在下面的 MWE 中，我希望红色褪色 - tikz - 矩形线强调这三个“subtiles”。在我开始修修补补和猜测之前：如何巧妙地实现这一点？
\PassOptionsToPackage{svgnames}{xcolor}
\documentclass[a4paper]{article}
\usepackage[framemethod=TikZ]{mdframed}
\usepackage{colortbl}
\newlength{\mycustomlength}
\settowidth\mycustomlength{abcdefghiblablab}
\usepackage{tabularx}
\usepackage{multirow}
\begin{document}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{tabularx}{\textwidth}{@{}*{1}{p{\mycustomlength}}*{1}{X}@{}} % sub-headings modification
\multicolumn{2}{@{}l}{\sbox0{\textsc{\color{black}Some Subtitle}\phantom{M}}\usebox0 \tikz[baseline=-0.5ex] \shade[left color=red, right color=white] (0,0) rectangle ({\linewidth-\wd0},-0.02);}
\\
bla bla bla bla! & blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla. blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla.blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla.blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla.
\\
\multicolumn{2}{@{}l}{\sbox0{\textsc{\color{black}Another Subtitle}\phantom{M}}\usebox0 \tikz[baseline=-0.5ex] \shade[left color=red, right color=white] (0,0) rectangle ({\linewidth-\wd0},-0.02);}
\\
bla bla bla bla! & blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla. blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla.blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla.blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla.
\\
\multicolumn{2}{@{}l}{\sbox0{\underline{\textsc{\color{black}And A Third Subtitle}}\phantom{M}}\usebox0 \tikz[baseline=-0.5ex] \shade[left color=red, right color=white] (0,0) rectangle ({\linewidth-\wd0},-0.02);}
\\
bla bla bla bla! & blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla. blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla.blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla.blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla.
\\
\end{tabularx}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\end{document}
期望的结果：
编辑
到目前为止的答案已经提供了用 tikz 取代标准下划线的良好尝试/解决方案。
此外，我很高兴看到 MWE，其中 tikz 下划线的长度与文本长度分离，也就是说，行的长度是独立于文本长度确定和固定的。
答案1
另一种解决方案。
我的命令和 Ignasi 的很像。我发誓我没有作弊！
输出
代码
\documentclass[12pt]{article}
\usepackage{tikz}
\usetikzlibrary{backgrounds}
\usepackage{tabularx}
\usepackage{multirow}
\begin{document}
\newcommand\miniTikzUl[2][]
{%
\begin{tikzpicture}[baseline=(a.base)]
\node[inner sep=0pt] (a) {#2\strut};
\begin{scope}[on background layer]
\shade[left color=red!80, right color=white,#1]
([yshift=-.3mm]a.base east) rectangle ([yshift=-.7mm]a.base west);
\end{scope}
\end{tikzpicture}%
}
\paragraph{Test Underlining}~
\noindent\hrulefill
\underline{underlined} \underline{underlinedWithStrut\strut}
\miniTikzUl[opacity=.5]{\underline{underlined} \underline{underlinedWithStrut\strut} duTexte}
blabla blabla blabla blabla blabla blabla blabla blabla
\miniTikzUl[left color=blue,]{duTexte blabla blabla}
blabla blabla blabla blabla blabla blabla blabla
\noindent\hrulefill
\paragraph{Test Tabularx}~\\
\newcommand\mySubtitle[2][]
{%
%\multicolumn{2}{@{}l}{\miniTikzUl[#1]{#2}}%
\strut\rlap{\miniTikzUl[#1]{#2}} &
}
\newcommand\myRow%
{%
bla bla bla bla! & blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla. blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. %
bla.blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla.blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla. %
}
%\noindent
%\begin{tabular}{ll}
% \mySubtitle{Some Subtitle} \\
% \myRow \\
% \mySubtitle{Another Subtitle} \\
% \myRow \\
% \mySubtitle{And a Third Subtitle} \\
% \myRow \\
%\end{tabular}
\noindent
\begin{tabularx}{\textwidth}{@{}*{1}{p{3cm}}*{1}{X}@{}} % sub-headings modification
\mySubtitle{Some Subtitle} \\
\myRow \\
\mySubtitle{Another Subtitle gjpq} \\
\myRow \\
\mySubtitle[opacity=.6, left color=black]{And a Third Subtitle} \\
\myRow \\
\end{tabularx}
\end{document}
更多变体
输出
代码
\documentclass[12pt]{article}
\usepackage{calc}
\usepackage{tikz}
\usetikzlibrary{backgrounds}
\usepackage{tabularx}
\usepackage{multirow}
\newlength\ambientLinewidth
\AtBeginDocument{\setlength\ambientLinewidth{\linewidth}}
\begin{document}
\thispagestyle{empty}
\newcommand\miniTikzUl[2][]
{%
\begin{tikzpicture}[baseline=(a.base)]
\node[inner sep=0pt] (a) {#2\strut};
\begin{scope}[on background layer]
\shade[left color=red!80, right color=white,#1]
([yshift=-.3mm]a.base east) rectangle ([yshift=-.7mm]a.base west);
\end{scope}
\end{tikzpicture}%
}
\newcommand\mySubtitle[2][]
{%
\strut\rlap{\miniTikzUl[#1]{\textsc{#2}}} &
}
\newcommand\shortenedSubtitle[3][]
{
\mySubtitle[#1]{#3\hspace{-#2}}
}
\newcommand\exactLength[3][]
{
\mySubtitle[#1]{\hbox{}\rlap{#3}\hphantom{\rule{#2}{0pt}}}
}
\newcommand\myRow%
{%
texte à gauche & texte à droite
}
\noindent
\begin{tabularx}{\textwidth}{@{}*{1}{p{3cm}}*{1}{X}@{}} % sub-headings modification
\exactLength{2mm}{Exactly 2mm} \\
\myRow \\
\shortenedSubtitle[right color=blue]{2cm}{Subtitle with 2cm less} \\
\myRow \\
\mySubtitle[right color=blue]{These commands seem a bit redundant, though\hspace{-5cm}\rlap{\raisebox{-.5mm}{\color{green}\rule{5cm}{.5pt}}}} \\
I recommend \rlap{instead you read about : } &
\begin{itemize}
\item \verb|\rlap| \item \verb|\hspace| \item \verb|\rule| \item \verb|\phantom|
\end{itemize}
It will change your life (\emph{or maybe not !}) \\
\\
\strut\rlap{\textsc{The full line, \emph{no complicated command needed...}}}%
\raisebox{-.7mm}
{%
\noindent\tikz\shade[left color=orange!50!yellow, right color=purple!50!blue]
(0,0) rectangle (\ambientLinewidth,-.4mm);
}
\\
\myRow \\
\end{tabularx}
\noindent\hrulefill
\paragraph{debugging}~
\verb|\the\linewidth| \the\linewidth
\verb|\the\ambientLinewidth| \the\ambientLinewidth
\begin{description}
\item [baseline for tikzpics] a\tikz[baseline=(a.base)]\node[inner sep=0pt](a){a};
\end{description}
\end{document}
答案2
这个答案很大程度上受到了讨论的启发 这里
我首先从以下网址下载了 Martin Scharrer 的代码：https://bitbucket.org/martin_scharrer/tikzpagelayers。
并定义以下命令，tikzshll类似于现有的tikzshl，只是具有您可能喜欢的阴影和厚度。
\newcommand\tikzshll[2][]{%
\begingroup
\tikzpagelayer[background]{\shade [line width=.5cm,left color=#1, right
color=white] (tplbegin) ++(0,-.1\dp\strutbox)
rectangle (tplend);}%
#2%
\endtikzpagelayer
\endgroup
}
如果需要肯定下划线和文本之间的距离（注意；这需要\usetikzlibrary{calc}，已在原始样式文件中使用。）
\newcommand\tikzshll[2][]{%
\begingroup
\tikzpagelayer[background]{\shade [line width=.5cm,left color=#1, right
color=white] ($(tplbegin) + (0, -0.1em)$) ++(0,-.1\dp\strutbox)
rectangle ($(tplend) + (0, -0.1em)$);}%
#2%
\endtikzpagelayer
\endgroup
}
并像这样使用它；
\PassOptionsToPackage{svgnames}{xcolor}
\documentclass[a4paper]{article}
\usepackage[framemethod=TikZ]{mdframed}
\usepackage{colortbl}
\newlength{\mycustomlength}
\settowidth\mycustomlength{abcdefghiblablab}
\usepackage{tabularx}
\usepackage{multirow}
% Added this
\usepackage{tikzpagelayers}
\begin{document}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{tabularx}{\textwidth}{@{}*{1}{p{\mycustomlength}}*{1}{X}@{}} %
%sub-headings modification
\multicolumn{2}{@{}l}{\tikzshll[red]{Some Subtitle}}
\\
bla bla bla bla! & blaaaaaaaaaaaaa \tikzshll[purple]{blaaaaaaaaaaaaaaa.} bla.
blaaaaaaaaaaaaa
blaaaaaaaaaaaaaaa. bla.blaaaaaaaaaaaaa \tikzshll[black]{blaaaaaaaaaaaaaaa.}
bla.blaaaaaaaaaaaaa
blaaaaaaaaaaaaaaa. bla.
\\
\end{tabularx}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\end{document}
（我不确定您是否需要整个样式文件tikzpagelayers来实现相同的效果。）请参阅tplbegin和tplend。
其结果是；
转变的结果-0.1em如下；
答案3
更新：
经过几版之后，我觉得 OP 想要一些可以用 来完成的东西sidebyside tcolorbox。OP 说 SUBTITLE 可以是tcolorbox标题，左右段落宽度可以自动调整到其内容，就像我的例子一样，也可以调整到固定宽度。淡入淡出的线条是作为overlay所需长度（在本例中为框的总宽度）的选项绘制的。
\documentclass[a4paper]{article}
\usepackage[most]{tcolorbox}
\usepackage{lipsum}
\tcbset{
mysidebox/.style={
sidebyside,
sidebyside adapt=left,
sidebyside gap=5mm,
sidebyside align=top,
%
colback=white,
colbacktitle=white,
fonttitle=\scshape,
coltitle=black,
title=#1,
%
frame hidden,
lower separated=false,
enhanced,
overlay={\fill[left color=red, right color=white] (title.south west) rectangle ([yshift=-1pt]title.south east);},
%
boxrule=0pt,
boxsep=0pt,
left=0pt,
right=0pt,
bottom=0pt,
toptitle=1pt,
bottomtitle=1pt,
}
}
\begin{document}
\lipsum[1]
\tcbsidebyside[mysidebox=This is my title
]
{bla bla bla }{\lipsum[2]}
\tcbsidebyside[mysidebox=another subtitle
]
{bla bla bla bla bla bla }{\lipsum[2]}
\end{document}
上一个答案
像这样？
\PassOptionsToPackage{svgnames}{xcolor}
\documentclass[a4paper]{article}
\usepackage{tikz}
\newlength{\mycustomlength}
\settowidth\mycustomlength{abcdefghiblablab}
\usepackage{tabularx}
\newcommand{\subtitle}[1]{%
\begin{tikzpicture}
\node[font=\scshape, text=black, inner xsep=0pt, outer sep=0pt] (aux) {#1};
\shade[left color=red, right color=white] (aux.south west) rectangle ([yshift=-1pt]aux.south east);
\end{tikzpicture}}
\begin{document}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{tabularx}{\textwidth}{@{}*{1}{p{\mycustomlength}}*{1}{X}@{}} % sub-headings modification
\multicolumn{2}{@{}l}{\sbox0{\subtitle{Some Subtitle}\phantom{M}}\usebox0 \tikz[baseline=-0.5ex] \shade[left color=red, right color=white] (0,0) rectangle ({\linewidth-\wd0},-0.02);}
\\
bla bla bla bla! & blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla. blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla.blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla.blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla.
\\
\multicolumn{2}{@{}l}{\sbox0{\subtitle{Another Subtitle}\phantom{M}}\usebox0 \tikz[baseline=-0.5ex] \shade[left color=red, right color=white] (0,0) rectangle ({\linewidth-\wd0},-0.02);}
\\
bla bla bla bla! & blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla. blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla.blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla.blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla.
\\
\multicolumn{2}{@{}l}{\sbox0{\subtitle{And A Third Subtitle}\phantom{M}}\usebox0 \tikz[baseline=-0.5ex] \shade[left color=red, right color=white] (0,0) rectangle ({\linewidth-\wd0},-0.02);}
\\
bla bla bla bla! & blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla. blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla.blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla.blaaaaaaaaaaaaa blaaaaaaaaaaaaaaa. bla.
\\
\end{tabularx}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\end{document}