XeLaTeX 和 pdflatex 兼容代码（粗体问题）

Question

我正在尝试使用 pdflatex，并使用 XeLaTeX 和 pdflatex 将字体更改为希腊语。

XeLaTeX 运行完美，在章节标题中，它使用粗体选定的希腊语字体。但 pdflatex 无法使章节标题中的希腊语部分变为粗体。

我的代码（MWE 带有一些注释掉的替代测试）是这样的：

\def\UseXeLaTeX{1}

\documentclass[12pt]{article}

\ifnum\UseXeLaTeX=0
\usepackage[utf8]{inputenc} % utf8 is the preferred input encoding
\usepackage[greek.ancient,english]{babel} %koleygr:BF4 These coammnds are for LaTeX and pdflatex but we can't change font while changing language and thus we will use XeLaTeX
\usepackage[LGR,T1]{fontenc} %koleygr:BF4 Same as above
\else
\usepackage{polyglossia} %koleygr: Replacing commands to use XeLaTeX
\setmainlanguage{english}
\setotherlanguage{greek}
\fi

\ifnum\UseXeLaTeX=0
\usepackage{tgpagella} % Set the font TEX Gyre Pagella
\usepackage[scaled=0.875]{helvet} % Use helvetica for sans serif (phv)
\renewcommand{\sfdefault}{phv}
\usepackage{tgheros} %Use TeX Gyre Heros for greek (qhv)
\newcommand*{\mygreekfont}{\fontfamily{qhv}\selectfont}
\else
\setmainfont{TeX Gyre Pagella} 
\setsansfont[Ligatures=TeX]{TeX Gyre Heros}
\newfontfamily\helvet[Mapping=tex-text]{TeX Gyre Heros}
\newfontfamily\greekfont[Mapping=tex-text]{GFS Didot}
\fi

\newcommand{\fgreek}[1]{\ifnum\UseXeLaTeX=1 \textgreek{#1}\else\foreignlanguage{greek}{%\fontfamily{qhv}\selectfont
%\renewcommand{\familydefault}{qhv}
\mygreekfont #1}\fi}

\newenvironment{mygreek}{\ifnum\UseXeLaTeX=1 \begin{greek}\else\begin{otherlanguage}{greek}%\fontfamily{qhv}\selectfont
%\renewcommand{\familydefault}{qhv}
\mygreekfont
\fi}{\ifnum\UseXeLaTeX=1 \end{greek}\else\end{otherlanguage}\fi}

\begin{document}

\tableofcontents

\section{Test Section}
Test english text

\section{A phrase from \fgreek{Σωκράτης}}

\begin{mygreek}
 Ἓν οἶδα ὅτι οὐδὲν οἶδα
\end{mygreek}

\end{document}

XeLaTeX 输出是预期的：

但是 pdflatex 给出（经过所有测试）：

我做错了什么，还是字体问题？（字体应该是相同的，但 pdflatex 中的字体来自包）

Answer 1

使用\DeclareFontFamilySubstitution。

我把所有内容都改成\ifnum了\ifxetex构造。这样，只需要根据编译文档的引擎来选择适当的分支，而不需要修改文档本身。

\documentclass[12pt]{article}
\usepackage{ifxetex}

\ifxetex
  \usepackage{polyglossia} %koleygr: Replacing commands to use XeLaTeX
  \setmainlanguage{english}
  \setotherlanguage{greek}
\else
  \usepackage[LGR,T1]{fontenc}
  %\usepackage[utf8]{inputenc}
  \usepackage[greek.ancient,english]{babel}
\fi

\ifxetex
  \setmainfont{TeX Gyre Pagella} 
  \setsansfont[Ligatures=TeX]{TeX Gyre Heros}
  \newfontfamily\helvet[Mapping=tex-text]{TeX Gyre Heros}
  \newfontfamily\greekfont[Mapping=tex-text]{GFS Didot}
\else
  \usepackage{tgpagella} % Set the font TEX Gyre Pagella
  \usepackage[scaled=0.875]{helvet} % Use helvetica for sans serif (phv)
  \renewcommand{\sfdefault}{phv}
  \usepackage{tgheros} %Use TeX Gyre Heros for greek (qhv)
  \DeclareFontFamilySubstitution{LGR}{\rmdefault}{artemisia}
\fi

\ifxetex
  \newcommand{\fgreek}[1]{\textgreek{#1}}
  \newenvironment{mygreek}{\begin{greek}}{\end{greek}}
\else
  \newcommand{\fgreek}[1]{\foreignlanguage{greek}{#1}}
  \newenvironment{mygreek}
    {\begin{otherlanguage}{greek}}
    {\end{otherlanguage}}
\fi

\begin{document}

\tableofcontents

\section{Test Section}
Test english text

\section{A phrase from \fgreek{Σωκράτης}}

\begin{mygreek}
 Ἓν οἶδα ὅτι οὐδὲν οἶδα
\end{mygreek}

\end{document}

您可以artemisia使用任何支持希腊语的字体。

输出pdflatex

输出xelatex