In Draw, insert a circle shape. Copy, paste as metafile into Writer document.
Change anchor mode to "as character" -> no anti-aliasing anymore. Change back to
"at paragraph" -> anti-aliasing works again.
Created attachment 42775 [details]
Fixed by your patch sent to the mailing list and pushed to 3.4 branch.
You should attach yours test files (like antialiasing-metafile-test.odt with the equations) to this bug report.
Big thanks for your patches :-)
Created attachment 48152 [details]
Anti-aliasing of a metafile object
Created attachment 48153 [details]
Anti-aliasing of a draw8 object
Assignee due to facts