Comment 2 for bug 808898

a) Issue with PDF export reproduced with Inkscape 0.48.1 on Mac OS X 10.5.8 (i386)

Problem: parent layer of masked group has a 'transform' attribute which is ignored/incorrectly compensated for the masked group.
  <g
     inkscape:label="Calque 1"
     inkscape:groupmode="layer"
     id="layer1"
     transform="translate(-352.85714,-166.29075)">

Workaround:
1) open in Inkscape
2) add a new layer
3) move both objects (masked group, filtered ellipse) to the new layer
4) save a copy as PDF

Related to or duplicate of
Bug #743053“Exporting mask with gradient to EPS results in blank page”

b) Complex mask (group of paths with complex filter effects) on a transformed group fails to be rendered in other SVG viewers:
Reproduced with rsvg-view (librsvg 2.34.0), Squiggle (Batik 1.7) Opera 11.5, Chromium 14.0.786.0 on Mac OS X 10.5.8 (i386)
Not sure, whether Inkscape's code is wrong, or other SVG renderers don't support the nested levels of transformed (translated) groups, e.g.

    <g
       id="g3289-4"
       transform="translate(837.14285,6.0714171)"
       mask="url(#mask3104)">

Possible workaround: reduce level of nested transforms:
1) Move masked object to new layer as described above.
2) Release the mask, ungroup the group with the stars and group it again (to get rid of the group transform attribute),
3) Reapply the mask

Now the image displays in Squiggle (Batik), Opera and Chromium the same way as it does in Inkscape. rsvg-view from librsvg 2.34.0 still fails, but I don't think that's an issue with Inkscape itself or its SVG code - librsvg, AFAIK also used for EOG, is known to support fewer SVG 1.1 features than e.g. Inkscape.