Provided by: tk8.5-doc_8.5.19-3_all 
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? ?--? ?char?
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. If the char argument is supplied, it must be a
single character. The font attributes returned will be those of the specific font
used to render that character, which will be different from the base font if the
base font does not contain the given character. If char may be a hyphen, it should
be preceded by -- to distinguish it from a misspelled option.
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 will not 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.
STANDARD FONTS
The following named fonts are supported on all systems, and default to values that match
appropriate system defaults.
TkDefaultFont
This font is the default for all GUI items not otherwise specified.
TkTextFont
This font should be used for user text in entry widgets, listboxes etc.
TkFixedFont
This font is the standard fixed-width font.
TkMenuFont
This font is used for menu items.
TkHeadingFont
This font should be used for column headings in lists and tables.
TkCaptionFont
This font should be used for window and dialog caption bars.
TkSmallCaptionFont
This font should be used for captions on contained windows or tool dialogs.
TkIconFont
This font should be used for icon captions.
TkTooltipFont
This font should be used for tooltip windows (transient information windows).
It is not advised to change these fonts, as they may be modified by Tk itself in response
to system changes. Instead, make a copy of the font and modify that.
PLATFORM-SPECIFIC FONTS
The following system fonts are supported:
X Windows
All valid X font names, including those listed by xlsfonts(1), are available.
MS Windows
The following fonts are supported, and are mapped to the user's style defaults.
system ansi device
systemfixed ansifixed oemfixed
Mac OS X
The following fonts are supported, and are mapped to the user's style defaults.
system application menu
Additionally, the following named fonts provide access to the Aqua theme fonts:
systemSystemFont systemEmphasizedSystemFont
systemSmallSystemFontsystemSmallEmphasizedSystemFont
systemApplicationFontsystemLabelFont
systemViewsFont systemMenuTitleFont
systemMenuItemFont systemMenuItemMarkFont
systemMenuItemCmdKeyFontsystemWindowTitleFont
systemPushButtonFontsystemUtilityWindowTitleFont
systemAlertHeaderFontsystemToolbarFont
systemMiniSystemFontsystemDetailSystemFont
systemDetailEmphasizedSystemFont
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