Ledger lines in PNG output have white interior

[Reinhold Kainhofer]

I'm using lilypond on Ubuntu oneiric (both self-compiled 2.15.30 as well 
as ubuntu's 2.12.3).

When converting  to PNG rather than PDF, all ledger lines show artefacts 
in that the interior of the ledger lines is white rather than black. 
Simply compile the attached file ledger-png.ly with the command line:

    lilypond --png -dpreview -dresolution=600 ledger-png.ly

(The output file ledger-png.preview.png is attached to this report, too).

The problem appears with 2.15.30 and with ubuntu's stock lilypond 2.12.3.

Cheers,
Reinhold

--
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Reinhold Kainhofer, address@hidden, http://reinhold.kainhofer.com/
 * Financial&  Actuarial Math., Vienna Univ. of Technology, Austria
 * http://www.fam.tuwien.ac.at/, DVR: 0005886
 * LilyPond, Music typesetting, http://www.lilypond.org

ledger-png.ly
Description: Text document

ledger-png.preview.png
Description: PNG image