scalebox / resizebox shifts fraction component

Question

I have the following code in my document:

$$ \frac{\displaystyle \sum_i \min(A_i,B_i)}
        {\displaystyle \sum_i \max(A_i,B_i)} $$

resulting in:

I prefer "display style" here, but the size of the contents in the numerator and denominator are a bit too large for my liking in the context where they appear, so I decided to scale down.

$$ \frac{\scalebox{0.75}{\text{$\displaystyle \sum_i \min(A_i,B_i)$}}}
        {\scalebox{0.75}{\text{$\displaystyle \sum_i \max(A_i,B_i)$}}} $$

but for some reason, this causes an unwanted shift:

so I'm forced to go back to standard "text style" mode in the meantime...

I can't spot why this might be happening based on the code above; I've also tried resizebox but it has the same issue ... has anyone got any idea why it's happening or how I could fix it?

(EDIT: I solved my particular problem by scaling down the fraction as a whole rather than its constituent parts; but the question remains. Is this a latex bug? Thanks.)

You probably want \frac{\sum\limits_i \min(A_i,B_i)}{\sum\limits_i \max(A_i,B_i)}. — egreg, Sep 05 '16 at 14:06
fair enough, thanks for the link; \[ ... \] is irrelevant here though. — Tasos Papastylianou, Sep 05 '16 at 15:43

score 5 · Answer 1 · answered Sep 05 '16 at 14:32

5

can you try this:

\documentclass{article}
\usepackage{graphicx}
\makeatletter
\long\def\Gscale@box#1[#2]#3{%
  \leavevmode
  \hbox\bgroup%<<<<<<<<
  \def\Gscale@x{#1}\def\Gscale@y{#2}%
  \setbox\z@\hbox{{#3}}%
  \setbox\tw@\hbox{\Gscale@start\rlap{\copy\z@}\Gscale@end}%
  \ifdim#2\p@<\z@
    \ht\tw@-#2\dp\z@
    \dp\tw@-#2\ht\z@
  \else
    \ht\tw@#2\ht\z@
    \dp\tw@#2\dp\z@
  \fi
  \ifdim#1\p@<\z@
    \hb@xt@-#1\wd\z@{\kern-#1\wd\z@\box\tw@\hss}%
  \else
    \wd\tw@#1\wd\z@
    \box\tw@
  \fi
  \egroup%<<<<<<<<
}

\begin{document}

\[
\frac{\scalebox{0.75}{$\displaystyle \sum_i \min(A_i,B_i)$}}
     {\scalebox{0.75}{$\displaystyle \sum_i \max(A_i,B_i)$}}
\]
\end{document}

answered Sep 05 '16 at 14:32

David Carlisle

757,742

This indeed fixes the odd behaviour, though I will admit it's a bit beyond my TeX skills so I don't quite follow it :) I decided to accept egreg's answer instead since that addresses my problem a bit more intuitively, but thank you for this answer! – Tasos Papastylianou Sep 05 '16 at 16:11
@TasosPapastylianou see http://chat.stackexchange.com/transcript/message/32124111#32124111 :-) – David Carlisle Sep 05 '16 at 16:12
ahahahah. I'm sorry I'm sorry I'm sorry xD – Tasos Papastylianou Sep 05 '16 at 16:28
1

@TasosPapastylianou I'll add the above fix to graphics at the next release, so then the extra box in the document as in egreg's version won't be needed (but won't do any harm) – David Carlisle Sep 05 '16 at 16:31
Glad to hear it! For the record, I don't know if this makes you more or less grumpy, hahah, but I used neither solution since I already 'solved' my problem as described in my edited question :p Glad to hear my question ended up being of some use though! – Tasos Papastylianou Sep 05 '16 at 16:33

score 4 · Accepted Answer · answered Sep 05 '16 at 14:35

In my opinion you don't really want \displaystyle, but neither you want \scalebox.

The size of \min and the other letters is right, it's just the summation symbol that grow too large:

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\[
\frac{\sum\limits_i \min(A_i,B_i)}
     {\sum\limits_i \max(A_i,B_i)}
\qquad
\frac{\displaystyle\sum_i \min(A_i,B_i)}
     {\displaystyle\sum_i \max(A_i,B_i)}
\]
\end{document}

If you really want to go the \scalebox way, enclose them in \mbox:

\documentclass{article}
\usepackage{amsmath}
\usepackage{graphicx}
\begin{document}
\[
\frac{\mbox{\scalebox{0.75}{$\displaystyle \sum_i \min(A_i,B_i)$}}}
     {\mbox{\scalebox{0.75}{$\displaystyle \sum_i \max(A_i,B_i)$}}}
\]
\end{document}

The issue is apparently due to how TeX typesets fractions, putting aside the numerator until it decides the size; the assignments performed by \scalebox get wrong without this further level of boxing.

Or, maybe better, use \mfrac from the nccmath package:

\documentclass{article}
\usepackage{amsmath}
\usepackage{nccmath}
\begin{document}
\[
\mfrac{\displaystyle \sum_i \min(A_i,B_i)}
      {\displaystyle \sum_i \max(A_i,B_i)}
\qquad
\frac{\displaystyle \sum_i \min(A_i,B_i)}
      {\displaystyle \sum_i \max(A_i,B_i)}
\]
\end{document}

All excellent suggestions, and good explanation. Thank you very much. — Tasos Papastylianou, Sep 05 '16 at 16:07

scalebox / resizebox shifts fraction component

2 Answers2

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