Note that these commands can also be used outside a font definition file: they can be put in package or class files, or even in the preamble of a document.
\ProvidesFile{<file-name>}[<release-info>]
The file should announce itself with a \ProvidesFile command,
as described in LaTeX2e for Class and Package Writers. For example:
\ProvidesFile{t1ptm.fd}[1994/06/01 Adobe Times font definitions]
\DeclareFontFamily {<encoding>} {<family>} {<loading-settings>}
Declares a font family <family> to be available in encoding scheme <encoding>. The <loading-settings> are executed immediately after loading any font with this encoding and family. Checks that <encoding> was previously declared. This example refers to the Computer Modern Typewriter font family in the Cork encoding:
\DeclareFontFamily{T1}{cmtt}{\hyphenchar\font=-1}
Each .fd file should contain exactly one \DeclareFontFamily
command, and it should be for the appropriate encoding/family
combination.
\DeclareFontShape {<encoding>} {<family>} {<series>}
{<shape>}
{<loading-info>} {<loading-settings>}
Declares a font shape combination; here <loading-info> contains the
information that combines sizes with external fonts. The syntax is
complex and is described in Section 4.3 below.
The <loading-settings> are executed after loading any font with this
font shape. They are executed immediately after the
`loading-settings' which were declared by \DeclareFontFamily and so
they can be used to overwrite the settings made at the family level.
Checks that the combination <encoding><family> was previously
declared via \DeclareFontFamily.
Example:
\DeclareFontShape{OT1}{cmr}{m}{sl}{%
<<5-8>> sub * cmr/m/n
<<8>> cmsl8
<<9>> cmsl9
<<10>> <<10.95>> cmsl10
<<12>> <<14.4>> <<17.28>> <<20.74>> <<24.88>> cmsl12
}{}
The file can contain any number of \DeclareFontShape commands,
which should be for the appropriate <encoding> and <family>.
The font family declarations for the OT1-encoded fonts now all
contain:
\hyphenchar\font=`\-This enables the use of an alternative
\hyphenchar in other encodings
whilst maintaining the correct value for all fonts.