% Easy font substitution
% **********************
% 
% :Copyright: © 2010 Günter Milde
% 
% :Contributor: Special thanks to Ulrike Fischer who provided
%               the indirect definition with active ``\nfss@catcodes``.
% 
% :Licence:   This work may be distributed and/or modified under the
%             conditions of the `LaTeX Project Public License`_, either
%             version 1.3 of this license or any later version.
% 
% :Abstract: Provide the ``\substitutefont`` macro for defining
%            substitute fonts for specified font encodings.
% 
% :Identification:
%  ::

\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{substitutefont}
[2012/04/30 v0.1.1 combine font families]

% Changelog:
%   .. class:: borderless
% 
%   ============  ===== =================================================
%    2010-11-04   0.1   initial version
%    2012-04-30   0.1.1 documentation update, upload to CTAN
%   ============  ===== =================================================
% 
% 
% Usage
% =====
% 
% The macro ``\substitutefont{<encoding>}{<family>}{<new-family>}``
% selects the font <new-family> as replacement for <family> if the font
% encoding is <encoding> in the variants "normal", "italic", "slanted",
% and "small-caps" and the shapes "medium", "bold", and "bold-extended".
% 
% Example:
%   Use the `txtt` font family from txfonts_ instead of CM for
%   monospaced text (enables monospaced-bold as well as
%   monospaced-italic):
% 
%   ``\substitutefont{T1}{txtt}{cmtt}``
% 
% 
% Implementation
% ==============
% ::

\begingroup
\nfss@catcodes
\newcommand*{\substitutefont}[3]{%
 \DeclareFontFamily{#1}{#2}{}
 \DeclareFontShape{#1}{#2}{m}{n}{<->ssub * #3/m/n}{}
 \DeclareFontShape{#1}{#2}{m}{it}{<->ssub * #3/m/it}{}
 \DeclareFontShape{#1}{#2}{m}{sl}{<->ssub * #3/m/sl}{}
 \DeclareFontShape{#1}{#2}{m}{sc}{<->ssub * #3/m/sc}{}
 \DeclareFontShape{#1}{#2}{b}{n}{<->ssub * #3/b/n}{}
 \DeclareFontShape{#1}{#2}{b}{it}{<->ssub * #3/b/it}{}
 \DeclareFontShape{#1}{#2}{b}{sl}{<->ssub * #3/b/sl}{}
 \DeclareFontShape{#1}{#2}{b}{sc}{<->ssub * #3/b/sc}{}
 \DeclareFontShape{#1}{#2}{bx}{n}{<->ssub * #3/bx/n}{}
 \DeclareFontShape{#1}{#2}{bx}{it}{<->ssub * #3/bx/it}{}
 \DeclareFontShape{#1}{#2}{bx}{sl}{<->ssub * #3/bx/sl}{}
 \DeclareFontShape{#1}{#2}{bx}{sc}{<->ssub * #3/bx/sc}{}
}
\global\let\substitutefont\substitutefont
\endgroup

% .. _LaTeX Project Public License: http://www.latex-project.org/lppl.txt
% .. _txfonts: http://mirror.ctan.org/help/Catalogue/entries/txfonts.html