The method PDFIProcessor::mirrorString() was removed, and
::comphelper::string::reverseString was used, by Kevin Suo in commit
69e9925ded.
The old PDFIProcessor::mirrorString() did two things:
1) Reverse the code points in the string. However, due to its use of iterateCodePoints(&i)
rather than iterateCodePoints(&i, -1) (i.e. iterating in forward rather than reversed order),
the reverse was not functioning at all.
2) Use GetMirroredChar (i.e. the icu unicode u_charMirror() which was dropped in
commit 720a093461) to get the mirrored-image of
characters with the Bidi_Mirrored properties.
Stephan Bergmann restored the #1 in commit 50d73574b6
(by introducing comphelper::string::reverseCodePoints). However, the #2 was not restored.
I do not see a clear reason to drop #2 (at least this is an area I don't quite familiar
with), so it's better to restore it as well, in *this* commit, named as SubstituteBidiMirrored.
Change-Id: Ic263097938310e6e04f3b95bb12e4f4e834198f2
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/143041
Tested-by: Jenkins
Reviewed-by: Kevin Suo <suokunlong@126.com>