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.so man.macros

.TH font n 8.0 Tk "Tk Built-In Commands"

.BS

'\" Note:  do not modify the .SH NAME line immediately below!

.SH NAME

font \- Create and inspect fonts.

.SH SYNOPSIS

\fBfont\fI option \fR?\fIarg arg ...\fR?

.BE

.SH DESCRIPTION

.PP

The \fBfont\fR 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:

.TP

\fBfont actual \fIfont\fR ?\fB\-displayof \fIwindow\fR? ?\fIoption\fR?

.

Returns information about the the actual attributes that are obtained when

\fIfont\fR is used on \fIwindow\fR'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.

\fIfont\fR is a font description; see FONT DESCRIPTIONS below.  If the

\fIwindow\fR argument is omitted, it defaults to the main window.  If

\fIoption\fR 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.

.TP

\fBfont configure \fIfontname\fR ?\fIoption\fR? ?\fIvalue option value ...\fR?

.

Query or modify the desired attributes for the named font called

\fIfontname\fR.  If no \fIoption\fR is specified, returns a list describing

all the options and their values for \fIfontname\fR.  If a single \fIoption\fR

is specified with no \fIvalue\fR, then returns the current value of that

attribute.  If one or more \fIoption\fR\-\fIvalue\fR 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.

.TP

\fBfont create\fR ?\fIfontname\fR? ?\fIoption value ...\fR?

.

Creates a new named font and returns its name.  \fIfontname\fR specifies the

name for the font; if it is omitted, then Tk generates a new name of the

form \fBfont\fIx\fR, where \fIx\fR is an integer.  There may be any number

of \fIoption\fR\-\fIvalue\fR pairs, which provide the desired attributes for

the new named font.  See FONT OPTIONS below for a list of the possible

attributes.

.TP

\fBfont delete\fR \fIfontname\fR ?\fIfontname ...\fR?

.

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 \fBfont create\fR, the widgets will use the new named font

and redisplay themselves using the new attributes of that font.

.TP

\fBfont families\fR ?\fB\-displayof \fIwindow\fR?

.

The return value is a list of the case-insensitive names of all font families

that exist on \fIwindow\fR's display.  If the \fIwindow\fR argument is

omitted, it defaults to the main window.

.TP

\fBfont measure \fIfont\fR ?\fB\-displayof \fIwindow\fR? \fItext\fR

.

Measures the amount of space the string \fItext\fR would use in the given

\fIfont\fR when displayed in \fIwindow\fR.  \fIfont\fR is a font description;

see FONT DESCRIPTIONS below.  If the \fIwindow\fR argument is omitted, it

defaults to the main window.  The return value is the total width in pixels

of \fItext\fR, 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.

.TP

\fBfont metrics \fIfont\fR ?\fB\-displayof \fIwindow\fR? ?\fIoption\fR?

.

Returns information about the metrics (the font-specific data), for

\fIfont\fR when it is used on \fIwindow\fR's display.  \fIfont\fR is a font

description; see FONT DESCRIPTIONS below.  If the \fIwindow\fR argument is

omitted, it defaults to the main window.  If \fIoption\fR 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.

.TP

\fBfont names\fR

The return value is a list of all the named fonts that are currently defined.

.SH "FONT DESCRIPTION"

.PP

The following formats are accepted as a font description anywhere

\fIfont\fR is specified as an argument above; these same forms are also

permitted when specifying the \fB\-font\fR option for widgets.

.TP

[1] \fIfontname\fR

.

The name of a named font, created using the \fBfont create\fR 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.

.TP

[2] \fIsystemfont\fR

.

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 ``\fB*\fR''

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.

.VS 8.0 br

.TP

[3] \fIfamily \fR?\fIsize\fR? ?\fIstyle\fR? ?\fIstyle ...\fR?

.

A properly formed list whose first element is the desired font

\fIfamily\fR and whose optional second element is the desired \fIsize\fR.

The interpretation of the \fIsize\fR attribute follows the same rules

described for \fB\-size\fR in FONT OPTIONS below.  Any additional optional

arguments following the \fIsize\fR are font \fIstyle\fRs.  Possible values

for the \fIstyle\fR arguments are as follows:

.RS

.DS

.ta 3c 6c 9c

\fBnormal       bold    roman   italic

underline       overstrike\fR

.DE

.RE

.TP

[4] X-font names (XLFD)

.

A Unix-centric font name of the form

\fI-foundry-family-weight-slant-setwidth-addstyle-pixel-point-resx-resy-spacing-width-charset-encoding\fR.

The ``\fB*\fR'' character may be used to skip individual fields that the

user does not care about.  There must be exactly one ``\fB*\fR'' for each

field skipped, except that a ``\fB*\fR'' at the end of the XLFD skips any

remaining fields; the shortest valid XLFD is simply ``\fB*\fR'', 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.

.VE

.TP

[5] \fIoption value \fR?\fIoption value ...\fR?

.

A properly formed list of \fIoption\fR\-\fIvalue\fR pairs that specify

the desired attributes of the font, in the same format used when defining

a named font; see FONT OPTIONS below.

.LP

When font description \fIfont\fR 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.

.SH "FONT METRICS"

.

The following options are used by the \fBfont metrics\fR 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.

.TP

\fB\-ascent        \0\fR

.

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.

.TP

\fB\-descent       \0\fR

.

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.

.TP

\fB\-linespace\fR

.

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.

.TP

\fB\-fixed          \0\fR

.

Returns a boolean flag that is ``\fB1\fR'' if this is a fixed-width font,

where each normal character is the the same width as all the other

characters, or is ``\fB0\fR'' 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.

.SH "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:

.TP

\fB\-family \fIname\fR

.

The case-insensitive font family name.  Tk guarantees to support the font

families named \fBCourier\fR (a monospaced ``typewriter'' font), \fBTimes\fR

(a serifed ``newspaper'' font), and \fBHelvetica\fR (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 \fIname\fR 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.

.VS

.TP

\fB\-size \fIsize\fR

.

The desired size of the font.  If the \fIsize\fR argument is a positive

number, it is interpreted as a size in points.  If \fIsize\fR 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 \fIsize\fR is unspecified or zero, a platform-dependent default

size will be chosen.

.RS

.PP

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 \fBtk scaling\fR command.

.RE

.VE

.TP

\fB\-weight \fIweight\fR

.

The nominal thickness of the characters in the font.  The value

\fBnormal\fR specifies a normal weight font, while \fBbold\fR specifies a

bold font.  The closest available weight to the one specified will

be chosen.  The default weight is \fBnormal\fR.

.TP

\fB\-slant \fIslant\fR

The amount the characters in the font are slanted away from the

vertical.  Valid values for slant are \fBroman\fR and \fBitalic\fR.

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 \fBroman\fR.

.TP

\fB\-underline \fIboolean\fR

The value is a boolean flag that specifies whether characters in this

font should be underlined.  The default value for underline is \fBfalse\fR.

.TP

\fB\-overstrike \fIboolean\fR

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 \fBfalse\fR.

.SH "PLATFORM-SPECIFIC ISSUES"

.LP

The following named system fonts are supported:

.RS

.TP

X Windows:

All valid X font names, including those listed by xlsfonts(1), are available.

.TP

MS Windows:

.DS

\fBsystem       ansi    device

systemfixed     ansifixed       oemfixed\fR

.DE

.TP

Macintosh:

.DS

\fBsystem       application\fR

.DE

.RE

.SH "SEE ALSO"

options

.SH KEYWORDS

font