> Perhaps the following? > (1) If glyph A is in the 'cmap' table, and glyph B is not, prefer > glyph A. > (2) If one glyph needs X lookups and another glyph needs Y, and X < Y, > prefer glyph X. > I'm not sure whether (2) makes sense, though. > Can you give one or more examples for such cases?
To repeat what I said in an email that I accidentally didn't send to the mailing list: > I simply noticed that it's possible for 2 characters to map to the same glyph, which means that a glyph would map to 2 characters. I don't have any examples in mind for when this would actually happen. I was planning on either ignoring the situation to let it be resolved arbitrarily, or removing both entries. The situation is resolved arbitrarily for now. I want to have a reason for the rule that I choose before I choose a rule for such cases. (1) seems to generally make sense because the cmap table is more "direct". Also: what else needs to be done for the project to be complete and ready to become a part of freetype? The remaining tasks I can think of are: - Fill in, or find someone to fill in the rest of the adjustment database. - properly address the 'salt' table and similar cases in the glyph alternative finding algorithm. - Test everything more thoroughly. At this point, I know that the segment removal + vertical stretch is definitely the best approach, and the latest commit applies that to all the characters with tildes rather than a comparison of approaches. I previously thought that it caused some regressions, but I now know that the examples I had were just preexisting quirks in either the font or the autohinter. > To help people understand the non-trivial algorithm I > suggest that you add a big comment that shows it working step by step > for an example font, using a reduced set of features and glyphs. This comment has been added. On Tue, Oct 3, 2023 at 7:04 AM Werner LEMBERG <w...@gnu.org> wrote: > > > OK. I think it is a bad side effect of the current auto-hinting > > > algorithm that there are different approaches. > > > > I just want to clarify: you understood that the reason I used > > different approaches for each letter was to compare the approaches? > > My intent is to use one of those approaches as a universal algorithm > > for all characters with tildes. So every character would just have > > a boolean flag for whether to apply tilde hinting or not. > > Ah, I was confused, sorry – I thought that you get such varying > results for a single algorithm. Sometimes it happens (not taking your > current work into account) that blue zones affect the hinting of > accents in a bad way, and I thought this were such cases. > > > Also, did you see my question about a glyph mapping to multiple > > characters? > > I missed it, sorry again. You write: > > > It's possible that 2 characters in the adjustment database could map > > to the same glyph, which will create 2 entries in the reverse > > character map with the same glyph as a key. In this case, the > > character that glyph maps to is decided arbitrarily based on which > > one the binary search chooses and which order qsort puts them in. > > What should be done in these cases? > > Perhaps the following? > > (1) If glyph A is in the 'cmap' table, and glyph B is not, prefer > glyph A. > > (2) If one glyph needs X lookups and another glyph needs Y, and X < Y, > prefer glyph X. > > I'm not sure whether (2) makes sense, though. > > Can you give one or more examples for such cases? > > > Werner >
