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 speci
fied, 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.
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 charac
ters 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 win
dow'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
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 substi
tuted 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 ``*'' char
acter 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 ele |
ment 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-fam |
ily-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 val |
ues. For compatibility, an XLFD always chooses a |
font of the specified pixel size (not point size); |
although this interpretation is not strictly cor |
rect, all existing applications using XLFDs assumed |
that one ``point'' was in fact one pixel and would |
display incorrectly (generally larger) if the cor |
rect 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
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 plat
forms 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 pat
terns, 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.
FONT OPTIONS
The following options are supported on all platforms, and
a font using style [5] as above:
-family name
The case-insensitive font family name. Tk guaran
tees 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 substi
tuted when one of the above font families is used.
The name may also be the name of a native, plat
form-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 abso |
lute 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, specify |
ing 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 com |
mand. |
-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 clos
est 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
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 mid
dle 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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