Starting with Emacs 23, fonts are specified by their name, size and optional properties. The format for specifying fonts comes from the fontconfig library used in modern Free desktops:
The old XLFD based format is also supported for backwards compatibility.
Emacs 23 and later supports a number of font backends. Currently,
uniscribe backends are supported on Windows.
gdi font backend is available on all versions of Windows,
and supports all fonts that are natively supported by Windows. The
uniscribe font backend is available on Windows 2000 and later,
and supports TrueType and OpenType fonts. Some languages requiring
complex layout can only be properly supported by the Uniscribe
backend. By default, both backends are enabled if supported, with
uniscribe taking priority over
gdi. To override that
and use the GDI backend even if Uniscribe is available, invoke Emacs
with the -xrm Emacs.fontBackend:gdi command-line argument, or
Emacs.fontBackend resource with the value
the Registry under either the
‘HKEY_CURRENT_USER\SOFTWARE\GNU\Emacs’ or the
‘HKEY_LOCAL_MACHINE\SOFTWARE\GNU\Emacs’ key (see Resources).
Optional properties common to all font backends on MS-Windows are:
Specifies the weight of the font. Special values
black can be specified
weight= (e.g., Courier New-12:bold). Otherwise,
the weight should be a numeric value between 100 and 900, or one of the
named weights in
font-weight-table. If unspecified, a regular font
Specifies whether the font is italic. Special values
oblique can be specified
slant= (e.g., Courier New-12:italic).
Otherwise, the slant should be a numeric value, or one of the named
font-slant-table. On Windows, any slant above 150 is
treated as italics, and anything below as roman.
Specifies the font family, but normally this will be specified at the start of the font name.
Specifies the font size in pixels. This can be used instead of the point size specified after the family name.
Specifies additional style information for the font.
On MS-Windows, the values
decorative are recognized. These are most useful
as a fallback with the font family left unspecified.
Specifies the character set registry that the font is
expected to cover. Most TrueType and OpenType fonts will be Unicode fonts
that cover several national character sets, but you can narrow down the
selection of fonts to those that support a particular character set by
using a specific registry from
Specifies how the font is spaced. The
p spacing specifies
a proportional font, and
c specify a monospaced font.
Not used on Windows, but for informational purposes and to
prevent problems with code that expects it to be set, is set internally to
raster for bitmapped fonts,
outline for scalable fonts,
unknown if the type cannot be determined as one of those.
Options specific to
Specifies a Unicode subrange the font should support.
The following scripts are recognized on Windows:
Specifies the antialiasing method. The value
none means no
standard means use standard antialiasing,
subpixel means use subpixel antialiasing (known as Cleartype on
natural means use subpixel antialiasing with
adjusted spacing between letters. If unspecified, the font will use
the system default antialiasing.