addfont4ht.sty

% This package declares new font family in the CSS file
% Usage:
%
% \NormalFont{FontFamilyName}{normal-font-file.otf}
% \BoldFont{FontFamilyName}{bold-font-file.otf}
% \BoldItalicFont{FontFamilyName}{bold-italic-font-file.otf}
% \ItalicFont{FontFamilyName}{italic-font-file.otf}
% \Css{body{font-family: rmfamily, "FontFamilyName", serif;}}
% 
% The default font family name for a declared font is rmfamily
% It can be changed using \SetFontFamily command.

% It is necessary to provide three names
% #1 font family name that will be used later in the user CSS
% #2 font family from the user file system, which will be used if available (so downloading of the fonts is not necessary)
% #3 filename of the font which should be used if the local version is not available
\RequirePackage{include4ht}
\newcommand\AddFontFace[4]{%
\Css{@font-face {
    font-family: #1;
    src: local("#2"),
        url('#3');
    #4
 }}
\AddFile{#3}
}

% The default font family declared by font definition commands
\edef\CurrentFontFamily{rmfamily}

% If more font families are used, they need to have different names
\newcommand\SetFontFamily[1]{
\edef\CurrentFontFamily{#1}
}


% Declarations for common font styles, just local family name and font file name are needed to be provided
\newcommand\NormalFont[2]{\AddFontFace{\CurrentFontFamily}{#1}{#2}{font-weight: normal;font-style: normal;}}
\newcommand\BoldFont[2]{\AddFontFace{\CurrentFontFamily}{#1}{#2}{font-weight: bold;font-style: normal;}}
\newcommand\ItalicFont[2]{\AddFontFace{\CurrentFontFamily}{#1}{#2}{font-weight: normal;font-style: italic;}}
\newcommand\BoldItalicFont[2]{\AddFontFace{\CurrentFontFamily}{#1}{#2}{font-weight: bold;font-style: italic;}}