调试 - 数学模式下的间距

Question

这是一个相当复杂的解决方案，它根本不会影响任何间距（水平或垂直）。\vrule您可以存储想要打印的坐标，然后在发货前（即实际创建页面时）在此位置打印，而不是立即打印。

以下代码需要运行两次才能运行，我已经使用 LaTeX、pdfLaTeX、LuaLaTeX 和 XeLaTeX 对其进行了测试。\begin{document}和之间的部分\end{document}与您的代码相同，只是我将其替换\mathrlap{\smash{...}}为\printlater{...}。

^{（此代码似乎与standalone类不兼容，可能是因为\paperheight不是实际的纸张高度。）}

%\documentclass[varwidth=3cm,margin=2mm]{standalone} %% <- does not work, not sure why
\documentclass[a4paper]{article} %% <- paper size option is important!

\usepackage{amsmath} 
%% ^ remove \ifmeasuring@\else and \fi below if you don't use amsmath
% \usepackage{mathtools} %% <- not needed
\usepackage{xcolor}

\AtBeginDocument{%
    \abovedisplayskip=0pt%12pt plus 3pt minus 9pt
    \abovedisplayshortskip=0pt%0pt plus 3pt
    \belowdisplayskip=0pt%12pt plus 3pt minus 9pt
    \belowdisplayshortskip=0pt%7pt plus 3pt minus 4pt
}

\usepackage{atbegshi} %% <- for \AtBeginShipout and \AtBeginShipoutUpperLeft

\makeatletter %% <- change @ so that it can be used in command names

  \@ifundefined{savepos}
  {  %% <- For pdflatex and xelatex
    \let\savepos\pdfsavepos
    \let\lastxpos\pdflastxpos
    \let\lastypos\pdflastypos
  }{} %% <- For lualatex
  \newcounter{printlatercounter} %% <- unique ids for things we want to print later
  \newcommand*\printlater[1]{%
    \ifmeasuring@\else %% <- Do nothing if in amsmath's "measuring" mode
      \stepcounter{printlatercounter}%
      \expandafter\printlater@writepos\expandafter{\number\c@printlatercounter}%
      \expandafter\printlater@printnow\expandafter{\number\c@printlatercounter}{#1}%
    \fi
  }
  \newcommand*\printlater@writepos[1]{% %% <- Writes the current coordinates to the aux file
    \savepos %% <- get current position on page
    \write\@auxout{\global\string\@namedef{printlater@anchorx@#1}{\the\lastxpos}}% %% <- write x coord.
    \write\@auxout{\global\string\@namedef{printlater@anchory@#1}{\the\lastypos}}% %% <- write y coord.
  }
  \newcommand*\printlater@printnow[2]{% %% <- Prints #2 at the #1-th set of coordinates
    \@ifundefined{printlater@anchorx@#1}{}{% %% <- test if the coordinates are set
      \AtBeginShipoutNext{% %% <- execute just before shipout
        \AtBeginShipoutUpperLeft{% %% <- insert things at the top left corner of the page
          \setlength{\unitlength}{1sp}% %% <- coordinates are in sp (65536sp = 1pt)
          \put(\@nameuse{printlater@anchorx@#1},\the\numexpr\@nameuse{printlater@anchory@#1}-\paperheight){#2}%
        }%
      }%
    }%
  }

\makeatother %% <- return @ to normal

\begin{document}

\begin{align*} % two plain \printlaters (red)
    \Phi = \printlater{\color{red}\vrule depth 5pt height 10pt width .2pt}\sum
    \printlater{\color{red}\vrule depth 20pt height 10pt width .2pt}
\end{align*}

\begin{align*} % one plain \printlater (orange)
    \Phi = \sum
    \printlater{\color{orange}\vrule depth 20pt height 10pt width .2pt}
\end{align*}

\begin{align*} % target spacing (untouched)
    \Phi = \sum
\end{align*}

\begin{align*} % one \printlater in the beginning (green)
    \printlater{\color{green}\vrule depth 30pt height 80pt width .2pt}
    \Phi = \sum
\end{align*}

\begin{align*} % corrected \printlaters (blue)
    \Phi = \mathopen{\printlater{\color{blue}\vrule depth 5pt height 95pt width .2pt}}
    \sum
    \mathclose{\printlater{\color{blue}\vrule depth 5pt height 60pt width .2pt}}
\end{align*}

\end{document}

笔记：[a4paper]提供的选项很\documentclass重要，因为它可以确保\paperheight（我们需要的）值是正确的。默认情况下，\paperheight即使您正在制作 A4 文档，其值也为 279.4 毫米（信纸大小），这会导致所有规则偏移 297 毫米 - 279.4 毫米 = 17.6 毫米。（只有当xcolor包也被删除时才会发生这种情况，因为由于某种原因，加载此包也会改变的值\paperheight。）

我上面定义的宏\printlater接受一个参数，并在 shipout 之前将其打印在当前位置。它做了四件事

它首先使用来检查我们是否处于的amsmath“测量模式” \ifmeasuring@，如果是，则不执行任何操作。如果没有此检查，则\printlater每当在环境等内部使用的参数时，都会打印两次align。（参见这个问题。
它会增加printlatercounter，为我们想要打印的内容生成唯一的 ID。
\(pdf)savepos它使用和检索当前 x/y 坐标，\(pdf)last<x/y>pos并将它们作为写入辅助文件\printlater@anchor<x/y>@<id>。这些坐标以 sp（65536sp = 1pt）为单位，相对于页面的左下角。
如果printlater@x@<id>已定义（第二次运行时也是如此），它会指示 TeX 在传送页面之前打印参数。宏\AtBeginShipoutNext和\AtBeginShipoutUpperLeft来自atbegshi包裹处理此事。

之所以需要两次运行，是因为直到页面交付时才知道内容的确切坐标，而那时再打印其他内容就太晚了。但是，我们仍然可以将这些坐标写入辅助文件，然后在第二次运行时使用它们。

如果您想要手动移动其中一个\vrules，比如说.5pt向左移动，您可以在它前面加上一个\hskip-.5pt（在内\printlater）。

在 shipout 上绘制的内容目前在后台，在后面文本（您不会注意到，因为它没有触及任何文本）。这可能是可取的，但如果您希望它位于前台，您需要使用，\AtBeginShipoutUpperLeftForeground而不是\AtBeginShipoutUpperLeft，

您也可以使用 TikZ 来\put打印内容。您需要加载 TikZ 并使用：

\newcommand*\printlater@printnow[2]{%
  \@ifundefined{printlater@anchorx@#1}{}{%
    \AtBeginShipoutNext{%
      \AtBeginShipoutUpperLeftForeground{%
        \tikz[overlay,remember picture]
          \node[anchor=base]
            at ([xshift=\@nameuse{printlater@anchorx@#1}sp,
                 yshift=\@nameuse{printlater@anchory@#1}sp]current page.south west)
                   {\rlap{#2}};%
      }%
    }%
  }%
}

而不是先前的定义。我看不出你现在为什么要这么做，但如果你在某个时候决定要绘制比水平/垂直线更复杂的东西，那么知道这一点很有用。

编辑：这是另一个测试，它比较了原始的\colon、、和周围的间距。彩色线的位置是自动化的，灰线各自分开（从红线开始）。amsmath\colon:\mathpunct:\mathord:1pt

\documentclass[a4paper]{article} %% <- paper size option is important!

\let\oldcolon\colon
\usepackage{amsmath}
%% ^ remove \ifmeasuring@\else and \fi below if you don't use amsmath
\let\amsmathcolon\colon

\usepackage{xcolor}

\usepackage{atbegshi} %% <- for \AtBeginShipout and \AtBeginShipoutUpperLeft

\makeatletter %% <- change @ so that it can be used in command names
  \@ifundefined{savepos}
  {  %% <- For pdflatex and xelatex
    \let\savepos\pdfsavepos
    \let\lastxpos\pdflastxpos
    \let\lastypos\pdflastypos
  }{} %% <- For lualatex
  \newcounter{printlatercounter} %% <- unique ids for things we want to print later
  \newcommand*\printlater[1]{%
    \ifmeasuring@\else %% <- Do nothing if in amsmath's "measuring" mode
      \stepcounter{printlatercounter}%
      \expandafter\printlater@writepos\expandafter{\number\c@printlatercounter}%
      \expandafter\printlater@printnow\expandafter{\number\c@printlatercounter}{#1}%
    \fi
  }
  \newcommand*\printlater@writepos[1]{% %% <- Writes the current coordinates to the aux file
    \savepos %% <- get current position on page
    \write\@auxout{\global\string\@namedef{printlater@anchorx@#1}{\the\lastxpos}}% %% <- write x coord.
    \write\@auxout{\global\string\@namedef{printlater@anchory@#1}{\the\lastypos}}% %% <- write y coord.
  }
  \newcommand*\printlater@printnow[2]{% %% <- Prints #2 at the #1-th set of coordinates
    \@ifundefined{printlater@anchorx@#1}{}{% %% <- test if the coordinates are set
      \AtBeginShipoutNext{% %% <- execute just before shipout
        \AtBeginShipoutUpperLeft{% %% <- insert things at the top left corner of the page
          \setlength{\unitlength}{1sp}% %% <- coordinates are in sp (65536sp = 1pt)
          \put(\@nameuse{printlater@anchorx@#1},\the\numexpr\@nameuse{printlater@anchory@#1}-\paperheight){#2}%
        }%
      }%
    }%
  }
\makeatother %% <- return @ to normal

\begin{document}

\newcommand*\myrule[2][0pt]{\printlater{\hskip#1\color{#2}\vrule depth 5pt height 10pt width .2pt}}
\newcommand*\grayrules{\myrule[1pt]{gray}\myrule[2pt]{gray!50!white}\myrule[3pt]{gray!25!white}\myrule[4pt]{gray!12.5!white}}

\begin{align*}
    f\myrule{red}\grayrules\oldcolon \myrule{green}{\myrule{blue}X} &\to Y
\\
    f\myrule{red}\grayrules\amsmathcolon \myrule{green} {\myrule{blue}X} &\to Y
\\
    f\myrule{red}\grayrules: \myrule{green} {\myrule{blue}X} &\to Y
\\
    f\myrule{red}\grayrules\mathpunct: \myrule{green} {\myrule{blue}X} &\to Y
\\
    f\myrule{red}\grayrules\mathord: \myrule{green} {\myrule{blue}X} &\to Y
\end{align*}

\end{document}

编辑：添加了关于该选项必要性的评论a4paper并修复了重复打印问题。感谢@nox 指出这些问题。

Answer 1