Also updated the script that is used to generate tests.With fonttools,
we now do instancing first and then subsetting.
With different order of subsetting and instancing operations on the same
VF file, fonttools seems to generate 2 different font files with different
glyph set.
1. do subsetting and then instancing: this seems result in a larger glyph
set in the font file. Lookups are collected from both retained features
and all possible alternate featurevariations, this leads to a larger
glyph set after glyph closurei. And instancer doesn't redo glyph
closure, it does lookups pruning only.
2. do instancing and then subsetting: lookups are collected from
features that are replaced already and possible alternate feature
variations
we should not cache visited langsys cause 2 different Record<Langsys>
could have different Tag while pointing to the same Langsys, a langsys
is redundant in Record<Langsys> A does not mean it's redundant in Record
B. Same thing for visited_script.
Also adding the number of features in the LangSys's feature list to the
visited langsys count so it's more accurate.
Plus some improvement in langsys compare()
cur_intersected_glyphs gets modified during recursion leading to incorrect filtering of sub tables in some cases. So don't use cur_intersected_glyphs. Instead just add an additional entry onto the parent_active_glyphs () stack.
Additionaly expands NotoNastaliqUrdu tests to include coverage of the issue from #3397.
- When pos_glyphs is empty, use current full glyphs set as input for
subsequent recursive closure process
- Also increase max_lookup_visit_count to 35000 cause a real font file hit
previous limit 20000 and some lookups are dropped unexpectedly
Though the spec said FeatureRecords are sorted alphabetically by feature
tag, there're font files with unsorted FeatureList. And harfbuzz is not
able to subset these files correctly because we use binary search in
finding featureRecords when collecting lookups. Also
find_duplicate_features needs to be updated to handle this.
If the post subset cmap12 table is equivalent to another cmap subtable don't include the 12 table in the final subset. Matches change https://github.com/fonttools/fonttools/pull/2146 from fontTools.
Composite glyph collection was happening along side colrv0 glyph collection which meant it was possible to miss grabbing the component glyphs for a glyph added by colrv0.
- subset class def 1 against the coverage table.
- Don't re-use class 0 in class def 2.
- Ignore class 0 glyphs for the purposes of determing format 1 vs format 2 encoding for ClassDef.
Add an additional test case which demonstrates these issues.
Qunxin Liu
Garret Rieger
Behdad Esfahbod