我有这个例子
\documentclass[12pt]{article}
\usepackage{xcolor}
\usepackage{fontspec}
\usepackage{bidi}
\setmainfont{Amiri}
\parindent=0pt
\begin{document}
{\color{red} text from left to right text from left to right \par
text from left to right text from left to right }
\hrulefill
\setRTL
\color{red} text from right to left text from right to left
\par text from right to left text from right to left \normalcolor
\hrulefill
{\color{red} text from right to left text from right to left \par
text from right to left text from right to left}
\hrulefill
{before \color{red} text from right to left text from right to left \par
text from right to left text from right to left}
\end{document}
有了这个结果
ltr（从左到右）的文本颜色很好，但 rtl 效果\color令人困惑，而且之前的文本也是\color彩色的！看起来命令是从段落的开头应用到结尾的，而不考虑命令的位置。
\documentclass[12pt]{article}
\usepackage{xcolor}
\usepackage{fontspec}
\usepackage{bidi}
\setmainfont{Amiri}
\parindent=0pt
\begin{document}
\setRTL
{\leavevmode\color{red} text from right to left text from right to left \par
text from right to left} text from right to left \par
text from right to left text from right to left
\end{document}
更新 2018/06/29
使用\addfontfeature{Color=red}（来自包的命令fontspec）可以这样解决问题
\documentclass[12pt]{article}
\usepackage{xcolor}
\usepackage{fontspec}
\usepackage{bidi}
\setmainfont{Amiri}
\parindent=0pt
\begin{document}
\setRTL
before {\addfontfeature{Color=red} text from right to left text from right to left \par
text from right to left} text from right to left \par
text from right to left text from right to left
\end{document}
我的目的是找到一种直接使用xcolor（或color）包而不依赖于包的方法fontspec。
答案1
有解决方案，但是除了您自己建议使用的一个解决方案之外，没有一个是好的fontspec：
% !TeX TS-program = xelatex
\documentclass[12pt]{article}
\usepackage{xcolor}
\usepackage{fontspec}
\usepackage{bidi}
\setmainfont{Amiri}
\parindent=0pt
\newcommand{\parnew}[1][red]{\par\color{#1}}
\begin{document}
{\color{red} text from left to right text from left to right \par
text from left to right text from left to right }
\hrulefill
\setRTL
{\color{red} text from right to left text from right to left
{\parnew text from right to left text from right to left} \normalcolor
}
\hrulefill
\newcommand{\mycolour}{blue}
{\color{\mycolour}{ text from right to left text from right to left \parnew[\mycolour]
text from right to left text from right to left}
}
\hrulefill
before {\color{red} text from right to left text from right to left} {\parnew
text from right to left text from right to left
}
\hrulefill
before \textcolor{red}{ text from right to left text from right to left }\par
\textcolor{red}{text from right to left text from right to left}
\hrulefill
\textcolor{black}{before} {\color{red}text from right to left text from right to left
text from right to left \textcolor{black}{text from right to left}
}
\hrulefill
before {\addfontfeature{Color=red} text from right to left text from right to left \par
text from right to left} text from right to left \par
text from right to left text from right to left
\hrulefill
\end{document}
