<html>
<head>
<base href="https://bugs.freedesktop.org/" />
</head>
<body><span class="vcard"><a class="email" href="mailto:psychon@znc.in" title="Uli Schlachter <psychon@znc.in>"> <span class="fn">Uli Schlachter</span></a>
</span> changed
<a class="bz_bug_link
bz_status_NEEDINFO "
title="NEEDINFO --- - Line drawing not thread-safe"
href="https://bugs.freedesktop.org/show_bug.cgi?id=74355">bug 74355</a>
<br>
<table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>What</th>
<th>Removed</th>
<th>Added</th>
</tr>
<tr>
<td style="text-align:right;">Status</td>
<td>NEW
</td>
<td>NEEDINFO
</td>
</tr></table>
<p>
<div>
<b><a class="bz_bug_link
bz_status_NEEDINFO "
title="NEEDINFO --- - Line drawing not thread-safe"
href="https://bugs.freedesktop.org/show_bug.cgi?id=74355#c1">Comment # 1</a>
on <a class="bz_bug_link
bz_status_NEEDINFO "
title="NEEDINFO --- - Line drawing not thread-safe"
href="https://bugs.freedesktop.org/show_bug.cgi?id=74355">bug 74355</a>
from <span class="vcard"><a class="email" href="mailto:psychon@znc.in" title="Uli Schlachter <psychon@znc.in>"> <span class="fn">Uli Schlachter</span></a>
</span></b>
<pre>(In reply to <a href="show_bug.cgi?id=74355#c0">comment #0</a>)
<span class="quote">> 1. share a single cairo_surface_t between the threads, and have each thread
> draw using its own cairo_t. This crashes, but maybe I'm hoping for too much
> (although an image surface is essentially just a big array of bytes that
> should be writable from multiple threads). </span >
Sure, just an array. And this works as long as you expect anything like useful
results. Cairo is supposed to be thread-safe as long as the threads don't share
any state (well, this is an oversimplification, but your first approach isn't
supposed to work).
<span class="quote">> 2. create a cairo_surface_t and cairo_t for each thread, and merge the
> results after drawing has completed. This crashes in pixman. The only Cairo
> calls that happen on a per-thread basis are cairo_set_line_cap,
> cairo_set_source_rgba, cairo_set_line_width, cairo_set_dash, cairo_move_to,
> cairo_line_to, and cairo_stroke.</span >
Since this is so simple, do you have some small, self-contained C code that
only depends on some threading API and cairo and that reproduces this problem?</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are the QA Contact for the bug.</li>
</ul>
</body>
</html>