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When using xrightarrow, I sometimes gets weird artifacts on the arrow: it looks like the arrow is somewhat "doubled" in the middle. But this only happens when zoomed out; when I zoom in very close, the artifact disappears. This happens with all the PS and PDF viewers that I've tried.

\documentclass{minimal}
\usepackage{amsmath}
\begin{document}
$\xrightarrow{\quad}$
\end{document}

Result (for SumatraPDF when compiled as a PDF, the results are similar if not identical for other viewers, PDF and PS alike):

arrow

Here I just put space to make the arrow longer, but it happens no matter what I put on the arrow. Is there a way around this issue, or an alternative to xrightarrow?

Najib Idrissi
  • 898
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    This is most likely due to pixel rounding errors in the PDF viewer. Note that the extension feature is made via overlaying two symbols. – daleif Oct 15 '14 at 09:11
  • @daleif As I mentioned, this happens (to some extent) in all the PDF viewers that I've tried: sumatrapdf, adobe reader, ps_viewer (which reads PDFs despite the name). – Najib Idrissi Oct 15 '14 at 09:14
  • It also happens for PS viewers (sumatra, ghostscript...). Unless all these viewers have, by coincidence, the same bug, I think it's a problem with the way this arrow is produced, not a bug of the viewer. – Najib Idrissi Oct 15 '14 at 09:36
  • The \xrightarrow generates a set of minus signs (by \cleaders) followed by arrow. It is possible, that the arrow has different hinting data than the minus. These "hinting" are used for rasterizing at low screen resolution. Or the hinting algorithm does artifact itself when there are overlapping characters. – wipet Oct 16 '14 at 07:38

1 Answers1

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Well, compare with this

\documentclass{article}
\usepackage{amsmath}
%\usepackage[T1]{fontenc}
\usepackage{anyfontsize}
\begin{document}

\fontsize{4cm}{4cm}\selectfont

$\xrightarrow{\quad}$
\end{document}

no vissible bug.

daleif
  • 54,450
  • ...Yes there is still a bug, if you zoom out. https://i.imgur.com/J9YYFYH.png And anyway how is that a solution? It completely destroys the document. – Najib Idrissi Oct 15 '14 at 11:33
  • But it is still an artefact of the previewer. There is not much you can do about it other than try to change the font. It will not be detectable when printed on paper (because the resolution is much higher). – daleif Oct 15 '14 at 12:06
  • Are you saying that all viewers have, for some reason, the exact same bug? – Najib Idrissi Oct 15 '14 at 12:08
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    Again it is not a bug! See http://tex.stackexchange.com/questions/132279/distortions-caused-by-latex – daleif Oct 15 '14 at 12:08
  • Do you mean these artifacts are wanted behavior? – Najib Idrissi Oct 15 '14 at 16:15