# Cases environment discontinuous line in brace [closed]

I have the following equation environment with cases:

\documentclass[preview,border=12pt]{standalone}

\usepackage{amsmath}

\begin{document}
\begin{equation*}
\operatorname{atan2}(y,x) := \begin{cases}
\arctan\frac{y}{x} & \mathrm{if}\ x > 0\\
\arctan\frac{y}{x} + \pi & \mathrm{if}\ x < 0,\ y \geq 0\\
\arctan\frac{y}{x} - \pi & \mathrm{if}\ x < 0,\ y < 0\\
+\pi/2 & \mathrm{if}\ x = 0,\ y > 0\\
-\pi/2 & \mathrm{if}\ x = 0,\ y < 0\\
0 & \mathrm{if}\ x = 0,\ y = 0
\end{cases}
\end{equation*}
\end{document}


For some reason, the line of the brace is weirdly dotted:

How can I get a nice continuous line there?

Update:

Update #2:

After zooming in even more, I just realized that the symbols which build the brace are pixelated instead of being smooth vectors like all other font glyphs. What could be the reason for this?

-
What viewer are you using? A minimal working example (MWE) in article with just amsmath shows a clean and continuous brace in Adobe. – Werner Jul 13 '12 at 2:54
The same as what Werner said, I also got a perfect output, no weird brace. – Click Me Jul 13 '12 at 3:15
I have seen this problem before (but not quote this bad), and it was a problem with the viewer. Viewing it with Adobe Acrobat and zoning in showed a continuous brace. – Peter Grill Jul 13 '12 at 3:35
The issue was just with the viewer. With your current MWE I see 5 breaks when viewed with the TeXWorks PDF viewer. With Acrobat (V 10.1.3 on Mac) I do see one break at 400%, but none at 800%. – Peter Grill Jul 13 '12 at 4:04
Make sure you make a copy of it first. – Click Me Jul 13 '12 at 4:13

## closed as too localized by Werner, egreg, lockstep, Marco Daniel, percusseJul 18 '12 at 10:23

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