MCGR: Use BGradient in export of Fontwork to docx too

Transparency values are not exactly like in UI because converting
through rgb-color adds rounding inaccuracy. The unit tests are adjusted
accordingly. With only start and end values it was possible to use the
UI values directly. It would be possible to make special cases for
front and back value, but I think it is not worth the effort.

The previous solution had the error, that the stops were not mirrored
in case of non linear gradient. That is corrected now. The unit tests
are adjusted.

The previous solution had assumed that our 'intensity' at start or end
colors is the same as the 'lumMod' attribute in OOXML. However, this is
not the case. So now the 'intensity' is incorporated into the color.
Again, the unit tests are adjusted.

Change-Id: Id02e455dc09d12c5b453637fcb2bdc4f8f1529d1
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/152839
Tested-by: Jenkins
Reviewed-by: Regina Henschel <rb.henschel@t-online.de>
(cherry picked from commit 0028c2311ca14669ca530cd4db422cd3cf9438ca)
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/153019
Reviewed-by: Xisco Fauli <xiscofauli@libreoffice.org>

0 files changed, 0 insertions, 0 deletions