QFontMetrics露

PyQt5.QtGui.QFontMetrics

Description露

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:

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.)
fontMetrics() returns the font metrics for a widget鈥檚 font. This is equivalent to QFontMetrics(widget->`font() <https://doc.qt.io/qt-5/stylesheet-reference.html#font>`_). If the widget鈥檚 font is changed later, the font metrics object is not updated.
fontMetrics() returns the font metrics for a painter鈥檚 current font. If the painter鈥檚 font is changed later, the font metrics object is not updated.

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 width(), 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 width(), to return the 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.

Example:

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

Methods露

__init__(QFont)

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鈥檚 attributes are changed later.

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

__init__(QFontMetrics): Constructs a copy of fm.

__init__(QFont, QPaintDevice)

Constructs a font metrics object for font and paintdevice.

The font metrics will be compatible with the paintdevice passed. If the paintdevice is 0, the metrics will be screen-compatible, ie. the metrics you get if you use the font for drawing text on a QWidget or QPixmap, 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鈥檚 attributes are changed later.

ascent() → int

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 an unusual character in an exotic language, so it is possible (though rare) that this value will be too small.

See also

descent().

averageCharWidth() → int: Returns the average width of glyphs in the font.

boundingRect(str) → QRect

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 width() 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().

boundingRect(QRect, int, str, tabStops: int = 0, tabArray: Optional[List[int]] = 0) → QRect: TODO

boundingRect(int, int, int, int, int, str, tabStops: int = 0, tabArray: Optional[List[int]] = 0) → QRect: TODO

boundingRectChar(str) → QRect

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 (const QString &) or horizontalAdvance() instead.

See also

width().

capHeight() → int: TODO

descent() → int

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 an unusual character in an exotic language, so it is possible (though rare) that this value will be too small.

See also

ascent().

elidedText(str, TextElideMode, int, flags: int = 0) → str

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

The mode parameter specifies whether the text is elided on the left (e.g., 鈥溾€ech鈥�), in the middle (e.g., 鈥淭r鈥h鈥�), or on the right (e.g., 鈥淭rol鈥︹€�).

The width is specified in pixels, not characters.

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

The elide mark follows the 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.

__eq__(QFontMetrics) → bool: TODO

fontDpi() → float: TODO

height() → int

Returns the height of the font.

This is always equal to descent.

See also

leading(), lineSpacing().

horizontalAdvance(str, length: int = -1) → int: TODO

inFont(str) → bool: Returns true if character ch is a valid character in the font; otherwise returns false.

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

leading() → int

Returns the leading of the font.

This is the natural inter-line spacing.

See also

height(), lineSpacing().

leftBearing(str) → int

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 width() for a graphical description of this metric.

lineSpacing() → int

Returns the distance from one base line to the next.

This value is always equal to height.

See also

height(), leading().

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

See also

underlinePos(), overlinePos(), strikeOutPos().

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

minLeftBearing() → int

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().

minRightBearing() → int

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().

__ne__(QFontMetrics) → bool: TODO

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

See also

underlinePos(), strikeOutPos(), lineWidth().

rightBearing(str) → int

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 width() of the character.

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

size(int, str, tabStops: int = 0, tabArray: Optional[List[int]] = 0) → QSize: TODO

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

See also

underlinePos(), overlinePos(), lineWidth().

swap(QFontMetrics): TODO

tightBoundingRect(str) → QRect

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 width() 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.

Warning: Calling this method is very slow on Windows.

See also

width(), height(), boundingRect().

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

See also

overlinePos(), strikeOutPos(), lineWidth().

width(str, length: int = -1) → int: TODO

widthChar(str) → int: TODO

xHeight() → int: Returns the 鈥榵鈥� height of the font. This is often but not always the same as the height of the character 鈥榵鈥�.