Text Formatting ⇒ Faking Height of one Expression with another

[ghostanime2001]

I know there is a command to fake the width of one expression with another expression using the \makebox* command from "makebox" package. But is there also another command to fake the height of one expression with another expression ?

[5gon12eder]

You may use the plain TeX macros \smash and \vphantom to achieve this. In the following example, in the first paragraph, the height of the huge word ``line'' is smashed to zero. In the second paragraph, the second line consumes the same height as if the word ``line'' would be there in \huge font.

Code: Select all

\documentclass{article}

\begin{document}
  \noindent%
  This is a line of text.\\
  This is a \smash{\huge line} of text.\\
  This is a line of text.
  
  \vspace{5ex}
  
  \noindent%
  This is a line of text.\\
  This is a\vphantom{\huge line} of text.\\
  This is a line of text.

\end{document}

demo.png (12.83 KiB) Viewed 6800 times

Equipped with this, you can define the macro \fakeheight that typesets its first argument as if it had the height from the second.

Code: Select all

\newcommand{\fakeheight}[2]{\mbox{\smash{#1}\vphantom{#2}}}

The whole story is very nicely described in a TGUBoat article by Alexander R. Perlis.

[ghostanime2001]

When I try to use the \fakeheight command on chemical formula's the positioning of the superscript (+) charge moves upwards from the original positioning in the original table. How can I prevent this from happening ?

Code: Select all

    \documentclass{article}
    \usepackage[version=3]{mhchem}
    \usepackage{tikz}
    \usepackage{makebox}
    \usepackage{nccboxes}
    \usetikzlibrary{matrix,calc}
\newcommand{\fk}[2]{\mbox{\smash[t]{#1}\vphantom{#2}}}
\begin{document}
Original: \begin{tikzpicture}
\matrix (m) [matrix of math nodes,ampersand replacement=\&,nodes=draw]
{
\vphantom{\ce{H2S <=>}} \& \node (a) {\ce{H2S <=>}}; \& \node (b) {\ce{H+ +}}; \& \node (c) {\ce{HS-}}; \\ \hline
a \& \node {b}; \& \node {c}; \& \node {d}; \\
a \& \node {b}; \& \node {c}; \& \node {d}; \\
a \& \node {b}; \& \node {c}; \& \node {d}; \\
};
\end{tikzpicture} \\ \\ 
Now look at the negative charge on \ce{H+} and \ce{HS-} \\
\begin{tikzpicture}
\matrix (m) [matrix of math nodes,ampersand replacement=\&,nodes=draw]
{
\& \node (a) {\fk{\ce{H2S <=>}}{\ce{HS-}}}; \& \node (b) {\fk{\ce{H+ +}}{\ce{HS-}}}; \& \node (c) {\fk{\ce{HS-}}{\ce{HS-}}}; \\ \hline
a \& \node {b}; \& \node {c}; \& \node {d}; \\
a \& \node {b}; \& \node {c}; \& \node {d}; \\
a \& \node {b}; \& \node {c}; \& \node {d}; \\
};
\end{tikzpicture}
\end{document}

[5gon12eder]

How can I prevent this from happening ?

Don't fake a different height but let TeX' positioning algorithms know the actual dimensions of the objects to arrange.

[ghostanime2001]

There's nothing I can do ???