Currently fonttools doesn't support merging when one of the inputs has different tables not present in the other. In the following example, NotoSans-Regular doesn't have vmtx.

pyftmerge --verbose NotoSansNandinagari-Regular.ttf  NotoSans-Regular.ttf
Merging 'cmap'.
Merged 'cmap'.
Merging 'GSUB'.
Merged 'GSUB'.
Merging 'GDEF'.
Merged 'GDEF'.
Merging 'head'.
Merged 'head'.
Merging 'cvt '.
Merged 'cvt '.
Merging 'gasp'.
Merged 'gasp'.
Merging 'DSIG'.
Don't know how to merge 'DSIG'.
Dropped 'DSIG'.
Merging 'loca'.
Merging 'vmtx'.
Traceback (most recent call last):
  File "/home/ubuntu/projects/go-noto-universal/venv_fonty/bin/pyftmerge", line 8, in <module>
    sys.exit(main())
  File "/home/ubuntu/projects/go-noto-universal/venv_fonty/lib/python3.8/site-packages/fontTools/misc/loggingTools.py", line 372, in wrapper
    return func(*args, **kwds)
  File "/home/ubuntu/projects/go-noto-universal/venv_fonty/lib/python3.8/site-packages/fontTools/merge.py", line 1276, in main
    font = merger.merge(fontfiles)
  File "/home/ubuntu/projects/go-noto-universal/venv_fonty/lib/python3.8/site-packages/fontTools/merge.py", line 1097, in merge
    table = clazz(tag).merge(self, tables)
  File "/home/ubuntu/projects/go-noto-universal/venv_fonty/lib/python3.8/site-packages/fontTools/merge.py", line 156, in merge
    return m.mergeObjects(self, self.mergeMap, tables)
  File "/home/ubuntu/projects/go-noto-universal/venv_fonty/lib/python3.8/site-packages/fontTools/merge.py", line 1154, in mergeObjects
    value = mergeLogic(getattr(table, key, NotImplemented) for table in tables)
  File "/home/ubuntu/projects/go-noto-universal/venv_fonty/lib/python3.8/site-packages/fontTools/merge.py", line 88, in sumDicts
    d.update(item)
TypeError: 'NotImplementedType' object is not iterable

Above is with fonttools 4.28.3

Latest CI builds create GoNotoContemporary.ttf which is a superset of all regional fonts (Asia + Africa + Europe + Americas), excluding historical scripts (and sign-writing). The only missing region is East Asia, aka CJK.

It has plenty of room for expansion, as of now it encompasses 11706 codepoints and 34256 glyphs.

otfinfo -u GoNotoContemporary.ttf | wc -l
11706
otfinfo -g GoNotoContemporary.ttf | wc -l
34256

So there is space for at least (65K - 34K) ~ 30K glyphs before we max out the 65535 glyph limit.

We also generate GoNotoCJKCore.otf which has about 10K code points and 20K glyphs, so it should all nicely fit-in the same font.

However, the idea fails because cmap table format 4 hits the 65535 limit.

otf2ttf GoNotoCJKCore2005.otf
pyftmerge --verbose --drop-tables+=vmtx,vhea GoNotoContemporary.ttf GoNotoCJKCore2005.ttf
# ... 
File "/home/ubuntu/projects/go-noto-universal/venv_fonty/lib/python3.8/site-packages/fontTools/ttLib/tables/_c_m_a_p.py", line 172, in compile
    chunk = table.compile(ttFont)
  File "/home/ubuntu/projects/go-noto-universal/venv_fonty/lib/python3.8/site-packages/fontTools/ttLib/tables/_c_m_a_p.py", line 904, in compile
    header = struct.pack(cmap_format_4_format, self.format, length, self.language,
struct.error: 'H' format requires 0 <= number <= 65535

The actual length is about 66600, so just a little over 65K. The aim of this issue/ticket is to figure out a way to overcome the cmap limit.

What is strange is that the original, non-subsetted CJK font itself has cmap length about 40K but the subsetted CJK has 51K cmap length!

A brute-force way I found is to use --no-layout-closure while subsetting, but it also removes locl feature, so JP or KR cannot use a CN font.

Fonts with lookups that use mark classes or mark sets are not merged correctly. If, say, a lookup in a source font uses mark set 0, the corresponding lookup in the merged font will also use mark set 0, even though the merged font’s mark set 0 might come from a different source font.

For example, here is <U+11C72, U+11C92, U+11C93> in Go Noto East Asia: And here it is in Noto Sans Marchen:

• Remove duplicated NotoSans-Regular which was mistakenly included twice. This frees up about 3300 glyphs
• Add more CJK-related blocks: CJK Symbols and Punctuation, Bopomofo, Bopomofo Extended, Halfwidth & Fullwidth Forms, CJK Strokes, CJK compatibility, CJK compatibilty forms, Enclosed CJK letters and months, Enclosed ideographic supplement, Katakana phonetic extensions
• Remove layout features related to vertical writing (vert, vkrn, vrt2, vhal, vpal, etc.)
• Move Cypriot and Glagolitic to "Go Noto Ancient"

Fixes #3. It doesn’t make any difference for continuous integration, because that always starts from scratch, but this is necessary if you already have a virtual environment with an older fontTools.

Noto Serif Tibetan includes a lot of unnecessary glyphs for conjuncts. Filtering them out makes a subset that covers all Tibetan code points while still fitting within the merged fonts.

Instead of delivering all fonts from single repo 1, upstream Google has decided to create separate git repo for each font. A web frontend with new development builds is available 2 but it is not all fonts are there yet.

Hi, I think there is an error in line spacing in Go Noto Universal - it is unnaturally big. When I compare it to other fonts and even to NotoSansRegular.ttf (https://github.com/googlefonts/noto-fonts/tree/main/hinted/ttf/NotoSans/NotoSans-Regular.ttf) so the file that is taken to build latin fonts in go-noto-universal. In the picture attached I show the comparison of Line Spacing in MS Word of NotoSansRegular and GoNotoCurrent.ttf: It is not only the case of MS Word, I checked that in Linux in other programs, there is also unnaturally big line spacing. It makes very uncomfortable to use this font and espacially in programs where I am not able to change it manually.

Thank you for providing this great library! I am currently trying to render text in various languages with the pygame library and it seems that when I am using GoNotoCurrent, I can render Japanese and Chinese glyphs just fine, but Korean glyphs are only rendered as empty boxes. When I am using GoNotoCJKCore, Korean is rendered properly as well, so I am wondering what the main difference between the two is. I can get around the issue by rendering my texts with the Pillow library and a libraqm layout engine which builds on harfbuzz, but this is horribly slow, so I'd prefer to keep using pygame and get it to work with GoNotoCurrent. Do you have an idea why rendering Korean might not work in my setup?

I used "GoNotoSouthEastAsia" with in Thai. That work perfectly but I can't find other weight like Thin, Semi Bold, Bold, ect. can you add other weight or how to compile it. that would be great.

thank you for build this project.