As reported in bug 116672, text in flipped/rotated shapes are always upside down. For a general solution we need the ability to rotate text to any degree. Similar issue regarding forms was reported in bug 115591.
(In reply to Regina Henschel from comment #8)
> Yes, ODF has the feature to rotate the text. But there are two shortcomings:
> 1. LibreOffice has no UI for this feature.
> 2. Import and Export with MS Office does not work. LibreOffice cannot yet
> read/write the OOXML text rotations needed for 180° rotation and MS Office
> cannot read/write the ODF text rotations.
> MS Office has the trapezoid, with the smaller top edge in its presets, not
> the one with the smaller edge at bottom, which is currently in LibreOffic's
> preset. I don't know why LibreOffice has it, perhaps it was used in MS 97.
> If you use LibreOffice's trapezoid or my trapezoid from the attached file
> and save to pptx, it has no handle, if you open it in PowerPoint. If saved
> to odp, PowerPoint opens it and it has the handle. But if then saved to pptx
> by PowerPoint and opened by LibreOffice, the handle is not usable.
> If LibreOffice opens a pptx file, it generates a shape of type
> "ooxml-trapezoid" with smaller edge at top. If you use this shape in a new
> file, which is then exported into the pptx-format, PowerPoint can read it.
> But if you use it in a new file and save to odp-format, it has at least the
> viewBox bug 76334. PowerPoint will not open it.
> Simple adding the trapezoid from my attached file to the preset might be a
> _immediately_ possible solution. All other solutions need a lot of bug
> fixing and/or feature implementation.
> I have not tested Word or Excel. There might be additional problems.
Created attachment 147462 [details]
To be clear, "only" the UI is missing. LibreOffice has already internally the ability to rotate text in a custom shape. Open attached document to see it.