There were two problems here:
1) Our chart model expects the char formatting of a data label as direct
formatting, so in case <c:dLbl> has no such formatting, but <c:dLbls>
has, oox has to explicitly inherit.
2) The data label char formatting is represented using
chart::FormattedString, but the char format of it is not (yet) exported
to ODF. Given that the char format of the series and the individual data
labels is the same, restore the same formatting on import to please
rendering.
With these, finally the chart labels in the bugdoc are white, not black
(and have a dark background, so they are readable).
Change-Id: Iebac5ce0be31a59bafb0f9fe7636330585e33822
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/98770
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>
Tested-by: Jenkins
8a43bfeffa