.

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==().

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.

QString QFont::lastResortFamily() const

Returns the "last resort" font family name.

The current implementation tries a wide variety of common fonts, returning the first one it finds. Is is possible that no family is found in which case an empty string is returned.

See also lastResortFont().

QString QFont::lastResortFont() const

Returns a "last resort" font name for the font matching algorithm. This is used if the last resort family is not available. It will always return a name, if necessary returning something like "fixed" or "system".

The current implementation tries a wide variety of common fonts, returning the first one it finds. The implementation may change at any time, but this function will always return a string containing something.

It is theoretically possible that there really isn't a lastResortFont() in which case Qt will abort with an error message. We have not been able to identify a case where this happens. Please report it as a bug if it does, preferably with a list of the fonts you have installed.

See also lastResortFamily().

qreal QFont::letterSpacing() const

Returns the letter spacing for the font.

This function was introduced in Qt 4.4.

See also setLetterSpacing(), letterSpacingType(), and setWordSpacing().

QFont::SpacingType QFont::letterSpacingType() const

Returns the spacing type used for letter spacing.

This function was introduced in Qt 4.4.

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.

This function was introduced in Qt 5.0.

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.

This function was introduced in Qt 4.4.

See also capitalization().

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(), and QFontInfo.

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.

This function was introduced in Qt 4.8.

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.

This function was introduced in Qt 4.4.

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.

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

This function was introduced in Qt 4.8.

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.

void QFont::setWeight(int 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.

This function was introduced in Qt 4.4.

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).

This function was introduced in Qt 4.8.

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(), removeSubstitution(), and substitute().

void QFont::swap(QFont &other)

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

This function was introduced in Qt 5.0.

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.

See also fromString().

bool QFont::underline() const

Returns true if underline has been set; otherwise returns false.

See also setUnderline().

int 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.

This function was introduced in Qt 4.4.

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.

QFont &QFont::operator=(QFont &&other)

Move-assigns other to this QFont instance.

This function was introduced in Qt 5.2.

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().