NAME¶
font - Create and inspect fonts.
SYNOPSIS¶
font option ?
arg arg ...?
DESCRIPTION¶
The
font command provides several facilities for dealing with fonts, such
as defining named fonts and inspecting the actual attributes of a font. The
command has several different forms, determined by the first argument. The
following forms are currently supported:
- font actual font ?-displayof
window? ? option?
- Returns information about the actual attributes that are
obtained when font is used on window's display; the actual
attributes obtained may differ from the attributes requested due to
platform-dependent limitations, such as the availability of font families
and pointsizes. font is a font description; see FONT DESCRIPTIONS
below. If the window argument is omitted, it defaults to the main
window. If option is specified, returns the value of that
attribute; if it is omitted, the return value is a list of all the
attributes and their values. See FONT OPTIONS below for a list of the
possible attributes.
- font configure fontname ?option?
?value option value ...?
- Query or modify the desired attributes for the named font
called fontname. If no option is specified, returns a list
describing all the options and their values for fontname. If a
single option is specified with no value, then returns the
current value of that attribute. If one or more option-value
pairs are specified, then the command modifies the given named font to
have the given values; in this case, all widgets using that font will
redisplay themselves using the new attributes for the font. See FONT
OPTIONS below for a list of the possible attributes.
- font create ?fontname? ?option value
...?
- Creates a new named font and returns its name.
fontname specifies the name for the font; if it is omitted, then Tk
generates a new name of the form fontx, where x is an
integer. There may be any number of option-value pairs,
which provide the desired attributes for the new named font. See FONT
OPTIONS below for a list of the possible attributes.
- font delete fontname ?fontname
...?
- Delete the specified named fonts. If there are widgets
using the named font, the named font won't actually be deleted until all
the instances are released. Those widgets will continue to display using
the last known values for the named font. If a deleted named font is
subsequently recreated with another call to font create, the
widgets will use the new named font and redisplay themselves using the new
attributes of that font.
- font families ?-displayof window?
- The return value is a list of the case-insensitive names of
all font families that exist on window's display. If the
window argument is omitted, it defaults to the main window.
- font measure font ?-displayof
window? text
- Measures the amount of space the string text would
use in the given font when displayed in window. font
is a font description; see FONT DESCRIPTIONS below. If the window
argument is omitted, it defaults to the main window. The return value is
the total width in pixels of text, not including the extra pixels
used by highly exaggerated characters such as cursive ``f''. If the string
contains newlines or tabs, those characters are not expanded or treated
specially when measuring the string.
- font metrics font ?-displayof
window? ? option?
- Returns information about the metrics (the font-specific
data), for font when it is used on window's display.
font is a font description; see FONT DESCRIPTIONS below. If the
window argument is omitted, it defaults to the main window. If
option is specified, returns the value of that metric; if it is
omitted, the return value is a list of all the metrics and their values.
See FONT METRICS below for a list of the possible metrics.
- font names
- The return value is a list of all the named fonts that are
currently defined.
FONT DESCRIPTION¶
The following formats are accepted as a font description anywhere
font is
specified as an argument above; these same forms are also permitted when
specifying the
-font option for widgets.
- [1] fontname
- The name of a named font, created using the font
create command. When a widget uses a named font, it is guaranteed that
this will never cause an error, as long as the named font exists, no
matter what potentially invalid or meaningless set of attributes the named
font has. If the named font cannot be displayed with exactly the specified
attributes, some other close font will be substituted automatically.
- [2] systemfont
- The platform-specific name of a font, interpreted by the
graphics server. This also includes, under X, an XLFD (see [4]) for which
a single `` *'' character was used to elide more than one field in
the middle of the name. See PLATFORM-SPECIFIC issues for a list of the
system fonts.
- [3] family ?size? ?style? ?style
...?
- A properly formed list whose first element is the desired
font family and whose optional second element is the desired
size. The interpretation of the size attribute follows the
same rules described for -size in FONT OPTIONS below. Any
additional optional arguments following the size are font
styles. Possible values for the style arguments are as
follows:
normal bold roman italic
underline overstrike
- [4] X-font names (XLFD)
- A Unix-centric font name of the form
-foundry-family-weight-slant-setwidth-addstyle-pixel-point-resx-resy-spacing-width-charset-encoding.
The `` *'' character may be used to skip individual fields that the
user does not care about. There must be exactly one `` *'' for each
field skipped, except that a `` *'' at the end of the XLFD skips
any remaining fields; the shortest valid XLFD is simply `` *'',
signifying all fields as defaults. Any fields that were skipped are given
default values. For compatibility, an XLFD always chooses a font of the
specified pixel size (not point size); although this interpretation is not
strictly correct, all existing applications using XLFDs assumed that one
``point'' was in fact one pixel and would display incorrectly (generally
larger) if the correct size font were actually used.
- [5] option value ?option value ...?
- A properly formed list of option-value pairs
that specify the desired attributes of the font, in the same format used
when defining a named font; see FONT OPTIONS below.
When font description
font is used, the system attempts to parse the
description according to each of the above five rules, in the order specified.
Cases [1] and [2] must match the name of an existing named font or of a system
font. Cases [3], [4], and [5] are accepted on all platforms and the closest
available font will be used. In some situations it may not be possible to find
any close font (e.g., the font family was a garbage value); in that case, some
system-dependent default font is chosen. If the font description does not
match any of the above patterns, an error is generated.
FONT METRICS¶
The following options are used by the
font metrics command to query
font-specific data determined when the font was created. These properties are
for the whole font itself and not for individual characters drawn in that
font. In the following definitions, the ``baseline'' of a font is the
horizontal line where the bottom of most letters line up; certain letters,
such as lower-case ``g'' stick below the baseline.
- -ascent
- The amount in pixels that the tallest letter sticks up
above the baseline of the font, plus any extra blank space added by the
designer of the font.
- -descent
- The largest amount in pixels that any letter sticks down
below the baseline of the font, plus any extra blank space added by the
designer of the font.
- -linespace
- Returns how far apart vertically in pixels two lines of
text using the same font should be placed so that none of the characters
in one line overlap any of the characters in the other line. This is
generally the sum of the ascent above the baseline line plus the descent
below the baseline.
- -fixed
- Returns a boolean flag that is ``1'' if this is a
fixed-width font, where each normal character is the same width as all the
other characters, or is `` 0'' if this is a proportionally-spaced
font, where individual characters have different widths. The widths of
control characters, tab characters, and other non-printing characters are
not included when calculating this value.
FONT OPTIONS¶
The following options are supported on all platforms, and are used when
constructing a named font or when specifying a font using style [5] as above:
- -family name
- The case-insensitive font family name. Tk guarantees to
support the font families named Courier (a monospaced
``typewriter'' font), Times (a serifed ``newspaper'' font), and
Helvetica (a sans-serif ``European'' font). The most closely
matching native font family will automatically be substituted when one of
the above font families is used. The name may also be the name of a
native, platform-specific font family; in that case it will work as
desired on one platform but may not display correctly on other platforms.
If the family is unspecified or unrecognized, a platform-specific default
font will be chosen.
- -size size
- The desired size of the font. If the size argument
is a positive number, it is interpreted as a size in points. If
size is a negative number, its absolute value is interpreted as a
size in pixels. If a font cannot be displayed at the specified size, a
nearby size will be chosen. If size is unspecified or zero, a
platform-dependent default size will be chosen.
Sizes should normally be specified in points so the application will remain the
same ruler size on the screen, even when changing screen resolutions or moving
scripts across platforms. However, specifying pixels is useful in certain
circumstances such as when a piece of text must line up with respect to a
fixed-size bitmap. The mapping between points and pixels is set when the
application starts, based on properties of the installed monitor, but it can
be overridden by calling the
tk scaling command.
- -weight weight
- The nominal thickness of the characters in the font. The
value normal specifies a normal weight font, while bold
specifies a bold font. The closest available weight to the one specified
will be chosen. The default weight is normal.
- -slant slant
- The amount the characters in the font are slanted away from
the vertical. Valid values for slant are roman and italic. A
roman font is the normal, upright appearance of a font, while an italic
font is one that is tilted some number of degrees from upright. The
closest available slant to the one specified will be chosen. The default
slant is roman.
- -underline boolean
- The value is a boolean flag that specifies whether
characters in this font should be underlined. The default value for
underline is false.
- -overstrike boolean
- The value is a boolean flag that specifies whether a
horizontal line should be drawn through the middle of characters in this
font. The default value for overstrike is false.
The following named system fonts are supported:
- X Windows:
- All valid X font names, including those listed by
xlsfonts(1), are available.
- MS Windows:
system ansi device
systemfixed ansifixed oemfixed
- Mac OS X:
EXAMPLE¶
Fill a text widget with lots of font demonstrators, one for every font family
installed on your system:
pack [text .t -wrap none] -fill both -expand 1
set count 0
set tabwidth 0
foreach family [lsort -dictionary [ font families]] {
.t tag configure f[incr count] -font [list $family 10]
.t insert end ${family}:\t {} \
"This is a simple sampler\n" f$count
set w [ font measure [.t cget -font] ${family}:]
if {$w+5 > $tabwidth} {
set tabwidth [expr {$w+5}]
.t configure -tabs $tabwidth
}
}
SEE ALSO¶
options(3tk)
KEYWORDS¶
font