<h3 dir="auto">Bug report</h3>
<p dir="auto"><strong>Markers appear smeared and not clear</strong></p>
<ul dir="auto">
<li>When I plot markers with pyplot they show compression artifacts even when I save them as PNG.</li>
</ul>
<p dir="auto"><strong>Code for reproduction</strong></p>
<div class="highlight highlight-source-python notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="#!/usr/bin/env python                                                          

import numpy as np
import matplotlib.pyplot as plt

x = [1, 2, 3]

plt.errorbar(x, x, xerr=.05, yerr=.02, fmt='+')

plt.savefig('test.png')"><pre class="notranslate"><span class="pl-c">#!/usr/bin/env python                                                          </span>

<span class="pl-k">import</span> <span class="pl-s1">numpy</span> <span class="pl-k">as</span> <span class="pl-s1">np</span>
<span class="pl-k">import</span> <span class="pl-s1">matplotlib</span>.<span class="pl-s1">pyplot</span> <span class="pl-k">as</span> <span class="pl-s1">plt</span>

<span class="pl-s1">x</span> <span class="pl-c1">=</span> [<span class="pl-c1">1</span>, <span class="pl-c1">2</span>, <span class="pl-c1">3</span>]

<span class="pl-s1">plt</span>.<span class="pl-en">errorbar</span>(<span class="pl-s1">x</span>, <span class="pl-s1">x</span>, <span class="pl-s1">xerr</span><span class="pl-c1">=</span><span class="pl-c1">.05</span>, <span class="pl-s1">yerr</span><span class="pl-c1">=</span><span class="pl-c1">.02</span>, <span class="pl-s1">fmt</span><span class="pl-c1">=</span><span class="pl-s">'+'</span>)

<span class="pl-s1">plt</span>.<span class="pl-en">savefig</span>(<span class="pl-s">'test.png'</span>)</pre></div>
<p dir="auto"><strong>Actual outcome</strong></p>
<p dir="auto">See image attached.</p>
<p dir="auto"><strong>Expected outcome</strong></p>
<p dir="auto">I want markers without smearing or interpolation as clear as the resolution permits.</p>
<p dir="auto"><strong>Matplotlib version</strong></p>
<ul dir="auto">
<li>Matplotlib version 2.0.0, Python 2.7.13 and Debian 9.</li>
<li>Matplotlib installed with <code class="notranslate">pip</code></li>
</ul>
<p dir="auto"><a target="_blank" rel="noopener noreferrer nofollow" href="https://cloud.githubusercontent.com/assets/1030293/23870396/909af9d2-0826-11e7-92e9-3c583b1d692d.gif"><img src="https://cloud.githubusercontent.com/assets/1030293/23870396/909af9d2-0826-11e7-92e9-3c583b1d692d.gif" alt="test" data-animated-image="" style="max-width: 100%;"></a></p>
<p dir="auto">Using <code class="notranslate">errorbar</code> does not properly center the errorbar on the marker.  See the following example and output.  The issue persists in the legend as well.  The errorbar is a few pixels off center and changing the <code class="notranslate">linewidth</code> does not solve the issue.  <code class="notranslate">snap</code> kwarg has no effect either.  I have reproduced this using matplotlib 1.2.1 and 1.3.1 on Mac OSX 10.8.4.</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="import matplotlib.pyplot as plt
plt.errorbar([1],[1],[0.1],fmt='k^',capsize=5,capthick=2,ms=9,markerfacecolor='none',mew=2)
plt.show()"><pre class="notranslate"><code class="notranslate">import matplotlib.pyplot as plt
plt.errorbar([1],[1],[0.1],fmt='k^',capsize=5,capthick=2,ms=9,markerfacecolor='none',mew=2)
plt.show()
</code></pre></div>
<p dir="auto"><a target="_blank" rel="noopener noreferrer nofollow" href="https://cloud.githubusercontent.com/assets/8526633/4016780/7d8508ca-2a38-11e4-9d51-c406f5804024.png"><img src="https://cloud.githubusercontent.com/assets/8526633/4016780/7d8508ca-2a38-11e4-9d51-c406f5804024.png" alt="errorbar" style="max-width: 100%;"></a><br>
<a target="_blank" rel="noopener noreferrer nofollow" href="https://cloud.githubusercontent.com/assets/8526633/4016782/8118c4a4-2a38-11e4-8904-12e87f85e013.png"><img src="https://cloud.githubusercontent.com/assets/8526633/4016782/8118c4a4-2a38-11e4-8904-12e87f85e013.png" alt="legend" style="max-width: 100%;"></a></p>