font(n) Tk (8.0) font(n)
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NAME
font - Create and inspect fonts.
SYNOPSIS
font option ?arg arg ...?
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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 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-dependant
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.
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font(n) Tk (8.0) font(n)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
exagerrated 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
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font(n) Tk (8.0) font(n)
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
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font(n) Tk (8.0) font(n)
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-dependant 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
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.
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font(n) Tk (8.0) font(n)
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
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font(n) Tk (8.0) font(n)
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.
PLATFORM-SPECIFIC ISSUES
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
Macintosh:
system application
SEE ALSO
options
KEYWORDS
font
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