Created attachment 179649 [details]
Illustration of the problem

This is a follow up to bug 148501.
The shapes "Octagon Bevel" and "Diamond Bevel" use shadings which cannot be expressed in OOXML and which are darker than those originally introduced in OOo2.1. The attachment here has a copy of the screenshots of attachment 179647 [details].

My request is to use similar shapes, which are nearer to the original intended shading and are better suitable for export to OOXML.

The attachment has two proposals:
(My favorite) Use the darken/lighten commands of the enhanced-path. They are available in API. They are not available in ODF 1.3 and need to be written in drawooo namespace. Their export as static shape (no handles) works already including shading. Problem is that the shading does not work together with bitmap-filling. That is a problem in LO, PowerPoint shows the shading in those cases.

The other way would be to use a color shade encoding, which gives the desired shading but is restricted to values available in OOXML. That renders the shading for bitmap filling in LO. This color shade encoding does not belong to ODF, but is specific to LO and AOO, MS Office does not know it. The export to OOXML would need to convert it to the darken/lighten attribute of OOXML. But that does not exists yet.

Because the color encoding of OOo2.1 allows up to 14 values for shading, but OOXML has only 4 values, we would need to restrict the shades. Therefore there are two suggestions for the "Octagon Bevel", which has original 5 shades in the outer segments.