\reentrant \inmodule QtGui More...

#include <qfontmetrics.h>

Collaboration diagram for QFontMetrics:

Public Member Functions
	QFontMetrics (const QFont &)
	Constructs a font metrics object for font.

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

	QFontMetrics (const QFontMetrics &)
	Constructs a copy of fm.

	~QFontMetrics ()
	Destroys the font metrics object and frees all allocated resources.

QFontMetrics &	operator= (const QFontMetrics &)
	Assigns the font metrics fm.

void	swap (QFontMetrics &other) noexcept

int	ascent () const
	Returns the ascent of the font.

int	capHeight () const
	Returns the cap height of the font.

int	descent () const
	Returns the descent of the font.

int	height () const
	Returns the height of the font.

int	leading () const
	Returns the leading of the font.

int	lineSpacing () const
	Returns the distance from one base line to the next.

int	minLeftBearing () const
	Returns the minimum left bearing of the font.

int	minRightBearing () const
	Returns the minimum right bearing of the font.

int	maxWidth () const
	Returns the width of the widest character in the font.

int	xHeight () const
	Returns the 'x' height of the font.

int	averageCharWidth () const

bool	inFont (QChar) const
	Returns `true` if character ch is a valid character in the font; otherwise returns `false`.

bool	inFontUcs4 (uint ucs4) const
	Returns `true` if the character ucs4 encoded in UCS-4/UTF-32 is a valid character in the font; otherwise returns `false`.

int	leftBearing (QChar) const
	Returns the left bearing of character ch in the font.

int	rightBearing (QChar) const
	Returns the right bearing of character ch in the font.

int	horizontalAdvance (const QString &, int len=-1) const
	Returns the horizontal advance in pixels of the first len characters of text.

int	horizontalAdvance (const QString &, const QTextOption &textOption) const
	Returns the horizontal advance in pixels of text laid out using option.

int	horizontalAdvance (QChar) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

QRect	boundingRect (QChar) const
	Returns the rectangle that is covered by ink if character ch were to be drawn at the origin of the coordinate system.

QRect	boundingRect (const QString &text) const
	Returns the bounding rectangle of the characters in the string specified by text.

QRect	boundingRect (const QString &text, const QTextOption &textOption) const
	Returns the bounding rectangle of the characters in the string specified by text laid out using option.

QRect	boundingRect (const QRect &r, int flags, const QString &text, int tabstops=0, int *tabarray=nullptr) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Returns the bounding rectangle of the characters in the string specified by text, which is the set of pixels the text would cover if drawn at (0, 0).

QRect	boundingRect (int x, int y, int w, int h, int flags, const QString &text, int tabstops=0, int *tabarray=nullptr) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Returns the bounding rectangle for the given text within the rectangle specified by the x and y coordinates, width, and height.

QSize	size (int flags, const QString &str, int tabstops=0, int *tabarray=nullptr) const
	Returns the size in pixels of text.

QRect	tightBoundingRect (const QString &text) const
	Returns a tight bounding rectangle around the characters in the string specified by text.

QRect	tightBoundingRect (const QString &text, const QTextOption &textOption) const
	Returns a tight bounding rectangle around the characters in the string specified by text laid out using option.

QString	elidedText (const QString &text, Qt::TextElideMode mode, int width, int flags=0) const

int	underlinePos () const
	Returns the distance from the base line to where an underscore should be drawn.

int	overlinePos () const
	Returns the distance from the base line to where an overline should be drawn.

int	strikeOutPos () const
	Returns the distance from the base line to where the strikeout line should be drawn.

int	lineWidth () const
	Returns the width of the underline and strikeout lines, adjusted for the point size of the font.

qreal	fontDpi () const

bool	operator== (const QFontMetrics &other) const
	Returns `true` if other is equal to this object; otherwise returns `false`.

bool	operator!= (const QFontMetrics &other) const
	Returns `true` if other is not equal to this object; otherwise returns `false`.

Friends
class	QFontMetricsF

class	QStackTextEngine

Detailed Description

\reentrant \inmodule QtGui

The QFontMetrics class provides font metrics information.

QFontMetrics functions calculate the size of characters and strings for a given font. There are three ways you can create a QFontMetrics object:

\list 1

Calling the QFontMetrics constructor with a QFont creates a font metrics object for a screen-compatible font, i.e. the font cannot be a printer font. If the font is changed later, the font metrics object is not updated.

(Note: If you use a printer font the values returned may be inaccurate. Printer fonts are not always accessible so the nearest screen font is used if a printer font is supplied.)

QWidget::fontMetrics() returns the font metrics for a widget's font. This is equivalent to QFontMetrics(widget->font()). If the widget's font is changed later, the font metrics object is not updated.

QPainter::fontMetrics() returns the font metrics for a painter's current font. If the painter's font is changed later, the font metrics object is not updated. \endlist

Once created, the object provides functions to access the individual metrics of the font, its characters, and for strings rendered in the font.

There are several functions that operate on the font: ascent(), descent(), height(), leading() and lineSpacing() return the basic size properties of the font. The underlinePos(), overlinePos(), strikeOutPos() and lineWidth() functions, return the properties of the line that underlines, overlines or strikes out the characters. These functions are all fast.

There are also some functions that operate on the set of glyphs in the font: minLeftBearing(), minRightBearing() and maxWidth(). These are by necessity slow, and we recommend avoiding them if possible.

For each character, you can get its horizontalAdvance(), leftBearing(), and rightBearing(), and find out whether it is in the font using inFont(). You can also treat the character as a string, and use the string functions on it.

The string functions include horizontalAdvance(), to return the advance width of a string in pixels (or points, for a printer), boundingRect(), to return a rectangle large enough to contain the rendered string, and size(), to return the size of that rectangle.

Note: The advance width can be different from the width of the actual rendered text. It refers to the distance from the origin of the string to where you would append additional characters. As text may have overhang (in the case of an italic font for instance) or padding between characters, the advance width can be either smaller or larger than the actual rendering of the text. This is called the right bearing of the text.

Example:

QFont font("times", 24);
QFontMetrics fm(font);
int pixelsWide = fm.horizontalAdvance("What's the advance width of this text?");
int pixelsHigh = fm.height();

See also: QFont, QFontInfo, QFontDatabase

Definition at line 20 of file qfontmetrics.h.

Constructor & Destructor Documentation

◆ QFontMetrics() [1/3]

QFontMetrics::QFontMetrics ( const QFont & font )

explicit

Constructs a font metrics object for font.

The font metrics will be compatible with the paintdevice used to create font.

The font metrics object holds the information for the font that is passed in the constructor at the time it is created, and is not updated if the font's attributes are changed later.

Use QFontMetrics(const QFont &, QPaintDevice *) to get the font metrics that are compatible with a certain paint device.

Definition at line 125 of file qfontmetrics.cpp.

◆ QFontMetrics() [2/3]

QFontMetrics::QFontMetrics	(	const QFont &	font,
		const QPaintDevice *	paintdevice )

Since: 5.13

Constructs a font metrics object for font and paintdevice.

The font metrics will be compatible with the paintdevice passed. If the paintdevice is \nullptr, the metrics will be screen-compatible, ie. the metrics you get if you use the font for drawing text on a \l{QWidget}{widgets} or \l{QPixmap}{pixmaps}, not on a QPicture or QPrinter.

The font metrics object holds the information for the font that is passed in the constructor at the time it is created, and is not updated if the font's attributes are changed later.

Definition at line 145 of file qfontmetrics.cpp.

References QFontPrivate::dpi, font, and qt_defaultDpi().

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◆ QFontMetrics() [3/3]

QFontMetrics::QFontMetrics ( const QFontMetrics & fm )

Constructs a copy of fm.

Definition at line 160 of file qfontmetrics.cpp.

◆ ~QFontMetrics()

QFontMetrics::~QFontMetrics ( )

Destroys the font metrics object and frees all allocated resources.

Definition at line 169 of file qfontmetrics.cpp.

Member Function Documentation

◆ ascent()

int QFontMetrics::ascent ( ) const

Returns the ascent of the font.

The ascent of a font is the distance from the baseline to the highest position characters extend to. In practice, some font designers break this rule, e.g. when they put more than one accent on top of a character, or to accommodate a certain character, so it is possible (though rare) that this value will be too small.

See also: descent()

Definition at line 241 of file qfontmetrics.cpp.

References engine, QFontPrivate::engineForScript(), Q_ASSERT, and qRound().

Referenced by overlinePos(), QTextDocument::print(), and strikeOutPos().

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◆ averageCharWidth()

int QFontMetrics::averageCharWidth ( ) const

Since: 4.2

Returns the average width of glyphs in the font.

Definition at line 388 of file qfontmetrics.cpp.

References engine, QFontPrivate::engineForScript(), Q_ASSERT, and qRound().

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◆ boundingRect() [1/5]

QRect QFontMetrics::boundingRect	(	const QRect &	rect,
		int	flags,
		const QString &	text,
		int	tabStops = 0,
		int *	tabArray = nullptr ) const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Returns the bounding rectangle of the characters in the string specified by text, which is the set of pixels the text would cover if drawn at (0, 0).

The drawing, and hence the bounding rectangle, is constrained to the rectangle rect.

The flags argument is the bitwise OR of the following flags: \list

Qt::AlignLeft aligns to the left border, except for Arabic and Hebrew where it aligns to the right.
Qt::AlignRight aligns to the right border, except for Arabic and Hebrew where it aligns to the left.
Qt::AlignJustify produces justified text.
Qt::AlignHCenter aligns horizontally centered.
Qt::AlignTop aligns to the top border.
Qt::AlignBottom aligns to the bottom border.
Qt::AlignVCenter aligns vertically centered
Qt::AlignCenter (== {Qt::AlignHCenter | Qt::AlignVCenter})
Qt::TextSingleLine ignores newline characters in the text.
Qt::TextExpandTabs expands tabs (see below)
Qt::TextShowMnemonic interprets "&x" as \underline{x}; i.e., underlined.
Qt::TextWordWrap breaks the text to fit the rectangle. \endlist

Qt::Horizontal alignment defaults to Qt::AlignLeft and vertical alignment defaults to Qt::AlignTop.

If several of the horizontal or several of the vertical alignment flags are set, the resulting alignment is undefined.

If Qt::TextExpandTabs is set in flags, then: if tabArray is non-null, it specifies a 0-terminated sequence of pixel-positions for tabs; otherwise if tabStops is non-zero, it is used as the tab spacing (in pixels).

Note that the bounding rectangle may extend to the left of (0, 0), e.g. for italicized fonts, and that the text output may cover all pixels in the bounding rectangle.

Newline characters are processed as linebreaks.

Despite the different actual character heights, the heights of the bounding rectangles of "Yes" and "yes" are the same.

The bounding rectangle returned by this function is somewhat larger than that calculated by the simpler boundingRect() function. This function uses the \l{minLeftBearing()}{maximum left} and \l{minRightBearing()}{right} font bearings as is necessary for multi-line text to align correctly. Also, fontHeight() and lineSpacing() are used to calculate the height, rather than individual character heights.

See also: horizontalAdvance(), QPainter::boundingRect(), Qt::Alignment

Definition at line 756 of file qfontmetrics.cpp.

References QExplicitlySharedDataPointer< T >::data(), qt_format_text(), rect, text, Qt::TextDontPrint, and QRectF::toAlignedRect().

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◆ boundingRect() [2/5]

QRect QFontMetrics::boundingRect ( const QString & text ) const

Returns the bounding rectangle of the characters in the string specified by text.

The bounding rectangle always covers at least the set of pixels the text would cover if drawn at (0, 0).

Note that the bounding rectangle may extend to the left of (0, 0), e.g. for italicized fonts, and that the width of the returned rectangle might be different than what the horizontalAdvance() method returns.

If you want to know the advance width of the string (to lay out a set of strings next to each other), use horizontalAdvance() instead.

Newline characters are processed as normal characters, not as linebreaks.

The height of the bounding rectangle is at least as large as the value returned by height().

See also: horizontalAdvance(), height(), QPainter::boundingRect(), tightBoundingRect()

Definition at line 618 of file qfontmetrics.cpp.

References QExplicitlySharedDataPointer< T >::data(), layout, qRound(), QString::size(), and text.

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◆ boundingRect() [3/5]

QRect QFontMetrics::boundingRect	(	const QString &	text,
		const QTextOption &	option ) const

Returns the bounding rectangle of the characters in the string specified by text laid out using option.

The bounding rectangle always covers at least the set of pixels the text would cover if drawn at (0, 0).

Note that the bounding rectangle may extend to the left of (0, 0), e.g. for italicized fonts, and that the width of the returned rectangle might be different than what the horizontalAdvance() method returns.

If you want to know the advance width of the string (to lay out a set of strings next to each other), use horizontalAdvance() instead.

Newline characters are processed as normal characters, not as linebreaks.

The height of the bounding rectangle is at least as large as the value returned by height().

Since: 6.3

See also: horizontalAdvance(), height(), QPainter::boundingRect(), tightBoundingRect()

Definition at line 653 of file qfontmetrics.cpp.

References QExplicitlySharedDataPointer< T >::data(), layout, qRound(), QString::size(), and text.

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◆ boundingRect() [4/5]

QRect QFontMetrics::boundingRect	(	int	x,
		int	y,
		int	width,
		int	height,
		int	flags,
		const QString &	text,
		int	tabStops = 0,
		int *	tabArray = nullptr ) const

inline

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Returns the bounding rectangle for the given text within the rectangle specified by the x and y coordinates, width, and height.

If Qt::TextExpandTabs is set in flags and tabArray is non-null, it specifies a 0-terminated sequence of pixel-positions for tabs; otherwise, if tabStops is non-zero, it is used as the tab spacing (in pixels).

Definition at line 62 of file qfontmetrics.h.

References boundingRect(), and text.

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◆ boundingRect() [5/5]

QRect QFontMetrics::boundingRect ( QChar ch ) const

Returns the rectangle that is covered by ink if character ch were to be drawn at the origin of the coordinate system.

Note that the bounding rectangle may extend to the left of (0, 0) (e.g., for italicized fonts), and that the text output may cover all pixels in the bounding rectangle. For a space character the rectangle will usually be empty.

Note that the rectangle usually extends both above and below the base line.

Warning: The width of the returned rectangle is not the advance width of the character. Use boundingRect(const QString &) or horizontalAdvance() instead.

See also: horizontalAdvance()

Definition at line 682 of file qfontmetrics.cpp.

References QFontPrivate::alterCharForCapitalization(), QFontPrivate::capital, ch, engine, QFontPrivate::engineForScript(), Q_ASSERT, qRound(), QFont::SmallCaps, and QFontPrivate::smallCapsFontPrivate().

Referenced by QWhatsThat::QWhatsThat(), QQC2::QCommonStyle::drawControl(), QCommonStyle::drawControl(), QWindows11Style::drawControl(), QGeoTiledMapNokia::evaluateCopyrights(), size(), QAndroidStyle::sizeFromContents(), QAndroidStyle::subControlRect(), and QQC2::QMacStylePrivate::tabLayout().

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◆ capHeight()

int QFontMetrics::capHeight ( ) const

Returns the cap height of the font.

Since: 5.8

The cap height of a font is the height of a capital letter above the baseline. It specifically is the height of capital letters that are flat - such as H or I - as opposed to round letters such as O, or pointed letters like A, both of which may display overshoot.

See also: ascent()

Definition at line 260 of file qfontmetrics.cpp.

References engine, QFontPrivate::engineForScript(), Q_ASSERT, and qRound().

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◆ descent()

int QFontMetrics::descent ( ) const

Returns the descent of the font.

The descent is the distance from the base line to the lowest point characters extend to. In practice, some font designers break this rule, e.g. to accommodate a certain character, so it is possible (though rare) that this value will be too small.

See also: ascent()

Definition at line 277 of file qfontmetrics.cpp.

References engine, QFontPrivate::engineForScript(), Q_ASSERT, and qRound().

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◆ elidedText()

QString QFontMetrics::elidedText	(	const QString &	text,
		Qt::TextElideMode	mode,
		int	width,
		int	flags = 0 ) const

Since: 4.2

If the string text is wider than width, returns an elided version of the string (i.e., a string with "..." in it). Otherwise, returns the original string.

The mode parameter specifies whether the text is elided on the left (e.g., "...tech"), in the middle (e.g., "Tr...ch"), or on the right (e.g., "Trol...").

The width is specified in pixels, not characters.

The flags argument is optional and currently only supports Qt::TextShowMnemonic as value.

The elide mark follows the \l{Qt::LayoutDirection}{layoutdirection}. For example, it will be on the right side of the text for right-to-left layouts if the mode is {Qt::ElideLeft}, and on the left side of the text if the mode is {Qt::ElideRight}.

Definition at line 887 of file qfontmetrics.cpp.

References QExplicitlySharedDataPointer< T >::data(), engine, QString::indexOf(), QString::mid(), s_variableLengthStringSeparator(), text, and Qt::TextLongestVariant.

Referenced by QWindows11Style::drawComplexControl(), QWindowsVistaStyle::drawControl(), QTabBar::initStyleOption(), QGraphicsWidgetPrivate::initStyleOptionTitleBar(), QFileDialogComboBox::paintEvent(), and QMdiSubWindowPrivate::titleBarOptions().

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◆ fontDpi()

qreal QFontMetrics::fontDpi ( ) const

Since: 5.14

Returns the font DPI.

Definition at line 960 of file qfontmetrics.cpp.

References QFontPrivate::dpi.

◆ height()

int QFontMetrics::height ( ) const

Returns the height of the font.

This is always equal to ascent()+descent().

See also: leading(), lineSpacing()

Definition at line 291 of file qfontmetrics.cpp.

References engine, QFontPrivate::engineForScript(), Q_ASSERT, and qRound().

Referenced by QQC2_NAMESPACE::QMacStyle::drawPrimitive(), QMacStyle::drawPrimitive(), QStatusBar::event(), lengthValueFromData(), QQC2::QCommonStyle::pixelMetric(), QCommonStyle::pixelMetric(), QStatusBar::reformat(), QQuickTextEdit::setFont(), QAndroidStyle::AndroidControl::sizeFromContents(), QQC2::QCommonStyle::subControlRect(), QCommonStyle::subControlRect(), and QAndroidStyle::subControlRect().

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◆ horizontalAdvance() [1/3]

int QFontMetrics::horizontalAdvance	(	const QString &	text,
		const QTextOption &	option ) const

Returns the horizontal advance in pixels of text laid out using option.

The advance is the distance appropriate for drawing a subsequent character after text.

Since: 6.3

See also: boundingRect()

Definition at line 526 of file qfontmetrics.cpp.

References QExplicitlySharedDataPointer< T >::data(), QString::indexOf(), layout, pos, qRound(), s_variableLengthStringSeparator(), QString::size(), and text.

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◆ horizontalAdvance() [2/3]

int QFontMetrics::horizontalAdvance	(	const QString &	text,
		int	len = -1 ) const

Returns the horizontal advance in pixels of the first len characters of text.

If len is negative (the default), the entire string is used. The entire length of text is analysed even if len is substantially shorter.

This is the distance appropriate for drawing a subsequent character after text.

Since: 5.11

See also: boundingRect()

Definition at line 499 of file qfontmetrics.cpp.

References QExplicitlySharedDataPointer< T >::data(), QString::indexOf(), layout, QStringView::left(), pos, qRound(), s_variableLengthStringSeparator(), QString::size(), and text.

Referenced by QComboBoxPrivate::computeWidthHint(), QQuickTextInput::cursorRectangle(), QFontFamilyDelegate::paint(), QQuickTextInput::positionToRectangle(), printPage(), QWidgetTextControlPrivate::rectForPosition(), and QQuickTextControlPrivate::rectForPosition().

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◆ horizontalAdvance() [3/3]

int QFontMetrics::horizontalAdvance ( QChar ch ) const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Bearings

Returns the horizontal advance of character ch in pixels. This is a distance appropriate for drawing a subsequent character after ch.

Some of the metrics are described in the image. The central dark rectangles cover the logical horizontalAdvance() of each character. The outer pale rectangles cover the leftBearing() and rightBearing() of each character. Notice that the bearings of "f" in this particular font are both negative, while the bearings of "o" are both positive.

Warning: This function will produce incorrect results for Arabic characters or non-spacing marks in the middle of a string, as the glyph shaping and positioning of marks that happens when processing strings cannot be taken into account. When implementing an interactive text control, use QTextLayout instead.

Since: 5.11

See also: boundingRect()

Definition at line 569 of file qfontmetrics.cpp.

References QGlyphLayout::advances, QFontPrivate::alterCharForCapitalization(), QFontPrivate::capital, ch, engine, QFontPrivate::engineForScript(), QGlyphLayout::glyphs, QGlyphLayout::numGlyphs, Q_ASSERT, qRound(), QFont::SmallCaps, and QFontPrivate::smallCapsFontPrivate().

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◆ inFont()

bool QFontMetrics::inFont ( QChar ch ) const

Returns true if character ch is a valid character in the font; otherwise returns false.

Definition at line 399 of file qfontmetrics.cpp.

References ch, and inFontUcs4().

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◆ inFontUcs4()

bool QFontMetrics::inFontUcs4 ( uint ucs4 ) const

Returns true if the character ucs4 encoded in UCS-4/UTF-32 is a valid character in the font; otherwise returns false.

Definition at line 408 of file qfontmetrics.cpp.

References QFontEngine::Box, engine, QFontPrivate::engineForScript(), and Q_ASSERT.

Referenced by inFont().

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◆ leading()

int QFontMetrics::leading ( ) const

Returns the leading of the font.

This is the natural inter-line spacing.

See also: height(), lineSpacing()

Definition at line 305 of file qfontmetrics.cpp.

References engine, QFontPrivate::engineForScript(), Q_ASSERT, and qRound().

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◆ leftBearing()

int QFontMetrics::leftBearing ( QChar ch ) const

Returns the left bearing of character ch in the font.

The left bearing is the right-ward distance of the left-most pixel of the character from the logical origin of the character. This value is negative if the pixels of the character extend to the left of the logical origin.

See horizontalAdvance() for a graphical description of this metric.

See also: rightBearing(), minLeftBearing(), horizontalAdvance()

Definition at line 430 of file qfontmetrics.cpp.

References QFontPrivate::alterCharForCapitalization(), QFontEngine::Box, QFontPrivate::capital, ch, engine, QFontPrivate::engineForScript(), Q_ASSERT, qRound(), QFont::SmallCaps, and QFontPrivate::smallCapsFontPrivate().

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◆ lineSpacing()

int QFontMetrics::lineSpacing ( ) const

Returns the distance from one base line to the next.

This value is always equal to leading()+height().

See also: height(), leading()

Definition at line 319 of file qfontmetrics.cpp.

References engine, QFontPrivate::engineForScript(), Q_ASSERT, and qRound().

Referenced by src_gui_text_qtextlayout::Wrapper::elided().

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◆ lineWidth()

int QFontMetrics::lineWidth ( ) const

Returns the width of the underline and strikeout lines, adjusted for the point size of the font.

See also: underlinePos(), overlinePos(), strikeOutPos()

Definition at line 948 of file qfontmetrics.cpp.

References engine, QFontPrivate::engineForScript(), Q_ASSERT, and qRound().

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◆ maxWidth()

int QFontMetrics::maxWidth ( ) const

Returns the width of the widest character in the font.

Definition at line 363 of file qfontmetrics.cpp.

References engine, QFontPrivate::engineForScript(), Q_ASSERT, and qRound().

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◆ minLeftBearing()

int QFontMetrics::minLeftBearing ( ) const

Returns the minimum left bearing of the font.

This is the smallest leftBearing(char) of all characters in the font.

Note that this function can be very slow if the font is large.

See also: minRightBearing(), leftBearing()

Definition at line 336 of file qfontmetrics.cpp.

References engine, QFontPrivate::engineForScript(), Q_ASSERT, and qRound().

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◆ minRightBearing()

int QFontMetrics::minRightBearing ( ) const

Returns the minimum right bearing of the font.

This is the smallest rightBearing(char) of all characters in the font.

Note that this function can be very slow if the font is large.

See also: minLeftBearing(), rightBearing()

Definition at line 353 of file qfontmetrics.cpp.

References engine, QFontPrivate::engineForScript(), Q_ASSERT, and qRound().

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◆ operator!=()

bool QFontMetrics::operator!= ( const QFontMetrics & other ) const

inline

Returns true if other is not equal to this object; otherwise returns false.

Two font metrics are considered equal if they were constructed from the same QFont and the paint devices they were constructed for are considered compatible.

See also: operator==()

Definition at line 80 of file qfontmetrics.h.

References operator==(), and other().

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◆ operator=()

QFontMetrics & QFontMetrics::operator= ( const QFontMetrics & fm )

Assigns the font metrics fm.

Move-assigns other to this QFontMetrics instance.

Since: 5.2

Definition at line 176 of file qfontmetrics.cpp.

◆ operator==()

bool QFontMetrics::operator== ( const QFontMetrics & other ) const

Returns true if other is equal to this object; otherwise returns false.

Two font metrics are considered equal if they were constructed from the same QFont and the paint devices they were constructed for are considered compatible.

See also: operator!=()

Definition at line 213 of file qfontmetrics.cpp.

References other().

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◆ overlinePos()

int QFontMetrics::overlinePos ( ) const

Returns the distance from the base line to where an overline should be drawn.

See also: underlinePos(), strikeOutPos(), lineWidth()

Definition at line 925 of file qfontmetrics.cpp.

References ascent().

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◆ rightBearing()

int QFontMetrics::rightBearing ( QChar ch ) const

Returns the right bearing of character ch in the font.

The right bearing is the left-ward distance of the right-most pixel of the character from the logical origin of a subsequent character. This value is negative if the pixels of the character extend to the right of the horizontalAdvance() of the character.

See horizontalAdvance() for a graphical description of this metric.

See also: leftBearing(), minRightBearing(), horizontalAdvance()

Definition at line 463 of file qfontmetrics.cpp.

References QFontPrivate::alterCharForCapitalization(), QFontEngine::Box, QFontPrivate::capital, ch, engine, QFontPrivate::engineForScript(), Q_ASSERT, qRound(), QFont::SmallCaps, and QFontPrivate::smallCapsFontPrivate().

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◆ size()

QSize QFontMetrics::size	(	int	flags,
		const QString &	text,
		int	tabStops = 0,
		int *	tabArray = nullptr ) const

Returns the size in pixels of text.

The flags argument is the bitwise OR of the following flags: \list

Qt::TextSingleLine ignores newline characters.
Qt::TextExpandTabs expands tabs (see below)
Qt::TextShowMnemonic interprets "&x" as \underline{x}; i.e., underlined.
Qt::TextWordWrap breaks the text to fit the rectangle. \endlist

If Qt::TextExpandTabs is set in flags, then: if tabArray is non-null, it specifies a 0-terminated sequence of pixel-positions for tabs; otherwise if tabStops is non-zero, it is used as the tab spacing (in pixels).

Newline characters are processed as linebreaks.

Despite the different actual character heights, the heights of the bounding rectangles of "Yes" and "yes" are the same.

See also: boundingRect()

Definition at line 795 of file qfontmetrics.cpp.

References boundingRect(), QRect::size(), text, and Qt::TextLongestVariant.

Referenced by QQC2_NAMESPACE::QMacStyle::sizeFromContents(), QAndroidStyle::sizeFromContents(), QMacStyle::sizeFromContents(), and QToolBoxButton::sizeHint().

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◆ strikeOutPos()

int QFontMetrics::strikeOutPos ( ) const

Returns the distance from the base line to where the strikeout line should be drawn.

See also: underlinePos(), overlinePos(), lineWidth()

Definition at line 936 of file qfontmetrics.cpp.

References ascent(), and pos.

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◆ swap()

void QFontMetrics::swap ( QFontMetrics & other )

inlinenoexcept

Since: 5.0

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

Definition at line 31 of file qfontmetrics.h.

References d, and other().

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◆ tightBoundingRect() [1/2]

QRect QFontMetrics::tightBoundingRect ( const QString & text ) const

Returns a tight bounding rectangle around the characters in the string specified by text.

The bounding rectangle always covers at least the set of pixels the text would cover if drawn at (0, 0).

Note that the bounding rectangle may extend to the left of (0, 0), e.g. for italicized fonts, and that the width of the returned rectangle might be different than what the horizontalAdvance() method returns.

If you want to know the advance width of the string (to lay out a set of strings next to each other), use horizontalAdvance() instead.

Newline characters are processed as normal characters, not as linebreaks.

Since: 4.3

See also: horizontalAdvance(), height(), boundingRect()

Definition at line 821 of file qfontmetrics.cpp.

References QExplicitlySharedDataPointer< T >::data(), layout, qRound(), QString::size(), and text.

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◆ tightBoundingRect() [2/2]

QRect QFontMetrics::tightBoundingRect	(	const QString &	text,
		const QTextOption &	option ) const

Returns a tight bounding rectangle around the characters in the string specified by text laid out using option.

The bounding rectangle always covers at least the set of pixels the text would cover if drawn at (0, 0).

Note that the bounding rectangle may extend to the left of (0, 0), e.g. for italicized fonts, and that the width of the returned rectangle might be different than what the horizontalAdvance() method returns.

If you want to know the advance width of the string (to lay out a set of strings next to each other), use horizontalAdvance() instead.

Newline characters are processed as normal characters, not as linebreaks.

Since: 6.3

See also: horizontalAdvance(), height(), boundingRect()

Definition at line 853 of file qfontmetrics.cpp.

References QExplicitlySharedDataPointer< T >::data(), layout, qRound(), QString::size(), and text.

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◆ underlinePos()

int QFontMetrics::underlinePos ( ) const

Returns the distance from the base line to where an underscore should be drawn.

See also: overlinePos(), strikeOutPos(), lineWidth()

Definition at line 912 of file qfontmetrics.cpp.

References engine, QFontPrivate::engineForScript(), Q_ASSERT, and qRound().

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◆ xHeight()

int QFontMetrics::xHeight ( ) const

Returns the 'x' height of the font.

This is often but not always the same as the height of the character 'x'.

Definition at line 374 of file qfontmetrics.cpp.

References QFontEngine::ascent(), QFontPrivate::capital, engine, QFontPrivate::engineForScript(), Q_ASSERT, qRound(), QFont::SmallCaps, and QFontPrivate::smallCapsFontPrivate().

Referenced by lengthValueFromData().

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Friends And Related Symbol Documentation

◆ QFontMetricsF

friend class QFontMetricsF

friend

Definition at line 83 of file qfontmetrics.h.

◆ QStackTextEngine

friend class QStackTextEngine

friend

Definition at line 84 of file qfontmetrics.h.

The documentation for this class was generated from the following files:

qtbase/src/gui/text/qfontmetrics.h (314d86335ddd3ba8f67267c0e25b4df5fe0419c3)
qtbase/src/gui/text/qfontmetrics.cpp (132be307fff049e83ba8b93733fc571c0c45469b)

Public Member Functions

Friends

Detailed Description

Constructor & Destructor Documentation

◆ QFontMetrics() [1/3]

◆ QFontMetrics() [2/3]

◆ QFontMetrics() [3/3]

◆ ~QFontMetrics()

Member Function Documentation

◆ ascent()

◆ averageCharWidth()

◆ boundingRect() [1/5]

◆ boundingRect() [2/5]

◆ boundingRect() [3/5]

◆ boundingRect() [4/5]

◆ boundingRect() [5/5]

◆ capHeight()

◆ descent()

◆ elidedText()

◆ fontDpi()

◆ height()

◆ horizontalAdvance() [1/3]

◆ horizontalAdvance() [2/3]

◆ horizontalAdvance() [3/3]

◆ inFont()

◆ inFontUcs4()

◆ leading()

◆ leftBearing()

◆ lineSpacing()

◆ lineWidth()

◆ maxWidth()

◆ minLeftBearing()

◆ minRightBearing()

◆ operator!=()

◆ operator=()

◆ operator==()

◆ overlinePos()

◆ rightBearing()

◆ size()

◆ strikeOutPos()

◆ swap()

◆ tightBoundingRect() [1/2]

◆ tightBoundingRect() [2/2]

◆ underlinePos()

◆ xHeight()

Friends And Related Symbol Documentation

◆ QFontMetricsF

◆ QStackTextEngine