length/bounding box of open butt cap lines too large

[Jaspervdg]

If you select an open line, the length that's reported
by InkScape is too large. A simple demo is something
like this:
<svg width="100mm" height="100mm" viewBox="0 0 100 100"
version="1.1">
  <g fill="none" stroke="black" stroke-width="2" >
    <line x1="1" y1="0" x2="1" y2="100" />
  </g>
</svg>
InkScape will say the line is 2mm wide (InkScape
includes the stroke width, which is fine here) and
102mm high, which is 2mm too high.
I got the following response on the mailinglist (by
"bulia byak"):
<quote>
It's a bug. Lines' bboxes extend beyond line ends by
the line width.
This is because the bbox is now calculated simply by
adding half the
stroke width to all 4 sides of the without-stroke bbox,
but in this
case (for unclosed horizontal line) it should be added
only to the top
and bottom. It is a very difficult bug to fix because
we currently
have no code to reliably determine how far the stroke
of a given shape
extends, which may be affected not only by stroke width
but also by
(as in your case) shape orientation and closeness, join
and cap types,
and miter limit.
</quote>

[Buliabyak-users (buliabyak-users)]

Raising priority because this makes it impossible to do
pattern fill with lines without gaps.

[Peter Moulder (pjrm)]

Re pattern fill: the workaround is to change line cap to square.
(Leaving priority unchanged.)

[Peter Moulder (pjrm)]

The simplest implementation would be to use stroke-to-path
(sp_selected_path_outline in splivarot.cpp) and take bbox of
the result. Would require splitting out the relevant bits
of sp_selected_path_outline.

[su_v (suv-lp)]

Fix committed in r10589 with the removal of libnr, see
<http://article.gmane.org/gmane.comp.graphics.inkscape.devel/37154>