Comment 1 for bug 166252

The squares are aligned exactly. The "gaps" are a rendering
artefact caused by the fact that the edges are antialiased.
These "gaps" therefore depend on zoom level. I don't know if
this is fixable at all without removing AA, at least I don't
know of any vector editor or viewer with antialiased display
that would not have this problem. For example your file is
displayed with similar gaps by both Adobe SVG viewer and
Batik. Xara and Illustrator also have this same problem.

In any case, this is a dupe of

http://sourceforge.net/tracker/index.php?func=detail&aid=1003049&group_id=93438&atid=604309

which will be closed when we have a non-AA rendering mode.